migrate ui

packages/stream_chat/lib/src/api/channel.dart

@@ -912,7 +912,10 @@ class Channel {
 
   void _initState(ChannelState channelState) {
     state = ChannelClientState(this, channelState);
-    client.state.channels[cid!] = this;
+
+    if (cid != null) {
+      client.state.channels[cid!] = this;
+    }
     if (!_initializedCompleter.isCompleted) {
       _initializedCompleter.complete(true);
     }

packages/stream_chat/lib/src/client.dart

@@ -798,11 +798,13 @@ class StreamChatClient {
     for (final channelState in channelStates) {
       final channel = channels[channelState.channel!.cid];
       if (channel != null) {
-        channel.state!.updateChannelState(channelState);
+        channel.state?.updateChannelState(channelState);
         newChannels.add(channel);
       } else {
         final newChannel = Channel.fromState(this, channelState);
-        channels[newChannel.cid!] = newChannel;
+        if (newChannel.cid != null) {
+          channels[newChannel.cid!] = newChannel;
+        }
         newChannels.add(newChannel);
       }
     }
@@ -1513,7 +1515,7 @@ class ClientState {
   /// The current list of channels in memory
   Map<String, Channel> get channels => _channelsController.value!;
 
-  set channels(Map<String, Channel>? v) {
+  set channels(Map<String, Channel> v) {
     if (v != null) _channelsController.add(v);
   }
 

packages/stream_chat/lib/src/models/attachment.dart

@@ -33,7 +33,7 @@ class Attachment extends Equatable {
     this.authorIcon,
     this.assetUrl,
     List<Action>? actions,
-    this.extraData,
+    this.extraData = const {},
     this.file,
     UploadState? uploadState,
   })  : id = id ?? const Uuid().v4(),
@@ -110,8 +110,11 @@ class Attachment extends Equatable {
   late final UploadState uploadState;
 
   /// Map of custom channel extraData
-  @JsonKey(includeIfNull: false)
+  @JsonKey(
-  final Map<String, Object>? extraData;
+    includeIfNull: false,
+    defaultValue: {},
+  )
+  final Map<String, Object> extraData;
 
   /// The attachment ID.
   ///

packages/stream_chat/lib/src/models/attachment.g.dart

@@ -31,8 +31,9 @@ Attachment _$AttachmentFromJson(Map<String, dynamic> json) {
             .toList() ??
         [],
     extraData: (json['extra_data'] as Map<String, dynamic>?)?.map(
-      (k, e) => MapEntry(k, e as Object),
+          (k, e) => MapEntry(k, e as Object),
-    ),
+        ) ??
+        {},
     file: json['file'] == null
         ? null
         : AttachmentFile.fromJson(json['file'] as Map<String, dynamic>),
@@ -71,7 +72,7 @@ Map<String, dynamic> _$AttachmentToJson(Attachment instance) {
   val['actions'] = instance.actions.map((e) => e.toJson()).toList();
   writeNotNull('file', instance.file?.toJson());
   val['upload_state'] = instance.uploadState.toJson();
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   val['id'] = instance.id;
   return val;
 }

packages/stream_chat/lib/src/models/attachment_file.dart

@@ -59,10 +59,10 @@ String? _toString(Uint8List? bytes) {
 class AttachmentFile {
   /// Creates a new [AttachmentFile] instance.
   const AttachmentFile({
+    required this.size,
     this.path,
     this.name,
     this.bytes,
-    this.size,
   }) : assert(
           path != null || bytes != null,
           'Either path or bytes should be != null',

packages/stream_chat/lib/src/models/channel_model.dart

@@ -21,7 +21,7 @@ class ChannelModel {
     DateTime? updatedAt,
     this.deletedAt,
     this.memberCount = 0,
-    this.extraData,
+    this.extraData = const {},
     this.team,
   })  : assert(
           (cid != null && cid.contains(':')) || (id != null && type != null),
@@ -83,8 +83,11 @@ class ChannelModel {
   final int memberCount;
 
   /// Map of custom channel extraData
-  @JsonKey(includeIfNull: false)
+  @JsonKey(
-  final Map<String, Object>? extraData;
+    includeIfNull: false,
+    defaultValue: {},
+  )
+  final Map<String, Object> extraData;
 
   /// The team the channel belongs to
   @JsonKey(includeIfNull: false, toJson: Serialization.readOnly)
@@ -108,9 +111,8 @@ class ChannelModel {
   ];
 
   /// Shortcut for channel name
-  String get name => extraData?.containsKey('name') == true
+  String get name =>
-      ? extraData!['name'] as String
+      extraData.containsKey('name') ? extraData['name'] as String : cid;
-      : cid;
 
   /// Serialize to json
   Map<String, dynamic> toJson() => Serialization.moveFromExtraDataToRoot(

packages/stream_chat/lib/src/models/channel_model.g.dart

@@ -32,8 +32,9 @@ ChannelModel _$ChannelModelFromJson(Map<String, dynamic> json) {
         : DateTime.parse(json['deleted_at'] as String),
     memberCount: json['member_count'] as int? ?? 0,
     extraData: (json['extra_data'] as Map<String, dynamic>?)?.map(
-      (k, e) => MapEntry(k, e as Object),
+          (k, e) => MapEntry(k, e as Object),
-    ),
+        ) ??
+        {},
     team: json['team'] as String?,
   );
 }
@@ -59,7 +60,7 @@ Map<String, dynamic> _$ChannelModelToJson(ChannelModel instance) {
   writeNotNull('updated_at', readonly(instance.updatedAt));
   writeNotNull('deleted_at', readonly(instance.deletedAt));
   writeNotNull('member_count', readonly(instance.memberCount));
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   writeNotNull('team', readonly(instance.team));
   return val;
 }

packages/stream_chat/lib/src/models/event.dart

@@ -193,7 +193,7 @@ class EventChannel extends ChannelModel {
           updatedAt: updatedAt,
           deletedAt: deletedAt,
           memberCount: memberCount,
-          extraData: extraData,
+          extraData: extraData ?? {},
         );
 
   /// Create a new instance from a json

packages/stream_chat/lib/src/models/event.g.dart

@@ -90,8 +90,9 @@ EventChannel _$EventChannelFromJson(Map<String, dynamic> json) {
         : DateTime.parse(json['deleted_at'] as String),
     memberCount: json['member_count'] as int? ?? 0,
     extraData: (json['extra_data'] as Map<String, dynamic>?)?.map(
-      (k, e) => MapEntry(k, e as Object),
+          (k, e) => MapEntry(k, e as Object),
-    ),
+        ) ??
+        {},
   );
 }
 
@@ -116,7 +117,7 @@ Map<String, dynamic> _$EventChannelToJson(EventChannel instance) {
   writeNotNull('updated_at', readonly(instance.updatedAt));
   writeNotNull('deleted_at', readonly(instance.deletedAt));
   writeNotNull('member_count', readonly(instance.memberCount));
-  writeNotNull('extra_data', instance.extraData);
+  val['extra_data'] = instance.extraData;
   val['members'] = instance.members?.map((e) => e.toJson()).toList();
   return val;
 }

packages/stream_chat_flutter/lib/src/attachment/attachment_title.dart

@@ -6,12 +6,12 @@ import '../utils.dart';
 
 class AttachmentTitle extends StatelessWidget {
   const AttachmentTitle({
-    Key key,
+    Key? key,
-    @required this.attachment,
+    required this.attachment,
-    @required this.messageTheme,
+    required this.messageTheme,
   }) : super(key: key);
 
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
   final Attachment attachment;
 
   @override
@@ -19,7 +19,7 @@ class AttachmentTitle extends StatelessWidget {
     return GestureDetector(
       onTap: () {
         if (attachment.titleLink != null) {
-          launchURL(context, attachment.titleLink);
+          launchURL(context, attachment.titleLink!);
         }
       },
       child: Padding(
@@ -28,17 +28,18 @@ class AttachmentTitle extends StatelessWidget {
           mainAxisSize: MainAxisSize.min,
           crossAxisAlignment: CrossAxisAlignment.stretch,
           children: <Widget>[
-            Text(
+            if (attachment.title != null)
-              attachment.title,
+              Text(
-              overflow: TextOverflow.ellipsis,
+                attachment.title!,
-              style: messageTheme.messageText.copyWith(
+                overflow: TextOverflow.ellipsis,
-                color: StreamChatTheme.of(context).colorTheme.accentBlue,
+                style: messageTheme?.messageText?.copyWith(
-                fontWeight: FontWeight.bold,
+                  color: StreamChatTheme.of(context).colorTheme.accentBlue,
+                  fontWeight: FontWeight.bold,
+                ),
               ),
-            ),
             if (attachment.titleLink != null || attachment.ogScrapeUrl != null)
               Text(
-                Uri.parse(attachment.titleLink ?? attachment.ogScrapeUrl)
+                Uri.parse(attachment.titleLink ?? attachment.ogScrapeUrl!)
                     .authority
                     .split('.')
                     .reversed
@@ -46,7 +47,7 @@ class AttachmentTitle extends StatelessWidget {
                     .toList()
                     .reversed
                     .join('.'),
-                style: messageTheme.messageText,
+                style: messageTheme?.messageText,
               ),
           ],
         ),

packages/stream_chat_flutter/lib/src/attachment/attachment_upload_state_builder.dart

@@ -8,55 +8,52 @@ typedef FailedBuilder = Widget Function(BuildContext, String);
 class AttachmentUploadStateBuilder extends StatelessWidget {
   final Message message;
   final Attachment attachment;
-  final FailedBuilder failedBuilder;
+  final FailedBuilder? failedBuilder;
-  final WidgetBuilder successBuilder;
+  final WidgetBuilder? successBuilder;
-  final InProgressBuilder inProgressBuilder;
+  final InProgressBuilder? inProgressBuilder;
-  final WidgetBuilder preparingBuilder;
+  final WidgetBuilder? preparingBuilder;
 
   const AttachmentUploadStateBuilder({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.attachment,
+    required this.attachment,
     this.failedBuilder,
     this.successBuilder,
     this.inProgressBuilder,
     this.preparingBuilder,
-  })  : assert(message != null),
+  }) : super(key: key);
-        assert(attachment != null),
-        super(key: key);
 
   @override
   Widget build(BuildContext context) {
-    if (message.status == null || message.status == MessageSendingStatus.sent) {
+    if (message.status == MessageSendingStatus.sent) {
       return Offstage();
     }
 
     final messageId = message.id;
     final attachmentId = attachment.id;
 
-    var inProgress = inProgressBuilder;
+    final inProgress = inProgressBuilder ??
-    inProgress ??= (context, int sent, int total) {
+        (context, int sent, int total) {
-      return _InProgressState(
+          return _InProgressState(
-        sent: sent,
+            sent: sent,
-        total: total,
+            total: total,
-        attachmentId: attachmentId,
+            attachmentId: attachmentId,
-      );
+          );
-    };
+        };
 
-    var failed = failedBuilder;
+    final failed = failedBuilder ??
-    failed ??= (context, error) {
+        (context, error) {
-      return _FailedState(
+          return _FailedState(
-        error: error,
+            error: error,
-        messageId: messageId,
+            messageId: messageId,
-        attachmentId: attachmentId,
+            attachmentId: attachmentId,
-      );
+          );
-    };
+        };
 
-    var success = successBuilder;
+    final success = successBuilder ?? (context) => _SuccessState();
-    success ??= (context) => _SuccessState();
 
-    var preparing = preparingBuilder;
+    final preparing = preparingBuilder ??
-    preparing ??= (context) => _PreparingState(attachmentId: attachmentId);
+        (context) => _PreparingState(attachmentId: attachmentId);
 
     return attachment.uploadState.when(
       preparing: () => preparing(context),
@@ -68,13 +65,13 @@ class AttachmentUploadStateBuilder extends StatelessWidget {
 }
 
 class _IconButton extends StatelessWidget {
-  final Widget icon;
+  final Widget? icon;
   final double iconSize;
-  final VoidCallback onPressed;
+  final VoidCallback? onPressed;
-  final Color fillColor;
+  final Color? fillColor;
 
   const _IconButton({
-    Key key,
+    Key? key,
     this.icon,
     this.iconSize = 24.0,
     this.onPressed,
@@ -95,7 +92,9 @@ class _IconButton extends StatelessWidget {
         onPressed: onPressed,
         fillColor:
             fillColor ?? StreamChatTheme.of(context).colorTheme.overlayDark,
-        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
+        shape: RoundedRectangleBorder(
+          borderRadius: BorderRadius.circular(16),
+        ),
         child: icon,
       ),
     );
@@ -106,8 +105,8 @@ class _PreparingState extends StatelessWidget {
   final String attachmentId;
 
   const _PreparingState({
-    Key key,
+    Key? key,
-    @required this.attachmentId,
+    required this.attachmentId,
   }) : super(key: key);
 
   @override
@@ -144,10 +143,10 @@ class _InProgressState extends StatelessWidget {
   final String attachmentId;
 
   const _InProgressState({
-    Key key,
+    Key? key,
-    @required this.sent,
+    required this.sent,
-    @required this.total,
+    required this.total,
-    @required this.attachmentId,
+    required this.attachmentId,
   }) : super(key: key);
 
   @override
@@ -179,15 +178,15 @@ class _InProgressState extends StatelessWidget {
 }
 
 class _FailedState extends StatelessWidget {
-  final String error;
+  final String? error;
   final String messageId;
   final String attachmentId;
 
   const _FailedState({
-    Key key,
+    Key? key,
     this.error,
-    @required this.messageId,
+    required this.messageId,
-    @required this.attachmentId,
+    required this.attachmentId,
   }) : super(key: key);
 
   @override
@@ -203,7 +202,7 @@ class _FailedState extends StatelessWidget {
             color: theme.colorTheme.white,
           ),
           onPressed: () {
-            return channel.retryAttachmentUpload(messageId, attachmentId);
+            channel.retryAttachmentUpload(messageId, attachmentId);
           },
         ),
         Center(
@@ -213,7 +212,10 @@ class _FailedState extends StatelessWidget {
               color: theme.colorTheme.overlayDark.withOpacity(0.6),
             ),
             child: Padding(
-              padding: const EdgeInsets.symmetric(vertical: 6, horizontal: 12),
+              padding: const EdgeInsets.symmetric(
+                vertical: 6,
+                horizontal: 12,
+              ),
               child: Text(
                 'UPLOAD ERROR',
                 style: theme.textTheme.footnote.copyWith(

packages/stream_chat_flutter/lib/src/attachment/attachment_widget.dart

@@ -13,15 +13,9 @@ extension AttachmentSourceX on AttachmentSource {
   /// Its prototype depends on the AttachmentSource defined.
   // ignore: missing_return
   T when<T>({
-    @required T Function() local,
+    required T Function() local,
-    @required T Function() network,
+    required T Function() network,
   }) {
-    assert(() {
-      if (local == null || network == null) {
-        throw 'check for all possible cases';
-      }
-      return true;
-    }());
     switch (this) {
       case AttachmentSource.local:
         return local();
@@ -32,30 +26,32 @@ extension AttachmentSourceX on AttachmentSource {
 }
 
 abstract class AttachmentWidget extends StatelessWidget {
-  final Size size;
+  final Size? size;
+  final AttachmentSource? _source;
   final Message message;
   final Attachment attachment;
-  final AttachmentSource _source;
 
-  AttachmentSource get source => _source ?? attachment.file != null
+  AttachmentSource get source =>
-      ? AttachmentSource.local
+      _source ??
-      : AttachmentSource.network;
+      (attachment.file != null
+          ? AttachmentSource.local
+          : AttachmentSource.network);
 
   const AttachmentWidget({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.attachment,
+    required this.attachment,
     this.size,
-    AttachmentSource source,
+    AttachmentSource? source,
   })  : _source = source,
         super(key: key);
 }
 
 class AttachmentError extends StatelessWidget {
-  final Size size;
+  final Size? size;
 
   const AttachmentError({
-    Key key,
+    Key? key,
     this.size,
   }) : super(key: key);
 

packages/stream_chat_flutter/lib/src/attachment/file_attachment.dart

@@ -11,19 +11,24 @@ import '../upload_progress_indicator.dart';
 import 'attachment_widget.dart';
 
 class FileAttachment extends AttachmentWidget {
-  final Widget title;
+  final Widget? title;
-  final Widget trailing;
+  final Widget? trailing;
-  final VoidCallback onAttachmentTap;
+  final VoidCallback? onAttachmentTap;
 
   const FileAttachment({
-    Key key,
+    Key? key,
-    @required Message message,
+    required Message message,
-    @required Attachment attachment,
+    required Attachment attachment,
-    Size size,
+    Size? size,
     this.title,
     this.trailing,
     this.onAttachmentTap,
-  }) : super(key: key, message: message, attachment: attachment, size: size);
+  }) : super(
+          key: key,
+          message: message,
+          attachment: attachment,
+          size: size,
+        );
 
   bool get isVideoAttachment => attachment.title?.mimeType?.type == 'video';
 
@@ -31,6 +36,7 @@ class FileAttachment extends AttachmentWidget {
 
   @override
   Widget build(BuildContext context) {
+    final colorTheme = StreamChatTheme.of(context).colorTheme;
     return Material(
       child: GestureDetector(
         onTap: onAttachmentTap,
@@ -38,10 +44,10 @@ class FileAttachment extends AttachmentWidget {
           width: size?.width ?? 100,
           height: 56.0,
           decoration: BoxDecoration(
-            color: StreamChatTheme.of(context).colorTheme.white,
+            color: colorTheme.white,
             borderRadius: BorderRadius.circular(12),
             border: Border.all(
-              color: StreamChatTheme.of(context).colorTheme.greyWhisper,
+              color: colorTheme.greyWhisper,
             ),
           ),
           child: Row(
@@ -60,7 +66,7 @@ class FileAttachment extends AttachmentWidget {
                   crossAxisAlignment: CrossAxisAlignment.start,
                   children: [
                     Text(
-                      attachment?.title ?? 'File',
+                      attachment.title ?? 'File',
                       style: StreamChatTheme.of(context).textTheme.bodyBold,
                       maxLines: 1,
                       overflow: TextOverflow.ellipsis,
@@ -93,34 +99,51 @@ class FileAttachment extends AttachmentWidget {
         type: MaterialType.transparency,
         shape: _getDefaultShape(context),
         child: source.when(
-          local: () => Image.memory(
+          local: () {
-            attachment.file.bytes,
+            if (attachment.file?.bytes == null) {
-            fit: BoxFit.cover,
+              return getFileTypeImage(attachment.extraData['other'] as String?);
-            errorBuilder: (_, obj, trace) {
+            }
-              return getFileTypeImage(attachment.extraData['other']);
+            return Image.memory(
-            },
+              attachment.file!.bytes!,
-          ),
+              fit: BoxFit.cover,
-          network: () => CachedNetworkImage(
+              errorBuilder: (_, obj, trace) {
-            imageUrl: attachment.imageUrl ??
+                return getFileTypeImage(
-                attachment.assetUrl ??
+                    attachment.extraData['other'] as String?);
-                attachment.thumbUrl,
+              },
-            fit: BoxFit.cover,
+            );
-            errorWidget: (_, obj, trace) {
+          },
-              return getFileTypeImage(attachment.extraData['other']);
+          network: () {
-            },
+            if ((attachment.imageUrl ??
-            placeholder: (_, __) {
+                    attachment.assetUrl ??
-              return Shimmer.fromColors(
+                    attachment.thumbUrl) ==
-                baseColor: StreamChatTheme.of(context).colorTheme.greyGainsboro,
+                null) {
-                highlightColor:
+              return getFileTypeImage(attachment.extraData['other'] as String?);
-                    StreamChatTheme.of(context).colorTheme.whiteSmoke,
+            }
-                child: Image.asset(
+            return CachedNetworkImage(
+              imageUrl: attachment.imageUrl ??
+                  attachment.assetUrl ??
+                  attachment.thumbUrl!,
+              fit: BoxFit.cover,
+              errorWidget: (_, obj, trace) {
+                return getFileTypeImage(
+                    attachment.extraData['other'] as String?);
+              },
+              placeholder: (_, __) {
+                final image = Image.asset(
                   'images/placeholder.png',
                   fit: BoxFit.cover,
                   package: 'stream_chat_flutter',
-                ),
+                );
-              );
+
-            },
+                final colorTheme = StreamChatTheme.of(context).colorTheme;
-          ),
+                return Shimmer.fromColors(
+                  baseColor: colorTheme.greyGainsboro,
+                  highlightColor: colorTheme.whiteSmoke,
+                  child: image,
+                );
+              },
+            );
+          },
         ),
       );
     }
@@ -132,7 +155,7 @@ class FileAttachment extends AttachmentWidget {
         shape: _getDefaultShape(context),
         child: source.when(
           local: () => VideoThumbnailImage(
-            video: attachment.file.path,
+            video: attachment.file?.path,
             placeholderBuilder: (_) {
               return Center(
                 child: Container(
@@ -158,14 +181,14 @@ class FileAttachment extends AttachmentWidget {
         ),
       );
     }
-    return getFileTypeImage(attachment.extraData['mime_type']);
+    return getFileTypeImage(attachment.extraData['mime_type'] as String?);
   }
 
   Widget _buildButton({
-    Widget icon,
+    Widget? icon,
     double iconSize = 24.0,
-    VoidCallback onPressed,
+    VoidCallback? onPressed,
-    Color fillColor,
+    Color? fillColor,
   }) {
     return Container(
       height: iconSize,
@@ -189,7 +212,7 @@ class FileAttachment extends AttachmentWidget {
     final channel = StreamChannel.of(context).channel;
     final attachmentId = attachment.id;
     var trailingWidget = trailing;
-    trailingWidget ??= attachment.uploadState?.when(
+    trailingWidget ??= attachment.uploadState.when(
           preparing: () => Padding(
             padding: const EdgeInsets.all(8.0),
             child: _buildButton(
@@ -220,7 +243,7 @@ class FileAttachment extends AttachmentWidget {
               icon: StreamSvgIcon.retry(color: theme.colorTheme.white),
               fillColor: theme.colorTheme.overlayDark,
               onPressed: () => channel.retryAttachmentUpload(
-                message?.id,
+                message.id,
                 attachmentId,
               ),
             ),
@@ -236,9 +259,7 @@ class FileAttachment extends AttachmentWidget {
           },
         );
 
-    if (message != null &&
+    if (message.status == MessageSendingStatus.sent) {
-        (message.status == null ||
-            message.status == MessageSendingStatus.sent)) {
       trailingWidget = IconButton(
         icon: StreamSvgIcon.cloudDownload(color: theme.colorTheme.black),
         padding: const EdgeInsets.all(8),
@@ -262,11 +283,8 @@ class FileAttachment extends AttachmentWidget {
     final textStyle = theme.textTheme.footnote.copyWith(
       color: theme.colorTheme.grey,
     );
-    return attachment.uploadState?.when(
+    return attachment.uploadState.when(
           preparing: () {
-            if (message == null) {
-              return Text('${fileSize(size, 2)}', style: textStyle);
-            }
             return UploadProgressIndicator(
               uploaded: 0,
               total: double.maxFinite.toInt(),

packages/stream_chat_flutter/lib/src/attachment/giphy_attachment.dart

@@ -9,17 +9,15 @@ import '../stream_svg_icon.dart';
 import 'attachment_widget.dart';
 
 class GiphyAttachment extends AttachmentWidget {
-  final MessageTheme messageTheme;
+  final ShowMessageCallback? onShowMessage;
-  final ShowMessageCallback onShowMessage;
+  final ValueChanged<ReturnActionType>? onReturnAction;
-  final ValueChanged<ReturnActionType> onReturnAction;
+  final VoidCallback? onAttachmentTap;
-  final VoidCallback onAttachmentTap;
 
   const GiphyAttachment({
-    Key key,
+    Key? key,
-    @required Message message,
+    required Message message,
-    @required Attachment attachment,
+    required Attachment attachment,
-    Size size,
+    Size? size,
-    this.messageTheme,
     this.onShowMessage,
     this.onReturnAction,
     this.onAttachmentTap,
@@ -29,10 +27,10 @@ class GiphyAttachment extends AttachmentWidget {
   Widget build(BuildContext context) {
     final imageUrl =
         attachment.thumbUrl ?? attachment.imageUrl ?? attachment.assetUrl;
-    if (imageUrl == null && source == AttachmentSource.network) {
+    if (imageUrl == null) {
       return AttachmentError();
     }
-    if (attachment.actions != null) {
+    if (attachment.actions.isNotEmpty) {
       return _buildSendingAttachment(context, imageUrl);
     }
     return _buildSentAttachment(context, imageUrl);
@@ -73,7 +71,7 @@ class GiphyAttachment extends AttachmentWidget {
                     if (attachment.title != null)
                       Flexible(
                         child: Text(
-                          attachment.title,
+                          attachment.title!,
                           style: TextStyle(
                             color: StreamChatTheme.of(context)
                                 .colorTheme
@@ -199,10 +197,11 @@ class GiphyAttachment extends AttachmentWidget {
                         child: Text(
                           'Send',
                           style: TextStyle(
-                              color: StreamChatTheme.of(context)
+                            color: StreamChatTheme.of(context)
-                                  .colorTheme
+                                .colorTheme
-                                  .accentBlue,
+                                .accentBlue,
-                              fontWeight: FontWeight.bold),
+                            fontWeight: FontWeight.bold,
+                          ),
                         ),
                       ),
                     ),
@@ -259,8 +258,7 @@ class GiphyAttachment extends AttachmentWidget {
             channel: channel,
             child: FullScreenMedia(
               mediaAttachments: [attachment],
-              userName: message.user.name,
+              userName: message.user?.name,
-              sentAt: message.createdAt,
               message: message,
               onShowMessage: onShowMessage,
             ),
@@ -268,7 +266,7 @@ class GiphyAttachment extends AttachmentWidget {
         },
       ),
     );
-    if (res != null) onReturnAction(res);
+    if (res != null) onReturnAction?.call(res);
   }
 
   Widget _buildSentAttachment(BuildContext context, String imageUrl) {
@@ -282,14 +280,13 @@ class GiphyAttachment extends AttachmentWidget {
               channel: channel,
               child: FullScreenMedia(
                 mediaAttachments: [attachment],
-                userName: message.user.name,
+                userName: message.user?.name,
-                sentAt: message.createdAt,
                 message: message,
                 onShowMessage: onShowMessage,
               ),
             );
           }));
-          if (res != null) onReturnAction(res);
+          if (res != null) onReturnAction!(res);
         },
         child: Stack(
           children: [
@@ -297,16 +294,17 @@ class GiphyAttachment extends AttachmentWidget {
               height: size?.height,
               width: size?.width,
               placeholder: (_, __) {
+                final image = Image.asset(
+                  'images/placeholder.png',
+                  fit: BoxFit.cover,
+                  package: 'stream_chat_flutter',
+                );
+
+                final colorTheme = StreamChatTheme.of(context).colorTheme;
                 return Shimmer.fromColors(
-                  baseColor:
+                  baseColor: colorTheme.greyGainsboro,
-                      StreamChatTheme.of(context).colorTheme.greyGainsboro,
+                  highlightColor: colorTheme.whiteSmoke,
-                  highlightColor:
+                  child: image,
-                      StreamChatTheme.of(context).colorTheme.whiteSmoke,
-                  child: Image.asset(
-                    'images/placeholder.png',
-                    fit: BoxFit.cover,
-                    package: 'stream_chat_flutter',
-                  ),
                 );
               },
               imageUrl: imageUrl,

packages/stream_chat_flutter/lib/src/attachment/image_attachment.dart

@@ -10,35 +10,40 @@ import 'attachment_title.dart';
 import 'attachment_widget.dart';
 
 class ImageAttachment extends AttachmentWidget {
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
   final bool showTitle;
-  final ShowMessageCallback onShowMessage;
+  final ShowMessageCallback? onShowMessage;
-  final ValueChanged<ReturnActionType> onReturnAction;
+  final ValueChanged<ReturnActionType>? onReturnAction;
-  final VoidCallback onAttachmentTap;
+  final VoidCallback? onAttachmentTap;
 
   const ImageAttachment({
-    Key key,
+    Key? key,
-    @required Message message,
+    required Message message,
-    @required Attachment attachment,
+    required Attachment attachment,
-    Size size,
+    Size? size,
     this.messageTheme,
     this.showTitle = false,
     this.onShowMessage,
     this.onReturnAction,
     this.onAttachmentTap,
-  }) : super(key: key, message: message, attachment: attachment, size: size);
+  }) : super(
+          key: key,
+          message: message,
+          attachment: attachment,
+          size: size,
+        );
 
   @override
   Widget build(BuildContext context) {
     return source.when(
       local: () {
-        if (attachment.localUri == null) {
+        if (attachment.localUri == null || attachment.file?.bytes == null) {
           return AttachmentError(size: size);
         }
         return _buildImageAttachment(
           context,
           Image.memory(
-            attachment.file.bytes,
+            attachment.file!.bytes!,
             height: size?.height,
             width: size?.width,
             fit: BoxFit.cover,
@@ -85,15 +90,16 @@ class ImageAttachment extends AttachmentWidget {
             height: size?.height,
             width: size?.width,
             placeholder: (_, __) {
+              final image = Image.asset(
+                'images/placeholder.png',
+                fit: BoxFit.cover,
+                package: 'stream_chat_flutter',
+              );
+              final colorTheme = StreamChatTheme.of(context).colorTheme;
               return Shimmer.fromColors(
-                baseColor: StreamChatTheme.of(context).colorTheme.greyGainsboro,
+                baseColor: colorTheme.greyGainsboro,
-                highlightColor:
+                highlightColor: colorTheme.whiteSmoke,
-                    StreamChatTheme.of(context).colorTheme.whiteSmoke,
+                child: image,
-                child: Image.asset(
-                  'images/placeholder.png',
-                  fit: BoxFit.cover,
-                  package: 'stream_chat_flutter',
-                ),
               );
             },
             imageUrl: imageUrl,
@@ -109,7 +115,7 @@ class ImageAttachment extends AttachmentWidget {
 
   Widget _buildImageAttachment(BuildContext context, Widget imageWidget) {
     return ConstrainedBox(
-      constraints: BoxConstraints.loose(size),
+      constraints: BoxConstraints.loose(size!),
       child: Column(
         children: <Widget>[
           Expanded(
@@ -127,8 +133,7 @@ class ImageAttachment extends AttachmentWidget {
                                 channel: channel,
                                 child: FullScreenMedia(
                                   mediaAttachments: [attachment],
-                                  userName: message.user.name,
+                                  userName: message.user?.name,
-                                  sentAt: message.createdAt,
                                   message: message,
                                   onShowMessage: onShowMessage,
                                 ),
@@ -136,7 +141,7 @@ class ImageAttachment extends AttachmentWidget {
                             },
                           ),
                         );
-                        if (result != null) onReturnAction(result);
+                        if (result != null) onReturnAction?.call(result);
                       },
                   child: imageWidget,
                 ),
@@ -152,7 +157,7 @@ class ImageAttachment extends AttachmentWidget {
           ),
           if (showTitle && attachment.title != null)
             Material(
-              color: messageTheme.messageBackgroundColor,
+              color: messageTheme?.messageBackgroundColor,
               child: AttachmentTitle(
                 messageTheme: messageTheme,
                 attachment: attachment,

packages/stream_chat_flutter/lib/src/attachment/video_attachment.dart

@@ -8,21 +8,26 @@ import 'attachment_upload_state_builder.dart';
 import 'attachment_widget.dart';
 
 class VideoAttachment extends AttachmentWidget {
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
-  final ShowMessageCallback onShowMessage;
+  final ShowMessageCallback? onShowMessage;
-  final ValueChanged<ReturnActionType> onReturnAction;
+  final ValueChanged<ReturnActionType>? onReturnAction;
-  final VoidCallback onAttachmentTap;
+  final VoidCallback? onAttachmentTap;
 
   const VideoAttachment({
-    Key key,
+    Key? key,
-    @required Message message,
+    required Message message,
-    @required Attachment attachment,
+    required Attachment attachment,
-    Size size,
+    Size? size,
     this.messageTheme,
     this.onShowMessage,
     this.onReturnAction,
     this.onAttachmentTap,
-  }) : super(key: key, message: message, attachment: attachment, size: size);
+  }) : super(
+          key: key,
+          message: message,
+          attachment: attachment,
+          size: size,
+        );
 
   @override
   Widget build(BuildContext context) {
@@ -34,7 +39,7 @@ class VideoAttachment extends AttachmentWidget {
         return _buildVideoAttachment(
           context,
           VideoThumbnailImage(
-            video: attachment.file.path,
+            video: attachment.file?.path,
             height: size?.height,
             width: size?.width,
             fit: BoxFit.cover,
@@ -62,7 +67,7 @@ class VideoAttachment extends AttachmentWidget {
 
   Widget _buildVideoAttachment(BuildContext context, Widget videoWidget) {
     return ConstrainedBox(
-      constraints: BoxConstraints.loose(size),
+      constraints: BoxConstraints.loose(size ?? Size.infinite),
       child: Column(
         children: <Widget>[
           Expanded(
@@ -77,15 +82,14 @@ class VideoAttachment extends AttachmentWidget {
                           channel: channel,
                           child: FullScreenMedia(
                             mediaAttachments: [attachment],
-                            userName: message.user.name,
+                            userName: message.user?.name,
-                            sentAt: message.createdAt,
                             message: message,
                             onShowMessage: onShowMessage,
                           ),
                         ),
                       ),
                     );
-                    if (res != null) onReturnAction(res);
+                    if (res != null) onReturnAction?.call(res);
                   },
               child: Stack(
                 children: [
@@ -112,7 +116,7 @@ class VideoAttachment extends AttachmentWidget {
           ),
           if (attachment.title != null)
             Material(
-              color: messageTheme.messageBackgroundColor,
+              color: messageTheme?.messageBackgroundColor,
               child: AttachmentTitle(
                 messageTheme: messageTheme,
                 attachment: attachment,

packages/stream_chat_flutter/lib/src/attachment_actions_modal.dart

@@ -12,7 +12,7 @@ import 'extension.dart';
 /// Callback to download an attachment asset
 typedef AttachmentDownloader = Future<String> Function(
   Attachment attachment, {
-  ProgressCallback progressCallback,
+  ProgressCallback? progressCallback,
 });
 
 /// Widget that shows the options in the gallery view
@@ -21,25 +21,25 @@ class AttachmentActionsModal extends StatelessWidget {
   final Message message;
 
   /// Current page index
-  final currentIndex;
+  final int currentIndex;
 
   /// Callback to show the message
-  final VoidCallback onShowMessage;
+  final VoidCallback? onShowMessage;
 
   /// Callback to download images
-  final AttachmentDownloader imageDownloader;
+  final AttachmentDownloader? imageDownloader;
 
   /// Callback to provide download files
-  final AttachmentDownloader fileDownloader;
+  final AttachmentDownloader? fileDownloader;
 
   /// Returns a new [AttachmentActionsModal]
   const AttachmentActionsModal({
-    @required this.currentIndex,
+    required this.currentIndex,
-    this.message,
+    required this.message,
     this.onShowMessage,
     this.imageDownloader,
     this.fileDownloader,
-  }) : assert(currentIndex != null, 'currentIndex cannot be null');
+  });
 
   @override
   Widget build(BuildContext context) {
@@ -99,11 +99,16 @@ class AttachmentActionsModal extends StatelessWidget {
                     () {
                       final attachment = message.attachments[currentIndex];
                       final isImage = attachment.type == 'image';
-                      final saveFile = fileDownloader ?? _downloadAttachment;
+                      final Future<String?> Function(Attachment,
-                      final saveImage = imageDownloader ?? _downloadAttachment;
+                              {void Function(int, int) progressCallback})
+                          saveFile = fileDownloader ?? _downloadAttachment;
+                      final Future<String?> Function(Attachment,
+                              {void Function(int, int) progressCallback})
+                          saveImage = imageDownloader ?? _downloadAttachment;
                       final downloader = isImage ? saveImage : saveFile;
 
-                      final progressNotifier = ValueNotifier<_DownloadProgress>(
+                      final progressNotifier =
+                          ValueNotifier<_DownloadProgress?>(
                         _DownloadProgress.initial(),
                       );
 
@@ -134,7 +139,7 @@ class AttachmentActionsModal extends StatelessWidget {
                       );
                     },
                   ),
-                  if (StreamChat.of(context).user.id == message.user.id)
+                  if (StreamChat.of(context).user?.id == message.user?.id)
                     _buildButton(
                       context,
                       'Delete',
@@ -164,8 +169,10 @@ class AttachmentActionsModal extends StatelessWidget {
                       color: theme.colorTheme.accentRed,
                     ),
                 ]
-                    .map<Widget>((e) =>
+                    .map<Widget>((e) => Align(
-                        Align(alignment: Alignment.centerRight, child: e))
+                          alignment: Alignment.centerRight,
+                          child: e,
+                        ))
                     .insertBetween(
                       Container(
                         height: 1,
@@ -184,9 +191,9 @@ class AttachmentActionsModal extends StatelessWidget {
     context,
     String title,
     StreamSvgIcon icon,
-    VoidCallback onTap, {
+    VoidCallback? onTap, {
-    Color color,
+    Color? color,
-    Key key,
+    Key? key,
   }) {
     return Material(
       key: key,
@@ -215,16 +222,16 @@ class AttachmentActionsModal extends StatelessWidget {
 
   Widget _buildDownloadProgressDialog(
     BuildContext context,
-    ValueNotifier<_DownloadProgress> progressNotifier,
+    ValueNotifier<_DownloadProgress?> progressNotifier,
   ) {
     final theme = StreamChatTheme.of(context);
     return WillPopScope(
       onWillPop: () => Future.value(false),
       child: ValueListenableBuilder(
         valueListenable: progressNotifier,
-        builder: (_, _DownloadProgress progress, __) {
+        builder: (_, _DownloadProgress? progress, __) {
           // Pop the dialog in case the progress is null or it's completed.
-          if (progress == null || progress?.toProgressIndicatorValue == 1.0) {
+          if (progress == null || progress.toProgressIndicatorValue == 1.0) {
             Future.delayed(
               const Duration(milliseconds: 500),
               Navigator.of(context).maybePop,
@@ -291,23 +298,23 @@ class AttachmentActionsModal extends StatelessWidget {
     );
   }
 
-  Future<String> _downloadAttachment(
+  Future<String?> _downloadAttachment(
     Attachment attachment, {
-    ProgressCallback progressCallback,
+    ProgressCallback? progressCallback,
   }) async {
-    String filePath;
+    String? filePath;
     final appDocDir = await getTemporaryDirectory();
     await Dio().download(
-      attachment.assetUrl ?? attachment.imageUrl ?? attachment.thumbUrl,
+      attachment.assetUrl ?? attachment.imageUrl ?? attachment.thumbUrl!,
       (Headers responseHeaders) {
-        final contentType = responseHeaders[Headers.contentTypeHeader];
+        final contentType = responseHeaders[Headers.contentTypeHeader]!;
-        final mimeType = contentType.first?.split('/')?.last;
+        final mimeType = contentType.first.split('/').last;
         filePath ??= '${appDocDir.path}/${attachment.id}.$mimeType';
         return filePath;
       },
       onReceiveProgress: progressCallback,
     );
-    final result = await ImageGallerySaver.saveFile(filePath);
+    final result = await ImageGallerySaver.saveFile(filePath!);
     return (result as Map)['filePath'];
   }
 }

packages/stream_chat_flutter/lib/src/back_button.dart

@@ -6,17 +6,17 @@ import '../stream_chat_flutter.dart';
 
 class StreamBackButton extends StatelessWidget {
   const StreamBackButton({
-    Key key,
+    Key? key,
     this.onPressed,
     this.showUnreads = false,
     this.cid,
   }) : super(key: key);
 
-  final VoidCallback onPressed;
+  final VoidCallback? onPressed;
   final bool showUnreads;
 
   /// Channel cid used to retrieve unread count
-  final String cid;
+  final String? cid;
 
   @override
   Widget build(BuildContext context) {
@@ -34,7 +34,7 @@ class StreamBackButton extends StatelessWidget {
           hoverElevation: 0,
           onPressed: () {
             if (onPressed != null) {
-              onPressed();
+              onPressed!();
             } else {
               Navigator.maybePop(context);
             }

packages/stream_chat_flutter/lib/src/channel_bottom_sheet.dart

@@ -5,7 +5,7 @@ import 'channel_info.dart';
 import 'option_list_tile.dart';
 
 class ChannelBottomSheet extends StatefulWidget {
-  final VoidCallback onViewInfoTap;
+  final VoidCallback? onViewInfoTap;
 
   ChannelBottomSheet({this.onViewInfoTap});
 
@@ -18,13 +18,13 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
 
   @override
   Widget build(BuildContext context) {
-    var channel = StreamChannel.of(context).channel;
+    final channel = StreamChannel.of(context).channel;
 
-    var members = channel.state.members;
+    final members = channel.state?.members ?? [];
 
-    var userAsMember =
+    final userAsMember = members
-        members.firstWhere((e) => e.user.id == StreamChat.of(context).user.id);
+        .firstWhere((e) => e.user?.id == StreamChat.of(context).user?.id);
-    var isOwner = userAsMember.role == 'owner';
+    final isOwner = userAsMember.role == 'owner';
 
     return Material(
       color: StreamChatTheme.of(context).colorTheme.white,
@@ -73,8 +73,8 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
                       UserAvatar(
                         user: members
                             .firstWhere(
-                                (e) => e.user.id != userAsMember.user.id)
+                                (e) => e.user?.id != userAsMember.user?.id)
-                            .user,
+                            .user!,
                         constraints: BoxConstraints(
                           maxHeight: 64.0,
                           maxWidth: 64.0,
@@ -88,10 +88,11 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
                       ),
                       Text(
                         members
-                            .firstWhere(
+                                .firstWhere(
-                                (e) => e.user.id != userAsMember.user.id)
+                                    (e) => e.user?.id != userAsMember.user?.id)
-                            .user
+                                .user
-                            .name,
+                                ?.name ??
+                            '',
                         style:
                             StreamChatTheme.of(context).textTheme.footnoteBold,
                         maxLines: 1,
@@ -113,7 +114,7 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
                           child: Column(
                             children: [
                               UserAvatar(
-                                user: members[index].user,
+                                user: members[index].user!,
                                 constraints: BoxConstraints.tightFor(
                                   height: 64.0,
                                   width: 64.0,
@@ -126,7 +127,7 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
                                 height: 6.0,
                               ),
                               Text(
-                                members[index].user.name,
+                                members[index].user?.name ?? '',
                                 style: StreamChatTheme.of(context)
                                     .textTheme
                                     .footnoteBold,
@@ -220,7 +221,7 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
         color: StreamChatTheme.of(context).colorTheme.accentRed,
       ),
     );
-    var channel = StreamChannel.of(context).channel;
+    final channel = StreamChannel.of(context).channel;
     if (res == true) {
       await channel.delete();
       Navigator.pop(context);
@@ -240,7 +241,10 @@ class _ChannelBottomSheetState extends State<ChannelBottomSheet> {
     );
     if (res == true) {
       final channel = StreamChannel.of(context).channel;
-      await channel.removeMembers([StreamChat.of(context).user.id]);
+      final user = StreamChat.of(context).user;
+      if (user != null) {
+        await channel.removeMembers([user.id]);
+      }
       Navigator.pop(context);
     }
   }

packages/stream_chat_flutter/lib/src/channel_header.dart

@@ -58,13 +58,13 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
 
   /// Callback to call when pressing the back button.
   /// By default it calls [Navigator.pop]
-  final VoidCallback onBackPressed;
+  final VoidCallback? onBackPressed;
 
   /// Callback to call when the header is tapped.
-  final VoidCallback onTitleTap;
+  final VoidCallback? onTitleTap;
 
   /// Callback to call when the image is tapped.
-  final VoidCallback onImageTap;
+  final VoidCallback? onImageTap;
 
   /// If true the typing indicator will be rendered if a user is typing
   final bool showTypingIndicator;
@@ -72,21 +72,21 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
   final bool showConnectionStateTile;
 
   /// Title widget
-  final Widget title;
+  final Widget? title;
 
   /// Subtitle widget
-  final Widget subtitle;
+  final Widget? subtitle;
 
   /// Leading widget
-  final Widget leading;
+  final Widget? leading;
 
   /// AppBar actions
   /// By default it shows the [ChannelImage]
-  final List<Widget> actions;
+  final List<Widget>? actions;
 
   /// Creates a channel header
   ChannelHeader({
-    Key key,
+    Key? key,
     this.showBackButton = true,
     this.onBackPressed,
     this.onTitleTap,
@@ -151,12 +151,12 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
                             .channelTheme
                             .channelHeaderTheme
                             .avatarTheme
-                            .borderRadius,
+                            ?.borderRadius,
                         constraints: StreamChatTheme.of(context)
                             .channelTheme
                             .channelHeaderTheme
                             .avatarTheme
-                            .constraints,
+                            ?.constraints,
                         onTap: onImageTap,
                       ),
                     ),

packages/stream_chat_flutter/lib/src/channel_image.dart

@@ -46,7 +46,7 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 class ChannelImage extends StatelessWidget {
   /// Instantiate a new ChannelImage
   const ChannelImage({
-    Key key,
+    Key? key,
     this.channel,
     this.constraints,
     this.onTap,
@@ -56,20 +56,20 @@ class ChannelImage extends StatelessWidget {
     this.selectionThickness = 4,
   }) : super(key: key);
 
-  final BorderRadius borderRadius;
+  final BorderRadius? borderRadius;
 
   /// The channel to show the image of
-  final Channel channel;
+  final Channel? channel;
 
   /// The diameter of the image
-  final BoxConstraints constraints;
+  final BoxConstraints? constraints;
 
   /// The function called when the image is tapped
-  final VoidCallback onTap;
+  final VoidCallback? onTap;
 
   final bool selected;
 
-  final Color selectionColor;
+  final Color? selectionColor;
 
   final double selectionThickness;
 
@@ -81,30 +81,30 @@ class ChannelImage extends StatelessWidget {
       stream: channel.extraDataStream,
       initialData: channel.extraData,
       builder: (context, snapshot) {
-        String image;
+        String? image;
-        if (snapshot.data?.containsKey('image') == true) {
+        if (snapshot.data!.containsKey('image') == true) {
-          image = snapshot.data['image'];
+          image = snapshot.data!['image'];
-        } else if (channel.state.members?.length == 2) {
+        } else if (channel.state?.members.length == 2) {
-          final otherMember = channel.state.members
+          final otherMember = channel.state?.members
-              .firstWhere((member) => member.user.id != streamChat.user.id);
+              .firstWhere((member) => member.user?.id != streamChat.user?.id);
           return StreamBuilder<User>(
-              stream: streamChat.client.state.usersStream
+              stream: streamChat.client.state.usersStream.map(
-                  .map((users) => users[otherMember.userId]),
+                  (users) => users[otherMember?.userId] ?? otherMember!.user!),
-              initialData: otherMember.user,
+              initialData: otherMember!.user,
               builder: (context, snapshot) {
                 return UserAvatar(
                   borderRadius: borderRadius ??
                       StreamChatTheme.of(context)
                           .channelPreviewTheme
                           .avatarTheme
-                          .borderRadius,
+                          ?.borderRadius,
-                  user: snapshot.data ?? otherMember.user,
+                  user: snapshot.data ?? otherMember.user!,
                   constraints: constraints ??
                       StreamChatTheme.of(context)
                           .channelPreviewTheme
                           .avatarTheme
-                          .constraints,
+                          ?.constraints,
-                  onTap: onTap != null ? (_) => onTap() : null,
+                  onTap: onTap != null ? (_) => onTap!() : null,
                   selected: selected,
                   selectionColor: selectionColor ??
                       StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -112,25 +112,25 @@ class ChannelImage extends StatelessWidget {
                 );
               });
         } else {
-          final images = channel.state.members
+          final images = channel.state?.members
               .where((member) =>
-                  member.user.id != streamChat.user.id &&
+                  member.user?.id != streamChat.user?.id &&
-                  member.user.extraData['image'] != null)
+                  member.user?.extraData['image'] != null)
               .take(4)
-              .map((e) => e.user.extraData['image'] as String)
+              .map((e) => e.user?.extraData['image'] as String?)
               .toList();
           return GroupImage(
-            images: images,
+            images: images ?? [],
             borderRadius: borderRadius ??
                 StreamChatTheme.of(context)
                     .channelPreviewTheme
                     .avatarTheme
-                    .borderRadius,
+                    ?.borderRadius,
             constraints: constraints ??
                 StreamChatTheme.of(context)
                     .channelPreviewTheme
                     .avatarTheme
-                    .constraints,
+                    ?.constraints,
             onTap: onTap,
             selected: selected,
             selectionColor: selectionColor ??
@@ -144,13 +144,13 @@ class ChannelImage extends StatelessWidget {
               StreamChatTheme.of(context)
                   .channelPreviewTheme
                   .avatarTheme
-                  .borderRadius,
+                  ?.borderRadius,
           child: Container(
             constraints: constraints ??
                 StreamChatTheme.of(context)
                     .channelPreviewTheme
                     .avatarTheme
-                    .constraints,
+                    ?.constraints,
             decoration: BoxDecoration(
               color: StreamChatTheme.of(context).colorTheme.accentBlue,
             ),
@@ -165,7 +165,7 @@ class ChannelImage extends StatelessWidget {
                           return Center(
                             child: Text(
                               snapshot.data?.containsKey('name') ?? false
-                                  ? snapshot.data['name'][0]
+                                  ? snapshot.data!['name'][0]
                                   : '',
                               style: TextStyle(
                                 color: StreamChatTheme.of(context)
@@ -178,8 +178,10 @@ class ChannelImage extends StatelessWidget {
                         },
                         fit: BoxFit.cover,
                       )
-                    : StreamChatTheme.of(context)
+                    : StreamChatTheme.of(context).defaultChannelImage(
-                        .defaultChannelImage(context, channel),
+                        context,
+                        channel,
+                      ),
                 Material(
                   color: Colors.transparent,
                   child: InkWell(
@@ -197,14 +199,15 @@ class ChannelImage extends StatelessWidget {
                     StreamChatTheme.of(context)
                         .ownMessageTheme
                         .avatarTheme
-                        .borderRadius) +
+                        ?.borderRadius ??
+                    BorderRadius.zero) +
                 BorderRadius.circular(selectionThickness),
             child: Container(
               constraints: constraints ??
                   StreamChatTheme.of(context)
                       .ownMessageTheme
                       .avatarTheme
-                      .constraints,
+                      ?.constraints,
               color: selectionColor ??
                   StreamChatTheme.of(context).colorTheme.accentBlue,
               child: Padding(

packages/stream_chat_flutter/lib/src/channel_info.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:flutter/material.dart';
 import 'package:jiffy/jiffy.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
@@ -8,14 +9,14 @@ class ChannelInfo extends StatelessWidget {
   final Channel channel;
 
   /// The style of the text displayed
-  final TextStyle textStyle;
+  final TextStyle? textStyle;
 
   /// If true the typing indicator will be rendered if a user is typing
   final bool showTypingIndicator;
 
   const ChannelInfo({
-    Key key,
+    Key? key,
-    @required this.channel,
+    required this.channel,
     this.textStyle,
     this.showTypingIndicator = true,
   }) : super(key: key);
@@ -24,8 +25,8 @@ class ChannelInfo extends StatelessWidget {
   Widget build(BuildContext context) {
     final client = StreamChat.of(context).client;
     return StreamBuilder<List<Member>>(
-      stream: channel.state.membersStream,
+      stream: channel.state?.membersStream,
-      initialData: channel.state.members,
+      initialData: channel.state?.members,
       builder: (context, snapshot) {
         return ConnectionStatusBuilder(
           statusBuilder: (context, status) {
@@ -45,12 +46,13 @@ class ChannelInfo extends StatelessWidget {
     );
   }
 
-  Widget _buildConnectedTitleState(BuildContext context, List<Member> members) {
+  Widget _buildConnectedTitleState(
+      BuildContext context, List<Member>? members) {
     var alternativeWidget;
 
-    if (channel.memberCount != null && channel.memberCount > 2) {
+    if (channel.memberCount != null && channel.memberCount! > 2) {
       var text = '${channel.memberCount} Members';
-      final watcherCount = channel.state.watcherCount ?? 0;
+      final watcherCount = channel.state?.watcherCount ?? 0;
       if (watcherCount > 0) text += ' $watcherCount Online';
       alternativeWidget = Text(
         text,
@@ -60,20 +62,19 @@ class ChannelInfo extends StatelessWidget {
             .subtitle,
       );
     } else {
-      final otherMember = members.firstWhere(
+      final otherMember = members?.firstWhereOrNull(
-        (element) => element.userId != StreamChat.of(context).user.id,
+        (element) => element.userId != StreamChat.of(context).user?.id,
-        orElse: () => null,
       );
 
       if (otherMember != null) {
-        if (otherMember.user.online) {
+        if (otherMember.user?.online == true) {
           alternativeWidget = Text(
             'Online',
             style: textStyle,
           );
         } else {
           alternativeWidget = Text(
-            'Last seen ${Jiffy(otherMember.user.lastActive).fromNow()}',
+            'Last seen ${Jiffy(otherMember.user?.lastActive).fromNow()}',
             style: textStyle,
           );
         }
@@ -112,7 +113,9 @@ class ChannelInfo extends StatelessWidget {
   }
 
   Widget _buildDisconnectedTitleState(
-      BuildContext context, StreamChatClient client) {
+    BuildContext context,
+    StreamChatClient client,
+  ) {
     return Row(
       mainAxisAlignment: MainAxisAlignment.center,
       children: [
@@ -131,11 +134,11 @@ class ChannelInfo extends StatelessWidget {
           ),
           onPressed: () async {
             await client.disconnect();
-            return client.connect();
+            await client.connect();
           },
           child: Text(
             'Try Again',
-            style: textStyle.copyWith(
+            style: textStyle?.copyWith(
               color: StreamChatTheme.of(context).colorTheme.accentBlue,
             ),
           ),

packages/stream_chat_flutter/lib/src/channel_list_header.dart

@@ -10,7 +10,7 @@ import 'connection_status_builder.dart';
 import 'info_tile.dart';
 import 'stream_chat.dart';
 
-typedef _TitleBuilder = Widget Function(
+typedef TitleBuilder = Widget Function(
   BuildContext context,
   ConnectionStatus status,
   StreamChatClient client,
@@ -50,7 +50,7 @@ typedef _TitleBuilder = Widget Function(
 class ChannelListHeader extends StatelessWidget implements PreferredSizeWidget {
   /// Instantiates a ChannelListHeader
   const ChannelListHeader({
-    Key key,
+    Key? key,
     this.client,
     this.titleBuilder,
     this.onUserAvatarTap,
@@ -63,32 +63,32 @@ class ChannelListHeader extends StatelessWidget implements PreferredSizeWidget {
   }) : super(key: key);
 
   /// Pass this if you don't have a [StreamChatClient] in your widget tree.
-  final StreamChatClient client;
+  final StreamChatClient? client;
 
   /// Use this to build your own title as per different [ConnectionStatus]
-  final _TitleBuilder titleBuilder;
+  final TitleBuilder? titleBuilder;
 
   /// Callback to call when pressing the user avatar button.
   /// By default it calls Scaffold.of(context).openDrawer()
-  final Function(User) onUserAvatarTap;
+  final Function(User)? onUserAvatarTap;
 
   /// Callback to call when pressing the new chat button.
-  final VoidCallback onNewChatButtonTap;
+  final VoidCallback? onNewChatButtonTap;
 
   final bool showConnectionStateTile;
 
-  final VoidCallback preNavigationCallback;
+  final VoidCallback? preNavigationCallback;
 
   /// Subtitle widget
-  final Widget subtitle;
+  final Widget? subtitle;
 
   /// Leading widget
   /// By default it shows the logged in user avatar
-  final Widget leading;
+  final Widget? leading;
 
   /// AppBar actions
   /// By default it shows the new chat button
-  final List<Widget> actions;
+  final List<Widget>? actions;
 
   @override
   Widget build(BuildContext context) {
@@ -123,25 +123,27 @@ class ChannelListHeader extends StatelessWidget implements PreferredSizeWidget {
             centerTitle: true,
             leading: leading ??
                 Center(
-                  child: UserAvatar(
+                  child: user != null
-                    user: user,
+                      ? UserAvatar(
-                    showOnlineStatus: false,
+                          user: user,
-                    onTap: onUserAvatarTap ??
+                          showOnlineStatus: false,
-                        (_) {
+                          onTap: onUserAvatarTap ??
-                          if (preNavigationCallback != null) {
+                              (_) {
-                            preNavigationCallback();
+                                if (preNavigationCallback != null) {
-                          }
+                                  preNavigationCallback!();
-                          Scaffold.of(context).openDrawer();
+                                }
-                        },
+                                Scaffold.of(context).openDrawer();
-                    borderRadius: StreamChatTheme.of(context)
+                              },
-                        .channelListHeaderTheme
+                          borderRadius: StreamChatTheme.of(context)
-                        .avatarTheme
+                              .channelListHeaderTheme
-                        .borderRadius,
+                              .avatarTheme
-                    constraints: StreamChatTheme.of(context)
+                              ?.borderRadius,
-                        .channelListHeaderTheme
+                          constraints: StreamChatTheme.of(context)
-                        .avatarTheme
+                              .channelListHeaderTheme
-                        .constraints,
+                              .avatarTheme
-                  ),
+                              ?.constraints,
+                        )
+                      : Offstage(),
                 ),
             actions: actions ??
                 [
@@ -181,7 +183,7 @@ class ChannelListHeader extends StatelessWidget implements PreferredSizeWidget {
                 Builder(
                   builder: (context) {
                     if (titleBuilder != null) {
-                      return titleBuilder(context, status, _client);
+                      return titleBuilder!(context, status, _client);
                     }
                     switch (status) {
                       case ConnectionStatus.connected:
@@ -225,40 +227,46 @@ class ChannelListHeader extends StatelessWidget implements PreferredSizeWidget {
         SizedBox(width: 10),
         Text(
           'Searching for Network',
-          style:
+          style: StreamChatTheme.of(context)
-              StreamChatTheme.of(context).channelListHeaderTheme.title.copyWith(
+              .channelListHeaderTheme
-                    fontSize: 16,
+              .title
-                    fontWeight: FontWeight.bold,
+              ?.copyWith(
-                  ),
+                fontSize: 16,
+                fontWeight: FontWeight.bold,
+              ),
         ),
       ],
     );
   }
 
   Widget _buildDisconnectedTitleState(
-      BuildContext context, StreamChatClient client) {
+    BuildContext context,
+    StreamChatClient client,
+  ) {
     return Row(
       mainAxisAlignment: MainAxisAlignment.center,
       children: [
         Text(
           'Offline...',
-          style:
+          style: StreamChatTheme.of(context)
-              StreamChatTheme.of(context).channelListHeaderTheme.title.copyWith(
+              .channelListHeaderTheme
-                    fontSize: 16,
+              .title
-                    fontWeight: FontWeight.bold,
+              ?.copyWith(
-                  ),
+                fontSize: 16,
+                fontWeight: FontWeight.bold,
+              ),
         ),
         TextButton(
           onPressed: () async {
             await client.disconnect();
-            return client.connect();
+            await client.connect();
           },
           child: Text(
             'Try Again',
             style: StreamChatTheme.of(context)
                 .channelListHeaderTheme
                 .title
-                .copyWith(
+                ?.copyWith(
                   fontSize: 16,
                   fontWeight: FontWeight.bold,
                   color: StreamChatTheme.of(context).colorTheme.accentBlue,

packages/stream_chat_flutter/lib/src/channel_list_view.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_slidable/flutter_slidable.dart';
@@ -11,7 +12,7 @@ import 'channel_bottom_sheet.dart';
 import 'channel_preview.dart';
 
 /// Callback called when tapping on a channel
-typedef ChannelTapCallback = void Function(Channel, Widget);
+typedef ChannelTapCallback = void Function(Channel, Widget?);
 
 /// Builder used to create a custom [ChannelPreview] from a [Channel]
 typedef ChannelPreviewBuilder = Widget Function(BuildContext, Channel);
@@ -54,7 +55,7 @@ typedef ViewInfoCallback = void Function(Channel);
 class ChannelListView extends StatefulWidget {
   /// Instantiate a new ChannelListView
   ChannelListView({
-    Key key,
+    Key? key,
     this.filter,
     this.options,
     this.sort,
@@ -90,67 +91,67 @@ class ChannelListView extends StatefulWidget {
   ///
   /// state: if true returns the Channel state
   /// watch: if true listen to changes to this Channel in real time.
-  final Map<String, dynamic> options;
+  final Map<String, dynamic>? options;
 
   /// The sorting used for the channels matching the filters.
   /// Sorting is based on field and direction, multiple sorting options can be provided.
   /// You can sort based on last_updated, last_message_at, updated_at, created_at or member_count.
   /// Direction can be ascending or descending.
-  final List<SortOption<ChannelModel>> sort;
+  final List<SortOption<ChannelModel>>? sort;
 
   /// Pagination parameters
   /// limit: the number of channels to return (max is 30)
   /// offset: the offset (max is 1000)
   /// message_limit: how many messages should be included to each channel
-  final PaginationParams pagination;
+  final PaginationParams? pagination;
 
   /// Function called when tapping on a channel
   /// By default it calls [Navigator.push] building a [MaterialPageRoute]
   /// with the widget [channelWidget] as child.
-  final ChannelTapCallback onChannelTap;
+  final ChannelTapCallback? onChannelTap;
 
   /// Function called when long pressing on a channel
-  final Function(Channel) onChannelLongPress;
+  final Function(Channel)? onChannelLongPress;
 
   /// Widget used when opening a channel
-  final Widget channelWidget;
+  final Widget? channelWidget;
 
   /// Builder used to create a custom channel preview
-  final ChannelPreviewBuilder channelPreviewBuilder;
+  final ChannelPreviewBuilder? channelPreviewBuilder;
 
   /// Builder used to create a custom item separator
-  final Function(BuildContext, int) separatorBuilder;
+  final Function(BuildContext, int)? separatorBuilder;
 
   /// The function called when the image is tapped
-  final Function(Channel) onImageTap;
+  final Function(Channel)? onImageTap;
 
   /// Set it to false to disable the pull-to-refresh widget
   final bool pullToRefresh;
 
   /// Callback used in the default empty list widget
-  final VoidCallback onStartChatPressed;
+  final VoidCallback? onStartChatPressed;
 
   /// The number of children in the cross axis.
   final int crossAxisCount;
 
   /// The amount of space by which to inset the children.
-  final EdgeInsetsGeometry padding;
+  final EdgeInsetsGeometry? padding;
 
   final List<Channel> selectedChannels;
 
-  final ViewInfoCallback onViewInfoTap;
+  final ViewInfoCallback? onViewInfoTap;
 
   /// The builder that will be used in case of error
-  final ErrorBuilder errorBuilder;
+  final ErrorBuilder? errorBuilder;
 
   /// The builder that will be used in case of loading
-  final WidgetBuilder loadingBuilder;
+  final WidgetBuilder? loadingBuilder;
 
   /// The builder which is used when list of channels loads
-  final Function(BuildContext, List<Channel>) listBuilder;
+  final Function(BuildContext, List<Channel>)? listBuilder;
 
   /// The builder used when the channel list is empty.
-  final WidgetBuilder emptyBuilder;
+  final WidgetBuilder? emptyBuilder;
 
   @override
   _ChannelListViewState createState() => _ChannelListViewState();
@@ -164,7 +165,10 @@ class _ChannelListViewState extends State<ChannelListView> {
   @override
   Widget build(BuildContext context) {
     Widget child = ChannelListCore(
-      pagination: widget.pagination,
+      pagination: widget.pagination ??
+          const PaginationParams(
+            limit: 25,
+          ),
       options: widget.options,
       sort: widget.sort,
       filter: widget.filter,
@@ -177,26 +181,27 @@ class _ChannelListViewState extends State<ChannelListView> {
 
     if (widget.pullToRefresh) {
       child = RefreshIndicator(
-        onRefresh: () => _channelListController.loadData(),
+        onRefresh: () => _channelListController.loadData!(),
         child: child,
       );
     }
 
     return LazyLoadScrollView(
-      onEndOfPage: () => _channelListController.paginateData(),
+      onEndOfPage: () => _channelListController.paginateData!(),
       child: child,
     );
   }
 
   Widget _buildListView(BuildContext context, List<Channel> channels) {
-    Widget child;
+    late Widget child;
 
     if (channels.isNotEmpty) {
       if (widget.crossAxisCount > 1) {
         child = GridView.builder(
           padding: widget.padding,
           gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
-              crossAxisCount: widget.crossAxisCount),
+            crossAxisCount: widget.crossAxisCount,
+          ),
           itemCount: channels.length,
           physics: AlwaysScrollableScrollPhysics(),
           itemBuilder: (context, index) {
@@ -211,7 +216,7 @@ class _ChannelListViewState extends State<ChannelListView> {
               channels.isNotEmpty ? channels.length + 1 : channels.length,
           separatorBuilder: (_, index) {
             if (widget.separatorBuilder != null) {
-              return widget.separatorBuilder(context, index);
+              return widget.separatorBuilder!(context, index);
             }
             return _separatorBuilder(context, index);
           },
@@ -317,7 +322,7 @@ class _ChannelListViewState extends State<ChannelListView> {
           if (widget.crossAxisCount == 1) {
             if (i % 2 != 0) {
               if (widget.separatorBuilder != null) {
-                return widget.separatorBuilder(context, i);
+                return widget.separatorBuilder!(context, i);
               }
               return _separatorBuilder(context, i);
             }
@@ -447,7 +452,7 @@ class _ChannelListViewState extends State<ChannelListView> {
             style: Theme.of(context).textTheme.headline6,
           ),
           TextButton(
-            onPressed: () => _channelListController.loadData(),
+            onPressed: () => _channelListController.loadData!(),
             child: Text('Retry'),
           ),
         ],
@@ -459,24 +464,7 @@ class _ChannelListViewState extends State<ChannelListView> {
     final channelsProvider = ChannelsBloc.of(context);
     if (i < channels.length) {
       final channel = channels[i];
-      ChannelTapCallback onTap;
+      final onTap = _getChannelTap(context);
-      if (widget.onChannelTap != null) {
-        onTap = widget.onChannelTap;
-      } else {
-        onTap = (client, _) {
-          Navigator.push(
-            context,
-            MaterialPageRoute(
-              builder: (context) {
-                return StreamChannel(
-                  channel: client,
-                  child: widget.channelWidget,
-                );
-              },
-            ),
-          );
-        };
-      }
 
       final backgroundColor = StreamChatTheme.of(context).colorTheme.whiteSmoke;
       return StreamChannel(
@@ -509,7 +497,7 @@ class _ChannelListViewState extends State<ChannelListView> {
                           channel: channel,
                           child: ChannelBottomSheet(
                             onViewInfoTap: () {
-                              widget.onViewInfoTap(channel);
+                              widget.onViewInfoTap?.call(channel);
                             },
                           ),
                         );
@@ -520,9 +508,9 @@ class _ChannelListViewState extends State<ChannelListView> {
                 if ([
                   'admin',
                   'owner',
-                ].contains(channel.state.members
+                ].contains(channel.state!.members
-                    .firstWhere((m) => m.userId == channel.client.state.user.id,
+                    .firstWhereOrNull(
-                        orElse: () => null)
+                        (m) => m.userId == channel.client.state.user?.id)
                     ?.role))
                   IconSlideAction(
                     color: backgroundColor,
@@ -567,10 +555,35 @@ class _ChannelListViewState extends State<ChannelListView> {
     }
   }
 
-  Widget _gridItemBuilder(BuildContext context, int i, List<Channel> channels) {
+  ChannelTapCallback _getChannelTap(BuildContext context) {
-    var channel = channels[i];
+    ChannelTapCallback onTap;
+    if (widget.onChannelTap != null) {
+      onTap = widget.onChannelTap!;
+    } else {
+      onTap = (client, _) {
+        if (widget.channelWidget == null) {
+          return;
+        }
+        Navigator.push(
+          context,
+          MaterialPageRoute(
+            builder: (context) {
+              return StreamChannel(
+                channel: client,
+                child: widget.channelWidget!,
+              );
+            },
+          ),
+        );
+      };
+    }
+    return onTap;
+  }
 
-    var selected = widget.selectedChannels.contains(channel);
+  Widget _gridItemBuilder(BuildContext context, int i, List<Channel> channels) {
+    final channel = channels[i];
+
+    final selected = widget.selectedChannels.contains(channel);
 
     return Container(
       key: ValueKey<String>('CHANNEL-${channel.id}'),
@@ -586,7 +599,7 @@ class _ChannelListViewState extends State<ChannelListView> {
               width: 64,
               height: 64,
             ),
-            onTap: () => widget.onChannelTap(channel, null),
+            onTap: () => _getChannelTap(context),
           ),
           SizedBox(height: 7),
           Padding(
@@ -628,7 +641,7 @@ class _ChannelListViewState extends State<ChannelListView> {
               ),
             );
           }
-          return snapshot.data
+          return snapshot.data!
               ? Center(
                   child: Padding(
                     padding: const EdgeInsets.all(16.0),
@@ -644,7 +657,7 @@ class _ChannelListViewState extends State<ChannelListView> {
 
     return Container(
       height: 1,
-      color: effect.color.withOpacity(effect.alpha ?? 1.0),
+      color: effect.color!.withOpacity(effect.alpha ?? 1.0),
     );
   }
 }

packages/stream_chat_flutter/lib/src/channel_name.dart

@@ -10,12 +10,12 @@ import '../stream_chat_flutter.dart';
 class ChannelName extends StatelessWidget {
   /// Instantiate a new ChannelName
   const ChannelName({
-    Key key,
+    Key? key,
     this.textStyle,
   }) : super(key: key);
 
   /// The style of the text displayed
-  final TextStyle textStyle;
+  final TextStyle? textStyle;
 
   @override
   Widget build(BuildContext context) {
@@ -26,31 +26,31 @@ class ChannelName extends StatelessWidget {
       stream: channel.extraDataStream,
       initialData: channel.extraData,
       builder: (context, snapshot) {
-        return _buildName(snapshot.data, channel.state.members, client);
+        return _buildName(snapshot.data!, channel.state?.members, client);
       },
     );
   }
 
   Widget _buildName(
     Map<String, dynamic> extraData,
-    List<Member> members,
+    List<Member>? members,
     StreamChatState client,
   ) {
     return LayoutBuilder(
       builder: (context, constraints) {
-        String title;
+        String? title;
         if (extraData['name'] == null) {
           final otherMembers =
-              members.where((member) => member.userId != client.user.id);
+              members?.where((member) => member.userId != client.user!.id);
-          if (otherMembers.length == 1) {
+          if (otherMembers?.length == 1) {
-            title = otherMembers.first.user.name;
+            title = otherMembers!.first.user?.name;
-          } else if (otherMembers.isNotEmpty) {
+          } else if (otherMembers?.isNotEmpty == true) {
             final maxWidth = constraints.maxWidth;
-            final maxChars = maxWidth / textStyle.fontSize;
+            final maxChars = maxWidth / (textStyle?.fontSize ?? 1);
             var currentChars = 0;
             final currentMembers = <Member>[];
-            otherMembers.forEach((element) {
+            otherMembers!.forEach((element) {
-              final newLength = currentChars + element.user.name.length;
+              final newLength = currentChars + (element.user?.name.length ?? 0);
               if (newLength < maxChars) {
                 currentChars = newLength;
                 currentMembers.add(element);
@@ -60,7 +60,7 @@ class ChannelName extends StatelessWidget {
             final exceedingMembers =
                 otherMembers.length - currentMembers.length;
             title =
-                '${currentMembers.map((e) => e.user.name).join(', ')} ${exceedingMembers > 0 ? '+ $exceedingMembers' : ''}';
+                '${currentMembers.map((e) => e.user?.name).join(', ')} ${exceedingMembers > 0 ? '+ $exceedingMembers' : ''}';
           } else {
             title = 'No title';
           }
@@ -69,7 +69,7 @@ class ChannelName extends StatelessWidget {
         }
 
         return Text(
-          title,
+          title!,
           style: textStyle,
           overflow: TextOverflow.ellipsis,
         );

packages/stream_chat_flutter/lib/src/channel_preview.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:jiffy/jiffy.dart';
@@ -20,35 +21,35 @@ import 'channel_name.dart';
 /// Modify it to change the widget appearance.
 class ChannelPreview extends StatelessWidget {
   /// Function called when tapping this widget
-  final void Function(Channel) onTap;
+  final void Function(Channel)? onTap;
 
   /// Function called when long pressing this widget
-  final void Function(Channel) onLongPress;
+  final void Function(Channel)? onLongPress;
 
   /// Channel displayed
   final Channel channel;
 
   /// The function called when the image is tapped
-  final VoidCallback onImageTap;
+  final VoidCallback? onImageTap;
 
   /// Widget rendering the title
-  final Widget title;
+  final Widget? title;
 
   /// Widget rendering the subtitle
-  final Widget subtitle;
+  final Widget? subtitle;
 
   /// Widget rendering the leading element, by default it shows the [ChannelImage]
-  final Widget leading;
+  final Widget? leading;
 
   /// Widget rendering the trailing element, by default it shows the last message date
-  final Widget trailing;
+  final Widget? trailing;
 
   /// Widget rendering the sending indicator, by default it uses the [SendingIndicator] widget
-  final Widget sendingIndicator;
+  final Widget? sendingIndicator;
 
   ChannelPreview({
-    @required this.channel,
+    required this.channel,
-    Key key,
+    Key? key,
     this.onTap,
     this.onLongPress,
     this.onImageTap,
@@ -67,7 +68,7 @@ class ChannelPreview extends StatelessWidget {
         initialData: channel.isMuted,
         builder: (context, snapshot) {
           return Opacity(
-            opacity: snapshot.data ? 0.5 : 1,
+            opacity: snapshot.data! ? 0.5 : 1,
             child: ListTile(
               visualDensity: VisualDensity.compact,
               contentPadding: const EdgeInsets.symmetric(
@@ -75,12 +76,12 @@ class ChannelPreview extends StatelessWidget {
               ),
               onTap: () {
                 if (onTap != null) {
-                  onTap(channel);
+                  onTap!(channel);
                 }
               },
               onLongPress: () {
                 if (onLongPress != null) {
-                  onLongPress(channel);
+                  onLongPress!(channel);
                 }
               },
               leading: leading ??
@@ -97,13 +98,13 @@ class ChannelPreview extends StatelessWidget {
                         ),
                   ),
                   StreamBuilder<List<Member>>(
-                    stream: channel.state.membersStream,
+                    stream: channel.state?.membersStream,
-                    initialData: channel.state.members,
+                    initialData: channel.state?.members,
                     builder: (context, snapshot) {
                       if (!snapshot.hasData ||
-                          snapshot.data.isEmpty ||
+                          snapshot.data!.isEmpty ||
-                          !snapshot.data.any((Member e) =>
+                          !snapshot.data!.any((Member e) =>
-                              e.user.id == channel.client.state.user.id)) {
+                              e.user!.id == channel.client.state.user?.id)) {
                         return SizedBox();
                       }
                       return UnreadIndicator(
@@ -120,24 +121,24 @@ class ChannelPreview extends StatelessWidget {
                   sendingIndicator ??
                       Builder(
                         builder: (context) {
-                          final lastMessage = channel.state.messages.lastWhere(
+                          final lastMessage =
+                              channel.state?.messages.lastWhereOrNull(
                             (m) => !m.isDeleted && m.shadowed != true,
-                            orElse: () => null,
                           );
                           if (lastMessage?.user?.id ==
-                              StreamChat.of(context).user.id) {
+                              StreamChat.of(context).user?.id) {
                             return Padding(
                               padding: const EdgeInsets.only(right: 4.0),
                               child: SendingIndicator(
-                                message: lastMessage,
+                                message: lastMessage!,
                                 size: channelPreviewTheme.indicatorIconSize,
-                                isMessageRead: channel.state.read
+                                isMessageRead: channel.state!.read
                                         ?.where((element) =>
                                             element.user.id !=
-                                            channel.client.state.user.id)
+                                            channel.client.state.user!.id)
-                                        ?.where((element) => element.lastRead
+                                        .where((element) => element.lastRead
                                             .isAfter(lastMessage.createdAt))
-                                        ?.isNotEmpty ==
+                                        .isNotEmpty ==
                                     true,
                               ),
                             );
@@ -154,14 +155,14 @@ class ChannelPreview extends StatelessWidget {
   }
 
   Widget _buildDate(BuildContext context) {
-    return StreamBuilder<DateTime>(
+    return StreamBuilder<DateTime?>(
       stream: channel.lastMessageAtStream,
       initialData: channel.lastMessageAt,
       builder: (context, snapshot) {
         if (!snapshot.hasData) {
           return SizedBox();
         }
-        final lastMessageAt = snapshot.data.toLocal();
+        final lastMessageAt = snapshot.data!.toLocal();
 
         String stringDate;
         final now = DateTime.now();
@@ -211,60 +212,58 @@ class ChannelPreview extends StatelessWidget {
   }
 
   Widget _buildLastMessage(BuildContext context) {
-    return StreamBuilder<List<Message>>(
+    return StreamBuilder<List<Message>?>(
-      stream: channel.state.messagesStream,
+      stream: channel.state!.messagesStream,
-      initialData: channel.state.messages,
+      initialData: channel.state!.messages,
       builder: (context, snapshot) {
-        final lastMessage = snapshot.data?.lastWhere(
+        final lastMessage = snapshot.data
-            (m) => m.shadowed != true && !m.isDeleted,
+            ?.lastWhereOrNull((m) => m.shadowed != true && !m.isDeleted);
-            orElse: () => null);
         if (lastMessage == null) {
           return SizedBox();
         }
 
         var text = lastMessage.text;
-        if (lastMessage.attachments != null) {
+        final parts = <String>[
-          final parts = <String>[
+          ...lastMessage.attachments.map((e) {
-            ...lastMessage.attachments.map((e) {
+            if (e.type == 'image') {
-              if (e.type == 'image') {
+              return '📷';
-                return '📷';
+            } else if (e.type == 'video') {
-              } else if (e.type == 'video') {
+              return '🎬';
-                return '🎬';
+            } else if (e.type == 'giphy') {
-              } else if (e.type == 'giphy') {
+              return '[GIF]';
-                return '[GIF]';
+            }
-              }
+            return e == lastMessage.attachments.last
-              return e == lastMessage.attachments.last
+                ? (e.title ?? 'File')
-                  ? (e.title ?? 'File')
+                : '${e.title ?? 'File'} , ';
-                  : '${e.title ?? 'File'} , ';
+          }),
-            }).where((e) => e != null),
+          lastMessage.text ?? '',
-            lastMessage.text ?? '',
+        ];
-          ];
 
-          text = parts.join(' ');
+        text = parts.join(' ');
-        }
 
         return Text.rich(
           _getDisplayText(
             text,
             lastMessage.mentionedUsers,
             lastMessage.attachments,
-            StreamChatTheme.of(context).channelPreviewTheme.subtitle.copyWith(
+            StreamChatTheme.of(context).channelPreviewTheme.subtitle?.copyWith(
                 color: StreamChatTheme.of(context)
                     .channelPreviewTheme
                     .subtitle
-                    .color,
+                    ?.color,
                 fontStyle: (lastMessage.isSystem || lastMessage.isDeleted)
                     ? FontStyle.italic
                     : FontStyle.normal),
-            StreamChatTheme.of(context).channelPreviewTheme.subtitle.copyWith(
+            StreamChatTheme.of(context).channelPreviewTheme.subtitle?.copyWith(
-                color: StreamChatTheme.of(context)
+                  color: StreamChatTheme.of(context)
-                    .channelPreviewTheme
+                      .channelPreviewTheme
-                    .subtitle
+                      .subtitle
-                    .color,
+                      ?.color,
-                fontStyle: (lastMessage.isSystem || lastMessage.isDeleted)
+                  fontStyle: (lastMessage.isSystem || lastMessage.isDeleted)
-                    ? FontStyle.italic
+                      ? FontStyle.italic
-                    : FontStyle.normal,
+                      : FontStyle.normal,
-                fontWeight: FontWeight.bold),
+                  fontWeight: FontWeight.bold,
+                ),
           ),
           maxLines: 1,
           overflow: TextOverflow.ellipsis,
@@ -274,29 +273,28 @@ class ChannelPreview extends StatelessWidget {
   }
 
   TextSpan _getDisplayText(
-      String text,
+    String text,
-      List<User> mentions,
+    List<User> mentions,
-      List<Attachment> attachments,
+    List<Attachment> attachments,
-      TextStyle normalTextStyle,
+    TextStyle? normalTextStyle,
-      TextStyle mentionsTextStyle) {
+    TextStyle? mentionsTextStyle,
-    var textList = text.split(' ');
+  ) {
-    var resList = <TextSpan>[];
+    final textList = text.split(' ');
-    for (var e in textList) {
+    final resList = <TextSpan>[];
-      if (mentions != null &&
+    for (final e in textList) {
-          mentions.isNotEmpty &&
+      if (mentions.isNotEmpty &&
           mentions.any((element) => '@${element.name}' == e)) {
         resList.add(TextSpan(
           text: '$e ',
           style: mentionsTextStyle,
         ));
-      } else if (attachments != null &&
+      } else if (attachments.isNotEmpty &&
-          attachments.isNotEmpty &&
           attachments
               .where((e) => e.title != null)
               .any((element) => element.title == e)) {
         resList.add(TextSpan(
           text: '$e ',
-          style: normalTextStyle.copyWith(fontStyle: FontStyle.italic),
+          style: normalTextStyle?.copyWith(fontStyle: FontStyle.italic),
         ));
       } else {
         resList.add(TextSpan(

packages/stream_chat_flutter/lib/src/connection_status_builder.dart

@@ -11,26 +11,25 @@ import 'stream_chat.dart';
 class ConnectionStatusBuilder extends StatelessWidget {
   /// Creates a new ConnectionStatusBuilder
   const ConnectionStatusBuilder({
-    Key key,
+    Key? key,
-    @required this.statusBuilder,
+    required this.statusBuilder,
     this.initialStatus = ConnectionStatus.disconnected,
     this.connectionStatusStream,
     this.errorBuilder,
     this.loadingBuilder,
-  })  : assert(statusBuilder != null),
+  }) : super(key: key);
-        super(key: key);
 
   /// The connection status that will be used to create the initial snapshot.
   final ConnectionStatus initialStatus;
 
   /// The asynchronous computation to which this builder is currently connected.
-  final Stream<ConnectionStatus> connectionStatusStream;
+  final Stream<ConnectionStatus>? connectionStatusStream;
 
   /// The builder that will be used in case of error
-  final Widget Function(BuildContext context, Object error) errorBuilder;
+  final Widget Function(BuildContext context, Object? error)? errorBuilder;
 
   /// The builder that will be used in case of loading
-  final WidgetBuilder loadingBuilder;
+  final WidgetBuilder? loadingBuilder;
 
   /// The builder that will be used in case of data
   final Widget Function(BuildContext context, ConnectionStatus status)
@@ -46,15 +45,15 @@ class ConnectionStatusBuilder extends StatelessWidget {
       builder: (context, snapshot) {
         if (snapshot.hasError) {
           if (errorBuilder != null) {
-            return errorBuilder(context, snapshot.error);
+            return errorBuilder!(context, snapshot.error);
           }
           return Offstage();
         }
         if (!snapshot.hasData) {
-          if (loadingBuilder != null) return loadingBuilder(context);
+          if (loadingBuilder != null) return loadingBuilder!(context);
           return Offstage();
         }
-        return statusBuilder(context, snapshot.data);
+        return statusBuilder(context, snapshot.data!);
       },
     );
   }

packages/stream_chat_flutter/lib/src/date_divider.dart

@@ -8,8 +8,8 @@ class DateDivider extends StatelessWidget {
   final bool uppercase;
 
   const DateDivider({
-    Key key,
+    Key? key,
-    @required this.dateTime,
+    required this.dateTime,
     this.uppercase = false,
   }) : super(key: key);
 

packages/stream_chat_flutter/lib/src/deleted_message.dart

@@ -5,8 +5,8 @@ import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 
 class DeletedMessage extends StatelessWidget {
   const DeletedMessage({
-    Key key,
+    Key? key,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.borderRadiusGeometry,
     this.shape,
     this.borderSide,
@@ -14,16 +14,16 @@ class DeletedMessage extends StatelessWidget {
   }) : super(key: key);
 
   /// The theme of the message
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
 
   /// The border radius of the message text
-  final BorderRadiusGeometry borderRadiusGeometry;
+  final BorderRadiusGeometry? borderRadiusGeometry;
 
   /// The shape of the message text
-  final ShapeBorder shape;
+  final ShapeBorder? shape;
 
   /// The borderside of the message text
-  final BorderSide borderSide;
+  final BorderSide? borderSide;
 
   /// If true the widget will be mirrored
   final bool reverse;
@@ -34,7 +34,7 @@ class DeletedMessage extends StatelessWidget {
       transform: Matrix4.rotationY(reverse ? pi : 0),
       alignment: Alignment.center,
       child: Material(
-        color: messageTheme.messageBackgroundColor,
+        color: messageTheme?.messageBackgroundColor,
         shape: shape ??
             RoundedRectangleBorder(
               borderRadius: borderRadiusGeometry ?? BorderRadius.zero,
@@ -61,9 +61,9 @@ class DeletedMessage extends StatelessWidget {
             alignment: Alignment.center,
             child: Text(
               'Message deleted',
-              style: messageTheme.messageText.copyWith(
+              style: messageTheme?.messageText?.copyWith(
                 fontStyle: FontStyle.italic,
-                color: messageTheme.createdAt.color,
+                color: messageTheme?.createdAt?.color,
               ),
             ),
           ),

packages/stream_chat_flutter/lib/src/extension.dart

@@ -47,53 +47,53 @@ extension PlatformFileX on PlatformFile {
 }
 
 extension InputDecorationX on InputDecoration {
-  InputDecoration merge(InputDecoration other) {
+  InputDecoration merge(InputDecoration? other) {
     if (other == null) return this;
     return copyWith(
-      icon: other?.icon,
+      icon: other.icon,
-      labelText: other?.labelText,
+      labelText: other.labelText,
       labelStyle: labelStyle?.merge(other.labelStyle) ?? other.labelStyle,
-      helperText: other?.helperText,
+      helperText: other.helperText,
       helperStyle: helperStyle?.merge(other.helperStyle) ?? other.helperStyle,
-      helperMaxLines: other?.helperMaxLines,
+      helperMaxLines: other.helperMaxLines,
-      hintText: other?.hintText,
+      hintText: other.hintText,
       hintStyle: hintStyle?.merge(other.hintStyle) ?? other.hintStyle,
-      hintTextDirection: other?.hintTextDirection,
+      hintTextDirection: other.hintTextDirection,
-      hintMaxLines: other?.hintMaxLines,
+      hintMaxLines: other.hintMaxLines,
-      errorText: other?.errorText,
+      errorText: other.errorText,
       errorStyle: errorStyle?.merge(other.errorStyle) ?? other.errorStyle,
-      errorMaxLines: other?.errorMaxLines,
+      errorMaxLines: other.errorMaxLines,
-      floatingLabelBehavior: other?.floatingLabelBehavior,
+      floatingLabelBehavior: other.floatingLabelBehavior,
-      isCollapsed: other?.isCollapsed,
+      isCollapsed: other.isCollapsed,
-      isDense: other?.isDense,
+      isDense: other.isDense,
-      contentPadding: other?.contentPadding,
+      contentPadding: other.contentPadding,
-      prefixIcon: other?.prefixIcon,
+      prefixIcon: other.prefixIcon,
-      prefix: other?.prefix,
+      prefix: other.prefix,
-      prefixText: other?.prefixText,
+      prefixText: other.prefixText,
-      prefixIconConstraints: other?.prefixIconConstraints,
+      prefixIconConstraints: other.prefixIconConstraints,
       prefixStyle: prefixStyle?.merge(other.prefixStyle) ?? other.prefixStyle,
-      suffixIcon: other?.suffixIcon,
+      suffixIcon: other.suffixIcon,
-      suffix: other?.suffix,
+      suffix: other.suffix,
-      suffixText: other?.suffixText,
+      suffixText: other.suffixText,
       suffixStyle: suffixStyle?.merge(other.suffixStyle) ?? other.suffixStyle,
-      suffixIconConstraints: other?.suffixIconConstraints,
+      suffixIconConstraints: other.suffixIconConstraints,
-      counter: other?.counter,
+      counter: other.counter,
-      counterText: other?.counterText,
+      counterText: other.counterText,
       counterStyle:
           counterStyle?.merge(other.counterStyle) ?? other.counterStyle,
-      filled: other?.filled,
+      filled: other.filled,
-      fillColor: other?.fillColor,
+      fillColor: other.fillColor,
-      focusColor: other?.focusColor,
+      focusColor: other.focusColor,
-      hoverColor: other?.hoverColor,
+      hoverColor: other.hoverColor,
-      errorBorder: other?.errorBorder,
+      errorBorder: other.errorBorder,
-      focusedBorder: other?.focusedBorder,
+      focusedBorder: other.focusedBorder,
-      focusedErrorBorder: other?.focusedErrorBorder,
+      focusedErrorBorder: other.focusedErrorBorder,
-      disabledBorder: other?.disabledBorder,
+      disabledBorder: other.disabledBorder,
-      enabledBorder: other?.enabledBorder,
+      enabledBorder: other.enabledBorder,
-      border: other?.border,
+      border: other.border,
-      enabled: other?.enabled,
+      enabled: other.enabled,
-      semanticCounterText: other?.semanticCounterText,
+      semanticCounterText: other.semanticCounterText,
-      alignLabelWithHint: other?.alignLabelWithHint,
+      alignLabelWithHint: other.alignLabelWithHint,
     );
   }
 }

packages/stream_chat_flutter/lib/src/full_screen_media.dart

@@ -24,19 +24,18 @@ class FullScreenMedia extends StatefulWidget {
 
   final int startIndex;
   final String userName;
-  final DateTime sentAt;
+  final ShowMessageCallback? onShowMessage;
-  final ShowMessageCallback onShowMessage;
 
   /// Instantiate a new FullScreenImage
   const FullScreenMedia({
-    Key key,
+    Key? key,
-    @required this.mediaAttachments,
+    required this.mediaAttachments,
-    this.message,
+    required this.message,
     this.startIndex = 0,
-    this.userName = '',
+    String? userName,
-    this.sentAt,
     this.onShowMessage,
-  }) : super(key: key);
+  })  : userName = userName ?? '',
+        super(key: key);
 
   @override
   _FullScreenMediaState createState() => _FullScreenMediaState();
@@ -46,10 +45,10 @@ class _FullScreenMediaState extends State<FullScreenMedia>
     with SingleTickerProviderStateMixin {
   bool _optionsShown = true;
 
-  AnimationController _controller;
+  late final AnimationController _controller;
-  PageController _pageController;
+  late final PageController _pageController;
 
-  int _currentPage;
+  late int _currentPage;
 
   final videoPackages = <String, VideoPackage>{};
 
@@ -101,10 +100,11 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                           attachment.assetUrl ??
                           attachment.thumbUrl;
                       return PhotoView(
-                        imageProvider:
+                        imageProvider: (imageUrl == null &&
-                            imageUrl == null && attachment.localUri != null
+                                attachment.localUri != null &&
-                                ? Image.memory(attachment.file.bytes).image
+                                attachment.file?.bytes != null)
-                                : CachedNetworkImageProvider(imageUrl),
+                            ? Image.memory(attachment.file!.bytes!).image
+                            : CachedNetworkImageProvider(imageUrl!),
                         maxScale: PhotoViewComputedScale.covered,
                         minScale: PhotoViewComputedScale.contained,
                         heroAttributes: PhotoViewHeroAttributes(
@@ -112,12 +112,12 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                         ),
                         backgroundDecoration: BoxDecoration(
                           color: ColorTween(
-                                  begin: StreamChatTheme.of(context)
+                            begin: StreamChatTheme.of(context)
-                                      .channelTheme
+                                .channelTheme
-                                      .channelHeaderTheme
+                                .channelHeaderTheme
-                                      .color,
+                                .color,
-                                  end: Colors.black)
+                            end: Colors.black,
-                              .lerp(_controller.value),
+                          ).lerp(_controller.value),
                         ),
                         onTapUp: (a, b, c) {
                           setState(() {
@@ -131,7 +131,7 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                         },
                       );
                     } else if (attachment.type == 'video') {
-                      final controller = videoPackages[attachment.id];
+                      final controller = videoPackages[attachment.id]!;
                       if (!controller.initialized) {
                         return Center(
                           child: CircularProgressIndicator(),
@@ -153,7 +153,7 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                             vertical: 50.0,
                           ),
                           child: Chewie(
-                            controller: controller.chewieController,
+                            controller: controller.chewieController!,
                           ),
                         ),
                       );
@@ -171,9 +171,8 @@ class _FullScreenMediaState extends State<FullScreenMedia>
               children: [
                 ImageHeader(
                   userName: widget.userName,
-                  sentAt: widget.message.createdAt == null
+                  sentAt:
-                      ? ''
+                      'Sent ${getDay(widget.message.createdAt.toLocal())} at ${Jiffy(widget.message.createdAt.toLocal()).format('HH:mm')}',
-                      : 'Sent ${getDay(widget.message.createdAt)} at ${Jiffy(widget.sentAt.toLocal()).format('HH:mm')}',
                   onBackPressed: () {
                     Navigator.of(context).pop();
                   },
@@ -181,8 +180,10 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                   urls: widget.mediaAttachments,
                   currentIndex: _currentPage,
                   onShowMessage: () {
-                    widget.onShowMessage(
+                    widget.onShowMessage?.call(
-                        widget.message, StreamChannel.of(context).channel);
+                      widget.message,
+                      StreamChannel.of(context).channel,
+                    );
                   },
                 ),
                 if (widget.message.type != 'ephemeral')
@@ -194,9 +195,11 @@ class _FullScreenMediaState extends State<FullScreenMedia>
                     mediaSelectedCallBack: (val) {
                       setState(() {
                         _currentPage = val;
-                        _pageController.animateToPage(val,
+                        _pageController.animateToPage(
-                            duration: Duration(milliseconds: 300),
+                          val,
-                            curve: Curves.easeInOut);
+                          duration: Duration(milliseconds: 300),
+                          curve: Curves.easeInOut,
+                        );
                         Navigator.pop(context);
                       });
                     },
@@ -210,7 +213,7 @@ class _FullScreenMediaState extends State<FullScreenMedia>
   }
 
   String getDay(DateTime dateTime) {
-    var now = DateTime.now();
+    final now = DateTime.now();
 
     if (DateTime(dateTime.year, dateTime.month, dateTime.day) ==
         DateTime(now.year, now.month, now.day)) {
@@ -238,11 +241,11 @@ class VideoPackage {
   final bool _showControls;
   final bool _autoInitialize;
   final VideoPlayerController _videoPlayerController;
-  ChewieController _chewieController;
+  ChewieController? _chewieController;
 
   VideoPlayerController get videoPlayer => _videoPlayerController;
 
-  ChewieController get chewieController => _chewieController;
+  ChewieController? get chewieController => _chewieController;
 
   bool get initialized => _videoPlayerController.value.isInitialized;
 
@@ -250,12 +253,11 @@ class VideoPackage {
     Attachment attachment, {
     bool showControls = false,
     bool autoInitialize = true,
-  })  : assert(attachment != null),
+  })  : _showControls = showControls,
-        _showControls = showControls,
         _autoInitialize = autoInitialize,
         _videoPlayerController = attachment.localUri != null
-            ? VideoPlayerController.file(File.fromUri(attachment.localUri))
+            ? VideoPlayerController.file(File.fromUri(attachment.localUri!))
-            : VideoPlayerController.network(attachment.assetUrl);
+            : VideoPlayerController.network(attachment.assetUrl!);
 
   Future<void> initialize() {
     return _videoPlayerController.initialize().then((_) {
@@ -278,6 +280,6 @@ class VideoPackage {
 
   Future<void> dispose() {
     _chewieController?.dispose();
-    return _videoPlayerController?.dispose();
+    return _videoPlayerController.dispose();
   }
 }

packages/stream_chat_flutter/lib/src/group_image.dart

@@ -5,8 +5,8 @@ import '../stream_chat_flutter.dart';
 
 class GroupImage extends StatelessWidget {
   const GroupImage({
-    Key key,
+    Key? key,
-    @required this.images,
+    required this.images,
     this.constraints,
     this.onTap,
     this.borderRadius,
@@ -15,12 +15,12 @@ class GroupImage extends StatelessWidget {
     this.selectionThickness = 4,
   }) : super(key: key);
 
-  final List<String> images;
+  final List<String?> images;
-  final BoxConstraints constraints;
+  final BoxConstraints? constraints;
-  final VoidCallback onTap;
+  final VoidCallback? onTap;
   final bool selected;
-  final BorderRadius borderRadius;
+  final BorderRadius? borderRadius;
-  final Color selectionColor;
+  final Color? selectionColor;
   final double selectionThickness;
 
   @override
@@ -35,13 +35,13 @@ class GroupImage extends StatelessWidget {
             StreamChatTheme.of(context)
                 .ownMessageTheme
                 .avatarTheme
-                .borderRadius,
+                ?.borderRadius,
         child: Container(
           constraints: constraints ??
               StreamChatTheme.of(context)
                   .ownMessageTheme
                   .avatarTheme
-                  .constraints,
+                  ?.constraints,
           decoration: BoxDecoration(
             color: StreamChatTheme.of(context).colorTheme.accentBlue,
           ),
@@ -64,7 +64,7 @@ class GroupImage extends StatelessWidget {
                               child: Transform.scale(
                                 scale: 1.2,
                                 child: CachedNetworkImage(
-                                  imageUrl: url,
+                                  imageUrl: url!,
                                   fit: BoxFit.cover,
                                 ),
                               ),
@@ -89,7 +89,7 @@ class GroupImage extends StatelessWidget {
                                 child: Transform.scale(
                                   scale: 1.2,
                                   child: CachedNetworkImage(
-                                    imageUrl: url,
+                                    imageUrl: url!,
                                     fit: BoxFit.cover,
                                   ),
                                 ),
@@ -107,7 +107,8 @@ class GroupImage extends StatelessWidget {
     if (selected) {
       avatar = ClipRRect(
         borderRadius: (borderRadius ??
-                streamChatTheme.ownMessageTheme.avatarTheme.borderRadius) +
+                streamChatTheme.ownMessageTheme.avatarTheme?.borderRadius ??
+                BorderRadius.zero) +
             BorderRadius.circular(selectionThickness),
         child: Container(
           color: selectionColor ??

packages/stream_chat_flutter/lib/src/image_footer.dart

@@ -5,8 +5,8 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:dio/dio.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
-import 'package:share_plus/share_plus.dart';
 import 'package:path_provider/path_provider.dart';
+import 'package:share_plus/share_plus.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/src/video_thumbnail_image.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
@@ -15,13 +15,13 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 class ImageFooter extends StatefulWidget implements PreferredSizeWidget {
   /// Callback to call when pressing the back button.
   /// By default it calls [Navigator.pop]
-  final VoidCallback onBackPressed;
+  final VoidCallback? onBackPressed;
 
   /// Callback to call when the header is tapped.
-  final VoidCallback onTitleTap;
+  final VoidCallback? onTitleTap;
 
   /// Callback to call when the image is tapped.
-  final VoidCallback onImageTap;
+  final VoidCallback? onImageTap;
 
   final int currentPage;
   final int totalPages;
@@ -29,18 +29,18 @@ class ImageFooter extends StatefulWidget implements PreferredSizeWidget {
   final List<Attachment> mediaAttachments;
   final Message message;
 
-  final ValueChanged<int> mediaSelectedCallBack;
+  final ValueChanged<int>? mediaSelectedCallBack;
 
   /// Creates a channel header
   ImageFooter({
-    Key key,
+    Key? key,
+    required this.message,
     this.onBackPressed,
     this.onTitleTap,
     this.onImageTap,
     this.currentPage = 0,
     this.totalPages = 0,
-    this.mediaAttachments,
+    this.mediaAttachments = const [],
-    this.message,
     this.mediaSelectedCallBack,
   })  : preferredSize = Size.fromHeight(kToolbarHeight),
         super(key: key);
@@ -53,14 +53,11 @@ class ImageFooter extends StatefulWidget implements PreferredSizeWidget {
 }
 
 class _ImageFooterState extends State<ImageFooter> {
-  TextEditingController _searchController;
   final TextEditingController _messageController = TextEditingController();
   final FocusNode _messageFocusNode = FocusNode();
 
   final List<Channel> _selectedChannels = [];
 
-  Function modalSetStateCallback;
-
   @override
   void initState() {
     super.initState();
@@ -69,13 +66,6 @@ class _ImageFooterState extends State<ImageFooter> {
     });
   }
 
-  @override
-  void dispose() {
-    _searchController?.clear();
-    _searchController?.dispose();
-    super.dispose();
-  }
-
   @override
   Widget build(BuildContext context) {
     final showShareButton = !kIsWeb;
@@ -106,10 +96,10 @@ class _ImageFooterState extends State<ImageFooter> {
                             widget.mediaAttachments[widget.currentPage];
                         final url = attachment.imageUrl ??
                             attachment.assetUrl ??
-                            attachment.thumbUrl;
+                            attachment.thumbUrl!;
                         final type = attachment.type == 'image'
                             ? 'jpg'
-                            : url?.split('?')?.first?.split('.')?.last ?? 'jpg';
+                            : url.split('?').first.split('.').last;
                         final request =
                             await HttpClient().getUrl(Uri.parse(url));
                         final response = await request.close();
@@ -227,7 +217,7 @@ class _ImageFooterState extends State<ImageFooter> {
                         final attachment = widget.mediaAttachments[index];
                         if (attachment.type == 'video') {
                           media = InkWell(
-                            onTap: () => widget.mediaSelectedCallBack(index),
+                            onTap: () => widget.mediaSelectedCallBack!(index),
                             child: FittedBox(
                               fit: BoxFit.cover,
                               child: VideoThumbnailImage(
@@ -238,13 +228,13 @@ class _ImageFooterState extends State<ImageFooter> {
                           );
                         } else {
                           media = InkWell(
-                            onTap: () => widget.mediaSelectedCallBack(index),
+                            onTap: () => widget.mediaSelectedCallBack!(index),
                             child: AspectRatio(
                               aspectRatio: 1.0,
                               child: CachedNetworkImage(
                                 imageUrl: attachment.imageUrl ??
                                     attachment.assetUrl ??
-                                    attachment.thumbUrl,
+                                    attachment.thumbUrl!,
                                 fit: BoxFit.cover,
                               ),
                             ),
@@ -254,32 +244,33 @@ class _ImageFooterState extends State<ImageFooter> {
                         return Stack(
                           children: [
                             media,
-                            Padding(
+                            if (widget.message.user != null)
-                              padding: EdgeInsets.all(8.0),
+                              Padding(
-                              child: Container(
+                                padding: EdgeInsets.all(8.0),
-                                clipBehavior: Clip.antiAlias,
+                                child: Container(
-                                decoration: BoxDecoration(
+                                  clipBehavior: Clip.antiAlias,
-                                  shape: BoxShape.circle,
+                                  decoration: BoxDecoration(
-                                  color: Colors.white.withOpacity(0.6),
+                                    shape: BoxShape.circle,
-                                  boxShadow: [
+                                    color: Colors.white.withOpacity(0.6),
-                                    BoxShadow(
+                                    boxShadow: [
-                                      blurRadius: 8.0,
+                                      BoxShadow(
-                                      color: StreamChatTheme.of(context)
+                                        blurRadius: 8.0,
-                                          .colorTheme
+                                        color: StreamChatTheme.of(context)
-                                          .black
+                                            .colorTheme
-                                          .withOpacity(0.3),
+                                            .black
-                                    ),
+                                            .withOpacity(0.3),
-                                  ],
+                                      ),
-                                ),
+                                    ],
-                                padding: const EdgeInsets.all(2),
+                                  ),
-                                child: UserAvatar(
+                                  padding: const EdgeInsets.all(2),
-                                  user: widget.message.user,
+                                  child: UserAvatar(
-                                  constraints:
+                                    user: widget.message.user!,
-                                      BoxConstraints.tight(Size(24, 24)),
+                                    constraints:
-                                  showOnlineStatus: false,
+                                        BoxConstraints.tight(Size(24, 24)),
+                                    showOnlineStatus: false,
+                                  ),
                                 ),
                               ),
-                            ),
                           ],
                         );
                       },
@@ -302,7 +293,7 @@ class _ImageFooterState extends State<ImageFooter> {
 
     _messageController.clear();
 
-    for (var channel in _selectedChannels) {
+    for (final channel in _selectedChannels) {
       final message = Message(
         text: text,
         attachments: [attachments[widget.currentPage]],

packages/stream_chat_flutter/lib/src/image_group.dart

@@ -1,23 +1,23 @@
 import 'package:flutter/material.dart';
-import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'package:stream_chat_flutter/src/full_screen_media.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
+import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 class ImageGroup extends StatelessWidget {
   const ImageGroup({
-    Key key,
+    Key? key,
-    @required this.images,
+    required this.images,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
-    @required this.size,
+    required this.size,
     this.onShowMessage,
   }) : super(key: key);
 
   final List<Attachment> images;
   final Message message;
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
   final Size size;
-  final ShowMessageCallback onShowMessage;
+  final ShowMessageCallback? onShowMessage;
 
   @override
   Widget build(BuildContext context) {
@@ -106,9 +106,9 @@ class ImageGroup extends StatelessWidget {
   }
 
   void _onTap(
-    BuildContext context, [
+    BuildContext context,
     int index,
-  ]) {
+  ) {
     final channel = StreamChannel.of(context).channel;
 
     Navigator.push(
@@ -119,8 +119,7 @@ class ImageGroup extends StatelessWidget {
           child: FullScreenMedia(
             mediaAttachments: images,
             startIndex: index,
-            userName: message.user.name,
+            userName: message.user?.name,
-            sentAt: message.createdAt,
             message: message,
             onShowMessage: onShowMessage,
           ),

packages/stream_chat_flutter/lib/src/image_header.dart

@@ -11,16 +11,16 @@ class ImageHeader extends StatelessWidget implements PreferredSizeWidget {
 
   /// Callback to call when pressing the back button.
   /// By default it calls [Navigator.pop]
-  final VoidCallback onBackPressed;
+  final VoidCallback? onBackPressed;
 
   /// Callback to call when pressing the show message button.
-  final VoidCallback onShowMessage;
+  final VoidCallback? onShowMessage;
 
   /// Callback to call when the header is tapped.
-  final VoidCallback onTitleTap;
+  final VoidCallback? onTitleTap;
 
   /// Callback to call when the image is tapped.
-  final VoidCallback onImageTap;
+  final VoidCallback? onImageTap;
 
   final Message message;
 
@@ -32,9 +32,9 @@ class ImageHeader extends StatelessWidget implements PreferredSizeWidget {
 
   /// Creates a channel header
   ImageHeader({
-    Key key,
+    Key? key,
-    this.message,
+    required this.message,
-    this.urls,
+    this.urls = const [],
     this.currentIndex,
     this.showBackButton = true,
     this.onBackPressed,
@@ -109,7 +109,7 @@ class ImageHeader extends StatelessWidget implements PreferredSizeWidget {
   void _showMessageActionModalBottomSheet(BuildContext context) async {
     final channel = StreamChannel.of(context).channel;
 
-    var result = await showDialog(
+    final result = await showDialog(
       context: context,
       barrierColor: StreamChatTheme.of(context).colorTheme.overlay,
       builder: (context) {

packages/stream_chat_flutter/lib/src/info_tile.dart

@@ -6,15 +6,15 @@ class InfoTile extends StatelessWidget {
   final String message;
   final Widget child;
   final bool showMessage;
-  final Alignment tileAnchor;
+  final Alignment? tileAnchor;
-  final Alignment childAnchor;
+  final Alignment? childAnchor;
-  final TextStyle textStyle;
+  final TextStyle? textStyle;
-  final Color backgroundColor;
+  final Color? backgroundColor;
 
   InfoTile({
-    this.message,
+    required this.message,
-    this.child,
+    required this.child,
-    this.showMessage,
+    required this.showMessage,
     this.tileAnchor,
     this.childAnchor,
     this.textStyle,

packages/stream_chat_flutter/lib/src/media_list_view.dart

@@ -21,10 +21,10 @@ extension on Duration {
 
 class MediaListView extends StatefulWidget {
   final List<String> selectedIds;
-  final void Function(AssetEntity media) onSelect;
+  final void Function(AssetEntity media)? onSelect;
 
   const MediaListView({
-    Key key,
+    Key? key,
     this.selectedIds = const [],
     this.onSelect,
   }) : super(key: key);
@@ -58,7 +58,7 @@ class _MediaListViewState extends State<MediaListView> {
             child: InkWell(
               onTap: () {
                 if (widget.onSelect != null) {
-                  widget.onSelect(media);
+                  widget.onSelect!(media);
                 }
               },
               child: Stack(
@@ -147,7 +147,7 @@ class _MediaListViewState extends State<MediaListView> {
     final assetList = await PhotoManager.getAssetPathList(
       hasAll: true,
     ).then((value) {
-      if (value?.isNotEmpty == true) {
+      if (value.isNotEmpty == true) {
         return value.singleWhere((element) => element.isAll);
       }
     });
@@ -169,29 +169,29 @@ class _MediaListViewState extends State<MediaListView> {
 
 class MediaThumbnailProvider extends ImageProvider<MediaThumbnailProvider> {
   const MediaThumbnailProvider({
-    @required this.media,
+    required this.media,
-  }) : assert(media != null);
+  });
 
   final AssetEntity media;
 
   @override
   ImageStreamCompleter load(key, decode) {
     return MultiFrameImageStreamCompleter(
-      codec: _loadAsync(key, decode),
+      codec: _loadAsync(key, decode) as Future<ui.Codec>,
       scale: 1.0,
       informationCollector: () sync* {
-        yield ErrorDescription('Id: ${media?.id}');
+        yield ErrorDescription('Id: ${media.id}');
       },
     );
   }
 
-  Future<ui.Codec> _loadAsync(
+  Future<ui.Codec?> _loadAsync(
       MediaThumbnailProvider key, DecoderCallback decode) async {
     assert(key == this);
     final bytes = await media.thumbData;
     if (bytes?.isNotEmpty != true) return null;
 
-    return await decode(bytes);
+    return await decode(bytes!);
   }
 
   @override
@@ -203,12 +203,12 @@ class MediaThumbnailProvider extends ImageProvider<MediaThumbnailProvider> {
   bool operator ==(dynamic other) {
     if (other.runtimeType != runtimeType) return false;
     final MediaThumbnailProvider typedOther = other;
-    return media?.id == typedOther.media?.id;
+    return media.id == typedOther.media.id;
   }
 
   @override
-  int get hashCode => media?.id?.hashCode ?? 0;
+  int get hashCode => media.id.hashCode;
 
   @override
-  String toString() => '$runtimeType("${media?.id}")';
+  String toString() => '$runtimeType("${media.id}")';
 }

packages/stream_chat_flutter/lib/src/mention_tile.dart

@@ -9,16 +9,16 @@ class MentionTile extends StatelessWidget {
   final Member member;
 
   /// Widget to display as title
-  final Widget title;
+  final Widget? title;
 
   /// Widget to display below [title]
-  final Widget subtitle;
+  final Widget? subtitle;
 
   /// Widget at the start of the tile
-  final Widget leading;
+  final Widget? leading;
 
   /// Widget at the end of tile
-  final Widget trailing;
+  final Widget? trailing;
 
   MentionTile(
     this.member, {
@@ -46,7 +46,7 @@ class MentionTile extends StatelessWidget {
                     40,
                   ),
                 ),
-                user: member.user,
+                user: member.user!,
               ),
           SizedBox(
             width: 8.0,
@@ -60,7 +60,7 @@ class MentionTile extends StatelessWidget {
                 children: [
                   title ??
                       Text(
-                        '${member.user.name}',
+                        '${member.user!.name}',
                         maxLines: 1,
                         overflow: TextOverflow.ellipsis,
                         style: StreamChatTheme.of(context).textTheme.bodyBold,
@@ -87,7 +87,10 @@ class MentionTile extends StatelessWidget {
           ),
           trailing ??
               Padding(
-                padding: const EdgeInsets.only(right: 18.0, left: 8.0),
+                padding: const EdgeInsets.only(
+                  right: 18.0,
+                  left: 8.0,
+                ),
                 child: StreamSvgIcon.mentions(
                   color: StreamChatTheme.of(context).colorTheme.accentBlue,
                 ),

packages/stream_chat_flutter/lib/src/message_action.dart

@@ -4,13 +4,13 @@ import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 /// Class describing a message action
 class MessageAction {
   /// leading widget
-  final Widget leading;
+  final Widget? leading;
 
   /// title widget
-  final Widget title;
+  final Widget? title;
 
   /// callback called on tap
-  final OnMessageTap onTap;
+  final OnMessageTap? onTap;
 
   /// returns a new instance of a [MessageAction]
   MessageAction({

packages/stream_chat_flutter/lib/src/message_actions_modal.dart

@@ -16,13 +16,13 @@ import 'stream_chat.dart';
 import 'stream_chat_theme.dart';
 
 class MessageActionsModal extends StatefulWidget {
-  final Widget Function(BuildContext, Message) editMessageInputBuilder;
+  final Widget Function(BuildContext, Message)? editMessageInputBuilder;
-  final OnMessageTap onThreadReplyTap;
+  final OnMessageTap? onThreadReplyTap;
-  final OnMessageTap onReplyTap;
+  final OnMessageTap? onReplyTap;
   final Message message;
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
   final bool showReactions;
-  final OnMessageTap onCopyTap;
+  final OnMessageTap? onCopyTap;
   final bool showDeleteMessage;
   final bool showCopyMessage;
   final bool showEditMessage;
@@ -31,18 +31,18 @@ class MessageActionsModal extends StatefulWidget {
   final bool showThreadReplyMessage;
   final bool showFlagButton;
   final bool reverse;
-  final ShapeBorder messageShape;
+  final ShapeBorder? messageShape;
-  final ShapeBorder attachmentShape;
+  final ShapeBorder? attachmentShape;
   final DisplayWidget showUserAvatar;
-  final BorderRadius attachmentBorderRadiusGeometry;
+  final BorderRadius? attachmentBorderRadiusGeometry;
 
   /// List of custom actions
   final List<MessageAction> customActions;
 
   const MessageActionsModal({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.showReactions = true,
     this.showDeleteMessage = true,
     this.showEditMessage = true,
@@ -80,24 +80,26 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
     final user = StreamChat.of(context).user;
 
     final roughMaxSize = 2 * size.width / 3;
-    var messageTextLength = widget.message.text.length;
+    var messageTextLength = widget.message.text!.length;
     if (widget.message.quotedMessage != null) {
-      var quotedMessageLength = widget.message.quotedMessage.text.length + 40;
+      var quotedMessageLength =
-      if (widget.message.quotedMessage.attachments?.isNotEmpty == true) {
+          (widget.message.quotedMessage!.text?.length ?? 0) + 40;
+      if (widget.message.quotedMessage!.attachments.isNotEmpty) {
         quotedMessageLength += 40;
       }
       if (quotedMessageLength > messageTextLength) {
         messageTextLength = quotedMessageLength;
       }
     }
-    final roughSentenceSize =
+    final roughSentenceSize = messageTextLength *
-        messageTextLength * widget.messageTheme.messageText.fontSize * 1.2;
+        (widget.messageTheme?.messageText?.fontSize ?? 1) *
-    final divFactor = widget.message.attachments?.isNotEmpty == true
+        1.2;
+    final divFactor = widget.message.attachments.isNotEmpty == true
         ? 1
         : (roughSentenceSize == 0 ? 1 : (roughSentenceSize / roughMaxSize));
 
     final hasFileAttachment =
-        widget.message.attachments?.any((it) => it.type == 'file') == true;
+        widget.message.attachments.any((it) => it.type == 'file') == true;
 
     return GestureDetector(
       behavior: HitTestBehavior.translucent,
@@ -134,11 +136,10 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                           children: <Widget>[
                             if (widget.showReactions &&
                                 (widget.message.status ==
-                                        MessageSendingStatus.sent ||
+                                    MessageSendingStatus.sent))
-                                    widget.message.status == null))
                               Align(
                                 alignment: Alignment(
-                                    user.id == widget.message.user.id
+                                    user?.id == widget.message.user?.id
                                         ? (divFactor > 1.0
                                             ? 0.0
                                             : (1.0 - divFactor))
@@ -159,8 +160,8 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                                 attachmentBorderRadiusGeometry:
                                     widget.attachmentBorderRadiusGeometry,
                                 message: widget.message.copyWith(
-                                  text: widget.message.text.length > 200
+                                  text: widget.message.text!.length > 200
-                                      ? '${widget.message.text.substring(0, 200)}...'
+                                      ? '${widget.message.text!.substring(0, 200)}...'
                                       : widget.message.text,
                                 ),
                                 messageTheme: widget.messageTheme,
@@ -177,15 +178,14 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                                 padding: const EdgeInsets.all(0),
                                 textPadding: EdgeInsets.symmetric(
                                   vertical: 8.0,
-                                  horizontal: widget.message.text.isOnlyEmoji
+                                  horizontal: widget.message.text!.isOnlyEmoji
                                       ? 0
                                       : 16.0,
                                 ),
                                 showReactionPickerIndicator:
                                     widget.showReactions &&
                                         (widget.message.status ==
-                                                MessageSendingStatus.sent ||
+                                            MessageSendingStatus.sent),
-                                            widget.message.status == null),
                                 showInChannelIndicator: false,
                                 showSendingIndicator: false,
                                 shape: widget.messageShape,
@@ -212,14 +212,12 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                                         CrossAxisAlignment.stretch,
                                     children: [
                                       if (widget.showReplyMessage &&
-                                              widget.message.status ==
+                                          widget.message.status ==
-                                                  MessageSendingStatus.sent ||
+                                              MessageSendingStatus.sent)
-                                          widget.message.status == null)
                                         _buildReplyButton(context),
                                       if (widget.showThreadReplyMessage &&
                                           (widget.message.status ==
-                                                  MessageSendingStatus.sent ||
+                                              MessageSendingStatus.sent) &&
-                                              widget.message.status == null) &&
                                           widget.message.parentId == null)
                                         _buildThreadReplyButton(context),
                                       if (widget.showResendMessage)
@@ -315,7 +313,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
           okText: 'OK',
         );
       } catch (err) {
-        if (json.decode(err?.body ?? {})['code'] == 4) {
+        if (err is ApiError && json.decode(err.body ?? '{}')['code'] == 4) {
           await showInfoDialog(
             context,
             icon: StreamSvgIcon.flag(
@@ -337,7 +335,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
     setState(() {
       _showActions = false;
     });
-    var answer = await showConfirmationDialog(
+    final answer = await showConfirmationDialog(
       context,
       title: 'Delete message',
       icon: StreamSvgIcon.flag(
@@ -349,7 +347,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
       cancelText: 'CANCEL',
     );
 
-    if (answer) {
+    if (answer == true) {
       try {
         Navigator.pop(context);
         await StreamChannel.of(context).channel.deleteMessage(widget.message);
@@ -381,7 +379,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
       onTap: () {
         Navigator.pop(context);
         if (widget.onReplyTap != null) {
-          widget.onReplyTap(widget.message);
+          widget.onReplyTap!(widget.message);
         }
       },
       child: Padding(
@@ -578,7 +576,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
                 ),
               ),
               widget.editMessageInputBuilder != null
-                  ? widget.editMessageInputBuilder(context, widget.message)
+                  ? widget.editMessageInputBuilder!(context, widget.message)
                   : MessageInput(
                       editMessage: widget.message,
                       preMessageSending: (m) {
@@ -599,7 +597,7 @@ class _MessageActionsModalState extends State<MessageActionsModal> {
       onTap: () {
         Navigator.pop(context);
         if (widget.onThreadReplyTap != null) {
-          widget.onThreadReplyTap(widget.message);
+          widget.onThreadReplyTap!(widget.message);
         }
       },
       child: Padding(

packages/stream_chat_flutter/lib/src/message_input.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:io';
 import 'dart:math';
 
 import 'package:cached_network_image/cached_network_image.dart';
@@ -19,6 +20,7 @@ import 'package:stream_chat_flutter/src/stream_svg_icon.dart';
 import 'package:stream_chat_flutter/src/video_service.dart';
 import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'package:substring_highlight/substring_highlight.dart';
+import 'package:video_compress/video_compress.dart';
 
 import '../stream_chat_flutter.dart';
 import 'attachment/attachment.dart';
@@ -109,7 +111,7 @@ const _kMaxAttachmentSize = 20971520; // 20MB in Bytes
 class MessageInput extends StatefulWidget {
   /// Instantiate a new MessageInput
   MessageInput({
-    Key key,
+    Key? key,
     this.onMessageSent,
     this.preMessageSending,
     this.parentMessage,
@@ -135,20 +137,20 @@ class MessageInput extends StatefulWidget {
   }) : super(key: key);
 
   /// Message to edit
-  final Message editMessage;
+  final Message? editMessage;
 
   /// Message to start with
-  final Message initialMessage;
+  final Message? initialMessage;
 
   /// Function called after sending the message
-  final void Function(Message) onMessageSent;
+  final void Function(Message)? onMessageSent;
 
   /// Function called right before sending the message
   /// Use this to transform the message
-  final FutureOr<Message> Function(Message) preMessageSending;
+  final FutureOr<Message> Function(Message)? preMessageSending;
 
   /// Parent message in case of a thread
-  final Message parentMessage;
+  final Message? parentMessage;
 
   /// Maximum Height for the TextField to grow before it starts scrolling
   final double maxHeight;
@@ -166,25 +168,25 @@ class MessageInput extends StatefulWidget {
   final bool hideSendAsDm;
 
   /// The text controller of the TextField
-  final TextEditingController textEditingController;
+  final TextEditingController? textEditingController;
 
   /// List of action widgets
-  final List<Widget> actions;
+  final List<Widget>? actions;
 
   /// The location of the custom actions
   final ActionsLocation actionsLocation;
 
   /// Map that defines a thumbnail builder for an attachment type
-  final Map<String, AttachmentThumbnailBuilder> attachmentThumbnailBuilders;
+  final Map<String, AttachmentThumbnailBuilder>? attachmentThumbnailBuilders;
 
   /// The focus node associated to the TextField
-  final FocusNode focusNode;
+  final FocusNode? focusNode;
 
   ///
-  final Message quotedMessage;
+  final Message? quotedMessage;
 
   ///
-  final VoidCallback onQuotedMessageCleared;
+  final VoidCallback? onQuotedMessageCleared;
 
   /// The location of the send button
   final SendButtonLocation sendButtonLocation;
@@ -193,20 +195,20 @@ class MessageInput extends StatefulWidget {
   final bool autofocus;
 
   /// Send button widget in an idle state
-  final Widget idleSendButton;
+  final Widget? idleSendButton;
 
   /// Send button widget in an active state
-  final Widget activeSendButton;
+  final Widget? activeSendButton;
 
   /// Customize the tile for the mentions overlay
-  final MentionTileBuilder mentionsTileBuilder;
+  final MentionTileBuilder? mentionsTileBuilder;
 
   @override
   MessageInputState createState() => MessageInputState();
 
   /// Use this method to get the current [StreamChatState] instance
   static MessageInputState of(BuildContext context) {
-    MessageInputState messageInputState;
+    MessageInputState? messageInputState;
 
     messageInputState = context.findAncestorStateOfType<MessageInputState>();
 
@@ -224,15 +226,15 @@ class MessageInputState extends State<MessageInput> {
   final List<User> _mentionedUsers = [];
 
   final _imagePicker = ImagePicker();
-  FocusNode _focusNode;
+  late final FocusNode _focusNode;
   bool _inputEnabled = true;
   bool _messageIsPresent = false;
   bool _animateContainer = true;
   bool _commandEnabled = false;
-  OverlayEntry _commandsOverlay, _mentionsOverlay, _emojiOverlay;
+  OverlayEntry? _commandsOverlay, _mentionsOverlay, _emojiOverlay;
-  Iterable<String> _emojiNames;
+  late Iterable<String> _emojiNames;
 
-  Command _chosenCommand;
+  Command? _chosenCommand;
   bool _actionsShrunk = false;
   bool _sendAsDm = false;
   bool _openFilePickerSection = false;
@@ -242,7 +244,7 @@ class MessageInputState extends State<MessageInput> {
       KeyboardVisibilityController();
 
   /// The editing controller passed to the input TextField
-  TextEditingController textEditingController;
+  late final TextEditingController textEditingController;
 
   bool get _hasQuotedMessage => widget.quotedMessage != null;
 
@@ -250,7 +252,8 @@ class MessageInputState extends State<MessageInput> {
   void initState() {
     super.initState();
     _focusNode = widget.focusNode ?? FocusNode();
-    _emojiNames = Emoji.all().map((e) => e.name);
+    _emojiNames =
+        Emoji.all().where((it) => it.name != null).map((e) => e.name!);
 
     if (!kIsWeb) {
       _keyboardListener =
@@ -264,7 +267,7 @@ class MessageInputState extends State<MessageInput> {
     textEditingController =
         widget.textEditingController ?? TextEditingController();
     if (widget.editMessage != null || widget.initialMessage != null) {
-      _parseExistingMessage(widget.editMessage ?? widget.initialMessage);
+      _parseExistingMessage(widget.editMessage ?? widget.initialMessage!);
     }
 
     textEditingController.addListener(() {
@@ -447,7 +450,7 @@ class MessageInputState extends State<MessageInput> {
       firstChild: sendButton,
       secondChild: widget.idleSendButton ?? _buildIdleSendButton(context),
       duration:
-          StreamChatTheme.of(context).messageInputTheme.sendAnimationDuration,
+          StreamChatTheme.of(context).messageInputTheme.sendAnimationDuration!,
       alignment: Alignment.center,
     );
   }
@@ -490,9 +493,9 @@ class MessageInputState extends State<MessageInput> {
                   widget.editMessage == null &&
                   StreamChannel.of(context)
                           .channel
-                          ?.config
+                          .config
                           ?.commands
-                          ?.isNotEmpty ==
+                          .isNotEmpty ==
                       true)
                 _buildCommandButton(),
               ...widget.actions ?? [],
@@ -571,7 +574,7 @@ class MessageInputState extends State<MessageInput> {
     return InputDecoration(
       isDense: true,
       hintText: _getHint(),
-      hintStyle: theme.messageInputTheme.inputTextStyle.copyWith(
+      hintStyle: theme.messageInputTheme.inputTextStyle!.copyWith(
         color: theme.colorTheme.grey,
       ),
       border: OutlineInputBorder(
@@ -621,7 +624,7 @@ class MessageInputState extends State<MessageInput> {
                           size: 16.0,
                         ),
                         Text(
-                          _chosenCommand?.name?.toUpperCase() ?? '',
+                          _chosenCommand?.name.toUpperCase() ?? '',
                           style: StreamChatTheme.of(context)
                               .textTheme
                               .footnoteBold
@@ -676,9 +679,9 @@ class MessageInputState extends State<MessageInput> {
     ).merge(passedDecoration);
   }
 
-  Timer _debounce;
+  Timer? _debounce;
 
-  String _previousValue;
+  String? _previousValue;
 
   void _onChanged(BuildContext context, String s) {
     if (s == _previousValue) {
@@ -686,14 +689,14 @@ class MessageInputState extends State<MessageInput> {
     }
     _previousValue = s;
 
-    if (_debounce?.isActive == true) _debounce.cancel();
+    if (_debounce?.isActive == true) _debounce!.cancel();
     _debounce = Timer(
       const Duration(milliseconds: 350),
       () {
         if (!mounted) {
           return;
         }
-        StreamChannel.of(context).channel.keyStroke()?.catchError((e) {});
+        StreamChannel.of(context).channel.keyStroke().catchError((e) {});
 
         setState(() {
           _messageIsPresent = s.trim().isNotEmpty;
@@ -721,7 +724,7 @@ class MessageInputState extends State<MessageInput> {
   }
 
   String _getHint() {
-    if (_commandEnabled && _chosenCommand.name == 'giphy') {
+    if (_commandEnabled && _chosenCommand!.name == 'giphy') {
       return 'Search GIFs';
     }
     if (_attachments.isNotEmpty) {
@@ -742,7 +745,7 @@ class MessageInputState extends State<MessageInput> {
       final textToSelection = textEditingController.text
           .substring(0, textEditingController.value.selection.start);
       final splits = textToSelection.split(':');
-      final query = splits[splits.length - 2]?.toLowerCase();
+      final query = splits[splits.length - 2].toLowerCase();
       final emoji = Emoji.byName(query);
 
       if (textToSelection.endsWith(':') && emoji != null) {
@@ -751,7 +754,7 @@ class MessageInputState extends State<MessageInput> {
         _emojiOverlay = _buildEmojiOverlay();
 
         if (_emojiOverlay != null) {
-          Overlay.of(context).insert(_emojiOverlay);
+          Overlay.of(context)!.insert(_emojiOverlay!);
         }
       }
     }
@@ -767,7 +770,7 @@ class MessageInputState extends State<MessageInput> {
             .contains('@')) {
       _mentionsOverlay = _buildMentionsOverlayEntry();
       if (_mentionsOverlay != null) {
-        Overlay.of(context).insert(_mentionsOverlay);
+        Overlay.of(context)!.insert(_mentionsOverlay!);
       }
     }
   }
@@ -778,8 +781,8 @@ class MessageInputState extends State<MessageInput> {
               .channel
               .config
               ?.commands
-              ?.where((element) => element.name == s.substring(1))
+              .where((element) => element.name == s.substring(1))
-              ?.toList() ??
+              .toList() ??
           [];
 
       if (matchedCommandsList.length == 1) {
@@ -789,32 +792,32 @@ class MessageInputState extends State<MessageInput> {
         setState(() {
           _commandEnabled = true;
         });
-        _commandsOverlay.remove();
+        _commandsOverlay!.remove();
         _commandsOverlay = null;
       } else {
         _commandsOverlay = _buildCommandsOverlayEntry();
         if (_commandsOverlay != null) {
-          Overlay.of(context).insert(_commandsOverlay);
+          Overlay.of(context)!.insert(_commandsOverlay!);
         }
       }
     }
   }
 
-  OverlayEntry _buildCommandsOverlayEntry() {
+  OverlayEntry? _buildCommandsOverlayEntry() {
     final text = textEditingController.text.trimLeft();
     final commands = StreamChannel.of(context)
             .channel
             .config
             ?.commands
-            ?.where((c) => c.name.contains(text.replaceFirst('/', '')))
+            .where((c) => c.name.contains(text.replaceFirst('/', '')))
-            ?.toList() ??
+            .toList() ??
         [];
 
     if (commands.isEmpty) {
       return null;
     }
 
-    RenderBox renderBox = context.findRenderObject();
+    final renderBox = context.findRenderObject() as RenderBox;
     final size = renderBox.size;
 
     return OverlayEntry(builder: (context) {
@@ -951,7 +954,6 @@ class MessageInputState extends State<MessageInput> {
                       .colorTheme
                       .black
                       .withOpacity(0.2));
-          break;
         case 1:
           return _attachmentContainsFile
               ? StreamChatTheme.of(context).colorTheme.accentBlue
@@ -964,17 +966,14 @@ class MessageInputState extends State<MessageInput> {
                       .colorTheme
                       .black
                       .withOpacity(0.2));
-          break;
         case 2:
           return _attachmentContainsFile && _attachments.isNotEmpty
               ? StreamChatTheme.of(context).colorTheme.black.withOpacity(0.2)
               : StreamChatTheme.of(context).colorTheme.black.withOpacity(0.5);
-          break;
         case 3:
           return _attachmentContainsFile && _attachments.isNotEmpty
               ? StreamChatTheme.of(context).colorTheme.black.withOpacity(0.2)
               : StreamChatTheme.of(context).colorTheme.black.withOpacity(0.5);
-          break;
         default:
           return Colors.black;
       }
@@ -1106,10 +1105,10 @@ class MessageInputState extends State<MessageInput> {
   }
 
   void _addAttachment(AssetEntity medium) async {
-    final mediaFile = await medium.originFile.timeout(
+    final mediaFile = await (medium.originFile.timeout(
       Duration(seconds: 5),
       onTimeout: () => medium.originFile,
-    );
+    ) as FutureOr<File>);
 
     var file = AttachmentFile(
       path: mediaFile.path,
@@ -1117,11 +1116,12 @@ class MessageInputState extends State<MessageInput> {
       bytes: mediaFile.readAsBytesSync(),
     );
 
-    if (file.size > _kMaxAttachmentSize) {
+    if (file.size! > _kMaxAttachmentSize) {
-      if (medium?.type == AssetType.video) {
+      if (medium.type == AssetType.video) {
-        final mediaInfo = await VideoService.compressVideo(file.path);
+        final mediaInfo = await (VideoService.compressVideo(file.path)
+            as FutureOr<MediaInfo>);
 
-        if (mediaInfo.filesize > _kMaxAttachmentSize) {
+        if (mediaInfo.filesize! > _kMaxAttachmentSize) {
           _showErrorAlert(
             'The file is too large to upload. The file size limit is 20MB. We tried compressing it, but it was not enough.',
           );
@@ -1129,8 +1129,8 @@ class MessageInputState extends State<MessageInput> {
         }
         file = AttachmentFile(
           name: file.name,
-          size: mediaInfo.filesize,
+          size: mediaInfo.filesize!,
-          bytes: await mediaInfo.file.readAsBytes(),
+          bytes: await mediaInfo.file?.readAsBytes(),
           path: mediaInfo.path,
         );
       } else {
@@ -1159,7 +1159,6 @@ class MessageInputState extends State<MessageInput> {
             size: 24.0,
           ),
         );
-        break;
       case 'ban':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1169,7 +1168,6 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
       case 'flag':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1179,7 +1177,6 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
       case 'imgur':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1190,7 +1187,6 @@ class MessageInputState extends State<MessageInput> {
             ),
           ),
         );
-        break;
       case 'mute':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1200,7 +1196,6 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
       case 'unban':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1210,7 +1205,6 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
       case 'unmute':
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1220,7 +1214,6 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
       default:
         return CircleAvatar(
           backgroundColor: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1230,17 +1223,16 @@ class MessageInputState extends State<MessageInput> {
             color: Colors.white,
           ),
         );
-        break;
     }
   }
 
-  OverlayEntry _buildMentionsOverlayEntry() {
+  OverlayEntry? _buildMentionsOverlayEntry() {
     final splits = textEditingController.text
         .substring(0, textEditingController.value.selection.start)
         .split('@');
     final query = splits.last.toLowerCase();
 
-    Future<List<Member>> queryMembers;
+    Future<List<Member>>? queryMembers;
 
     if (query.isNotEmpty) {
       queryMembers = StreamChannel.of(context)
@@ -1249,16 +1241,16 @@ class MessageInputState extends State<MessageInput> {
           .then((res) => res.members);
     }
 
-    final members = StreamChannel.of(context).channel.state.members?.where((m) {
+    final members = StreamChannel.of(context).channel.state?.members.where((m) {
-          return m.user.name.toLowerCase().contains(query);
+          return m.user?.name.toLowerCase().contains(query) == true;
-        })?.toList() ??
+        }).toList() ??
         [];
 
     if (members.isEmpty) {
       return null;
     }
 
-    RenderBox renderBox = context.findRenderObject();
+    final renderBox = context.findRenderObject() as RenderBox;
     final size = renderBox.size;
 
     return OverlayEntry(
@@ -1298,7 +1290,9 @@ class MessageInputState extends State<MessageInput> {
                             SizedBox(
                               height: 8.0,
                             ),
-                            ...snapshot.data.map(
+                            ...snapshot.data!
+                                .where((it) => it.user != null)
+                                .map(
                               (m) {
                                 return Material(
                                   color: StreamChatTheme.of(context)
@@ -1306,9 +1300,11 @@ class MessageInputState extends State<MessageInput> {
                                       .white,
                                   child: InkWell(
                                     onTap: () {
-                                      _mentionedUsers.add(m.user);
+                                      if (m.user != null) {
+                                        _mentionedUsers.add(m.user!);
+                                      }
 
-                                      splits[splits.length - 1] = m.user.name;
+                                      splits[splits.length - 1] = m.user!.name;
                                       final rejoin = splits.join('@');
 
                                       textEditingController.value =
@@ -1321,12 +1317,13 @@ class MessageInputState extends State<MessageInput> {
                                           offset: rejoin.length,
                                         ),
                                       );
-                                      _debounce.cancel();
+                                      _debounce!.cancel();
                                       _mentionsOverlay?.remove();
                                       _mentionsOverlay = null;
                                     },
                                     child: widget.mentionsTileBuilder != null
-                                        ? widget.mentionsTileBuilder(context, m)
+                                        ? widget.mentionsTileBuilder!(
+                                            context, m)
                                         : MentionTile(m),
                                   ),
                                 );
@@ -1349,7 +1346,7 @@ class MessageInputState extends State<MessageInput> {
     );
   }
 
-  OverlayEntry _buildEmojiOverlay() {
+  OverlayEntry? _buildEmojiOverlay() {
     final splits = textEditingController.text
         .substring(0, textEditingController.value.selection.start)
         .split(':');
@@ -1368,7 +1365,7 @@ class MessageInputState extends State<MessageInput> {
       return null;
     }
 
-    RenderBox renderBox = context.findRenderObject();
+    final renderBox = context.findRenderObject() as RenderBox;
     final size = renderBox.size;
 
     return OverlayEntry(builder: (context) {
@@ -1431,19 +1428,20 @@ class MessageInputState extends State<MessageInput> {
                     );
                   }
 
-                  final emoji = emojis.elementAt(i - 1);
+                  final emoji = emojis.elementAt(i - 1)!;
                   return ListTile(
                     title: SubstringHighlight(
-                      text: "${emoji.char} ${emoji.name.replaceAll('_', ' ')}",
+                      text: "${emoji.char} ${emoji.name!.replaceAll('_', ' ')}",
                       term: query,
                       textStyleHighlight:
-                          Theme.of(context).textTheme.headline6.copyWith(
+                          Theme.of(context).textTheme.headline6!.copyWith(
                                 fontSize: 14.5,
                                 fontWeight: FontWeight.bold,
                               ),
-                      textStyle: Theme.of(context).textTheme.headline6.copyWith(
+                      textStyle:
-                            fontSize: 14.5,
+                          Theme.of(context).textTheme.headline6!.copyWith(
-                          ),
+                                fontSize: 14.5,
+                              ),
                     ),
                     onTap: () {
                       _chooseEmoji(splits, emoji);
@@ -1457,7 +1455,7 @@ class MessageInputState extends State<MessageInput> {
   }
 
   void _chooseEmoji(List<String> splits, Emoji emoji) {
-    final rejoin = splits.sublist(0, splits.length - 1).join(':') + emoji.char;
+    final rejoin = splits.sublist(0, splits.length - 1).join(':') + emoji.char!;
 
     textEditingController.value = TextEditingValue(
       text: rejoin +
@@ -1485,8 +1483,8 @@ class MessageInputState extends State<MessageInput> {
 
   Widget _buildReplyToMessage() {
     if (!_hasQuotedMessage) return Offstage();
-    final containsUrl = widget.quotedMessage.attachments
+    final containsUrl = widget.quotedMessage!.attachments
-            ?.any((element) => element.ogScrapeUrl != null) ==
+            .any((element) => element.ogScrapeUrl != null) ==
         true;
     return Transform(
       transform: Matrix4.rotationY(pi),
@@ -1494,7 +1492,7 @@ class MessageInputState extends State<MessageInput> {
       child: QuotedMessageWidget(
         reverse: true,
         showBorder: !containsUrl,
-        message: widget.quotedMessage,
+        message: widget.quotedMessage!,
         messageTheme: StreamChatTheme.of(context).otherMessageTheme,
         padding: const EdgeInsets.fromLTRB(8, 8, 8, 0),
       ),
@@ -1525,7 +1523,7 @@ class MessageInputState extends State<MessageInput> {
                         borderRadius: BorderRadius.circular(10),
                         clipBehavior: Clip.antiAlias,
                         child: FileAttachment(
-                          message: null,
+                          message: Message(), // dummy message
                           attachment: e,
                           size: Size(
                             MediaQuery.of(context).size.width * 0.65,
@@ -1609,11 +1607,9 @@ class MessageInputState extends State<MessageInput> {
   }
 
   Widget _buildAttachment(Attachment attachment) {
-    if (attachment == null) return Offstage();
-
     if (widget.attachmentThumbnailBuilders?.containsKey(attachment.type) ==
         true) {
-      return widget.attachmentThumbnailBuilders[attachment.type](
+      return widget.attachmentThumbnailBuilders![attachment.type!]!(
         context,
         attachment,
       );
@@ -1624,7 +1620,7 @@ class MessageInputState extends State<MessageInput> {
       case 'giphy':
         return attachment.file != null
             ? Image.memory(
-                attachment.file.bytes,
+                attachment.file!.bytes!,
                 fit: BoxFit.cover,
                 errorBuilder: (context, _, __) {
                   return Image.asset(
@@ -1636,10 +1632,11 @@ class MessageInputState extends State<MessageInput> {
             : CachedNetworkImage(
                 imageUrl: attachment.imageUrl ??
                     attachment.assetUrl ??
-                    attachment.thumbUrl,
+                    attachment.thumbUrl!,
                 fit: BoxFit.cover,
                 errorWidget: (_, obj, trace) {
-                  return getFileTypeImage(attachment.extraData['other']);
+                  return getFileTypeImage(
+                      attachment.extraData['other'] as String?);
                 },
                 progressIndicatorBuilder: (context, _, progress) {
                   return Shimmer.fromColors(
@@ -1717,7 +1714,7 @@ class MessageInputState extends State<MessageInput> {
           setState(() {
             _commandsOverlay = _buildCommandsOverlayEntry();
             if (_commandsOverlay != null) {
-              Overlay.of(context).insert(_commandsOverlay);
+              Overlay.of(context)!.insert(_commandsOverlay!);
             }
           });
         } else {
@@ -1852,7 +1849,7 @@ class MessageInputState extends State<MessageInput> {
   void addAttachment(Attachment attachment) {
     setState(() {
       _attachments[attachment.id] = attachment.copyWith(
-        uploadState: attachment.uploadState ?? UploadState.success(),
+        uploadState: attachment.uploadState,
       );
     });
   }
@@ -1862,8 +1859,8 @@ class MessageInputState extends State<MessageInput> {
   void pickFile(DefaultAttachmentTypes fileType, [bool camera = false]) async {
     setState(() => _inputEnabled = false);
 
-    AttachmentFile file;
+    AttachmentFile? file;
-    String attachmentType;
+    String? attachmentType;
 
     if (fileType == DefaultAttachmentTypes.image) {
       attachmentType = 'image';
@@ -1874,7 +1871,7 @@ class MessageInputState extends State<MessageInput> {
     }
 
     if (camera) {
-      PickedFile pickedFile;
+      PickedFile? pickedFile;
       if (fileType == DefaultAttachmentTypes.image) {
         pickedFile = await _imagePicker.getImage(source: ImageSource.camera);
       } else if (fileType == DefaultAttachmentTypes.video) {
@@ -1890,7 +1887,7 @@ class MessageInputState extends State<MessageInput> {
         bytes: bytes,
       );
     } else {
-      FileType type;
+      late FileType type;
       if (fileType == DefaultAttachmentTypes.image) {
         type = FileType.image;
       } else if (fileType == DefaultAttachmentTypes.video) {
@@ -1902,8 +1899,8 @@ class MessageInputState extends State<MessageInput> {
         type: type,
         withData: true,
       );
-      if (res?.files?.isNotEmpty == true) {
+      if (res?.files.isNotEmpty == true) {
-        file = res.files.single.toAttachmentFile;
+        file = res!.files.single.toAttachmentFile;
       }
     }
 
@@ -1911,29 +1908,28 @@ class MessageInputState extends State<MessageInput> {
 
     if (file == null) return;
 
-    final mimeType = file.name?.mimeType ?? file.path.split('/').last.mimeType;
+    final mimeType = file.name?.mimeType ?? file.path!.split('/').last.mimeType;
 
-    final extraDataMap = <String, dynamic>{};
+    final extraDataMap = <String, Object>{};
 
     if (mimeType?.subtype != null) {
-      extraDataMap['mime_type'] = mimeType.subtype.toLowerCase();
+      extraDataMap['mime_type'] = mimeType!.subtype.toLowerCase();
     }
 
-    if (file.size != null) {
+    extraDataMap['file_size'] = file.size!;
-      extraDataMap['file_size'] = file.size;
-    }
 
     final attachment = Attachment(
       file: file,
       type: attachmentType,
-      extraData: extraDataMap.isNotEmpty ? extraDataMap : null,
+      extraData: extraDataMap,
     );
 
-    if (file.size > _kMaxAttachmentSize) {
+    if (file.size! > _kMaxAttachmentSize) {
       if (attachmentType == 'Video') {
-        final mediaInfo = await VideoService.compressVideo(file.path);
+        final mediaInfo = await (VideoService.compressVideo(file.path)
+            as FutureOr<MediaInfo>);
 
-        if (mediaInfo.filesize > _kMaxAttachmentSize) {
+        if (mediaInfo.filesize! > _kMaxAttachmentSize) {
           _showErrorAlert(
             'The file is too large to upload. The file size limit is 20MB. We tried compressing it, but it was not enough.',
           );
@@ -1941,8 +1937,8 @@ class MessageInputState extends State<MessageInput> {
         }
         file = AttachmentFile(
           name: file.name,
-          size: mediaInfo.filesize,
+          size: mediaInfo.filesize!,
-          bytes: await mediaInfo.file.readAsBytes(),
+          bytes: await mediaInfo.file!.readAsBytes(),
           path: mediaInfo.path,
         );
       } else {
@@ -1959,7 +1955,8 @@ class MessageInputState extends State<MessageInput> {
       _attachments.update(attachment.id, (it) {
         return it.copyWith(
           file: file,
-          extraData: {...it.extraData}..update('file_size', (_) => file.size),
+          extraData: {...it.extraData}
+            ..update('file_size', ((_) => file!.size!)),
         );
       });
     });
@@ -2023,7 +2020,7 @@ class MessageInputState extends State<MessageInput> {
     final shouldUnfocus = _commandEnabled;
 
     if (_commandEnabled) {
-      text = '/${_chosenCommand.name} ' + text;
+      text = '/${_chosenCommand!.name} ' + text;
     }
 
     final attachments = [..._attachments.values];
@@ -2031,7 +2028,7 @@ class MessageInputState extends State<MessageInput> {
     textEditingController.clear();
     _attachments.clear();
     if (widget.onQuotedMessageCleared != null) {
-      widget.onQuotedMessageCleared();
+      widget.onQuotedMessageCleared!();
     }
 
     setState(() {
@@ -2047,7 +2044,7 @@ class MessageInputState extends State<MessageInput> {
     Future sendingFuture;
     Message message;
     if (widget.editMessage != null) {
-      message = widget.editMessage.copyWith(
+      message = widget.editMessage!.copyWith(
         text: text,
         attachments: attachments,
         mentionedUsers:
@@ -2066,25 +2063,25 @@ class MessageInputState extends State<MessageInput> {
 
     if (widget.quotedMessage != null) {
       message = message.copyWith(
-        quotedMessageId: widget.quotedMessage.id,
+        quotedMessageId: widget.quotedMessage!.id,
       );
     }
 
     if (widget.preMessageSending != null) {
-      message = await widget.preMessageSending(message);
+      message = await widget.preMessageSending!(message);
     }
 
     final streamChannel = StreamChannel.of(context);
     final channel = streamChannel.channel;
-    if (!channel.state.isUpToDate) {
+    if (!channel.state!.isUpToDate) {
       await streamChannel.reloadChannel();
     }
 
     _mentionedUsers.clear();
 
     if (widget.editMessage == null ||
-        widget.editMessage.status == MessageSendingStatus.failed ||
+        widget.editMessage!.status == MessageSendingStatus.failed ||
-        widget.editMessage.status == MessageSendingStatus.sending) {
+        widget.editMessage!.status == MessageSendingStatus.sending) {
       sendingFuture = channel.sendMessage(message);
     } else {
       sendingFuture = channel.updateMessage(message);
@@ -2099,12 +2096,12 @@ class MessageInputState extends State<MessageInput> {
         _parseExistingMessage(message);
       }
       if (widget.onMessageSent != null) {
-        widget.onMessageSent(resp.message);
+        widget.onMessageSent!(resp.message);
       }
     });
   }
 
-  StreamSubscription _keyboardListener;
+  StreamSubscription? _keyboardListener;
 
   void _showErrorAlert(String description) {
     showModalBottomSheet(
@@ -2178,14 +2175,12 @@ class MessageInputState extends State<MessageInput> {
   }
 
   void _parseExistingMessage(Message message) {
-    textEditingController.text = message.text;
+    textEditingController.text = message.text!;
     _messageIsPresent = true;
-    if (message.attachments != null) {
+    for (final attachment in message.attachments) {
-      for (final attachment in message.attachments) {
+      _attachments[attachment.id] = attachment.copyWith(
-        _attachments[attachment.id] = attachment.copyWith(
+        uploadState: attachment.uploadState,
-          uploadState: attachment.uploadState ?? UploadState.success(),
+      );
-        );
-      }
     }
   }
 
@@ -2266,12 +2261,12 @@ class _PickerWidget extends StatefulWidget {
   final void Function(AssetEntity) onMediaSelected;
 
   const _PickerWidget({
-    Key key,
+    Key? key,
-    @required this.filePickerIndex,
+    required this.filePickerIndex,
-    @required this.containsFile,
+    required this.containsFile,
-    @required this.selectedMedias,
+    required this.selectedMedias,
-    @required this.onAddMoreFilesClick,
+    required this.onAddMoreFilesClick,
-    @required this.onMediaSelected,
+    required this.onMediaSelected,
   }) : super(key: key);
 
   @override
@@ -2279,7 +2274,7 @@ class _PickerWidget extends StatefulWidget {
 }
 
 class __PickerWidgetState extends State<_PickerWidget> {
-  Future<bool> requestPermission;
+  Future<bool>? requestPermission;
 
   @override
   void initState() {
@@ -2299,7 +2294,7 @@ class __PickerWidgetState extends State<_PickerWidget> {
             return const Center(child: CircularProgressIndicator());
           }
 
-          if (snapshot.data) {
+          if (snapshot.data!) {
             if (widget.containsFile) {
               return GestureDetector(
                 onTap: () {

packages/stream_chat_flutter/lib/src/message_list_view.dart

@@ -26,14 +26,14 @@ typedef MessageBuilder = Widget Function(
 );
 typedef ParentMessageBuilder = Widget Function(
   BuildContext,
-  Message,
+  Message?,
 );
 typedef SystemMessageBuilder = Widget Function(
   BuildContext,
   Message,
 );
-typedef ThreadBuilder = Widget Function(BuildContext context, Message parent);
+typedef ThreadBuilder = Widget Function(BuildContext context, Message? parent);
-typedef ThreadTapCallback = void Function(Message, Widget);
+typedef ThreadTapCallback = void Function(Message, Widget?);
 
 typedef OnMessageSwiped = void Function(Message);
 typedef OnMessageTap = void Function(Message);
@@ -41,13 +41,13 @@ typedef ReplyTapCallback = void Function(Message);
 
 class MessageDetails {
   /// True if the message belongs to the current user
-  bool isMyMessage;
+  bool? isMyMessage;
 
   /// True if the user message is the same of the previous message
-  bool isLastUser;
+  bool? isLastUser;
 
   /// True if the user message is the same of the next message
-  bool isNextUser;
+  bool? isNextUser;
 
   /// The message
   Message message;
@@ -61,11 +61,11 @@ class MessageDetails {
     List<Message> messages,
     this.index,
   ) {
-    isMyMessage = message.user.id == StreamChat.of(context).user.id;
+    isMyMessage = message.user?.id == StreamChat.of(context).user?.id;
     isLastUser = index + 1 < messages.length &&
-        message.user.id == messages[index + 1]?.user?.id;
+        message.user?.id == messages[index + 1].user?.id;
     isNextUser =
-        index - 1 >= 0 && message.user.id == messages[index - 1]?.user?.id;
+        index - 1 >= 0 && message.user!.id == messages[index - 1].user?.id;
   }
 }
 
@@ -112,7 +112,7 @@ class MessageDetails {
 class MessageListView extends StatefulWidget {
   /// Instantiate a new MessageListView
   MessageListView({
-    Key key,
+    Key? key,
     this.showScrollToBottom = true,
     this.messageBuilder,
     this.parentMessageBuilder,
@@ -145,52 +145,52 @@ class MessageListView extends StatefulWidget {
   }) : super(key: key);
 
   /// Function used to build a custom message widget
-  final MessageBuilder messageBuilder;
+  final MessageBuilder? messageBuilder;
 
   /// Function used to build a custom system message widget
-  final SystemMessageBuilder systemMessageBuilder;
+  final SystemMessageBuilder? systemMessageBuilder;
 
   /// Function used to build a custom parent message widget
-  final ParentMessageBuilder parentMessageBuilder;
+  final ParentMessageBuilder? parentMessageBuilder;
 
   /// Function used to build a custom thread widget
-  final ThreadBuilder threadBuilder;
+  final ThreadBuilder? threadBuilder;
 
   /// Function called when tapping on a thread
   /// By default it calls [Navigator.push] using the widget built using [threadBuilder]
-  final ThreadTapCallback onThreadTap;
+  final ThreadTapCallback? onThreadTap;
 
   /// If true will show a scroll to bottom message when there are new messages and the scroll offset is not zero
   final bool showScrollToBottom;
 
   /// Parent message in case of a thread
-  final Message parentMessage;
+  final Message? parentMessage;
 
   /// Builder used to render date dividers
-  final Widget Function(DateTime) dateDividerBuilder;
+  final Widget Function(DateTime)? dateDividerBuilder;
 
   /// Index of an item to initially align within the viewport.
-  final int initialScrollIndex;
+  final int? initialScrollIndex;
 
   /// Determines where the leading edge of the item at [initialScrollIndex]
   /// should be placed.
-  final double initialAlignment;
+  final double? initialAlignment;
 
   /// Controller for jumping or scrolling to an item.
-  final ItemScrollController scrollController;
+  final ItemScrollController? scrollController;
 
   /// Provides a listenable iterable of [itemPositions] of items that are on
   /// screen and their locations.
-  final ItemPositionsListener itemPositionListener;
+  final ItemPositionsListener? itemPositionListener;
 
   /// The ScrollPhysics used by the ListView
   final ScrollPhysics scrollPhysics;
 
   /// Called when message item gets swiped
-  final OnMessageSwiped onMessageSwiped;
+  final OnMessageSwiped? onMessageSwiped;
 
   ///
-  final ReplyTapCallback onReplyTap;
+  final ReplyTapCallback? onReplyTap;
 
   /// If true the list will highlight the initialMessage if there is any.
   ///
@@ -198,64 +198,64 @@ class MessageListView extends StatefulWidget {
   final bool highlightInitialMessage;
 
   /// Color used while highlighting initial message
-  final Color messageHighlightColor;
+  final Color? messageHighlightColor;
 
-  final ShowMessageCallback onShowMessage;
+  final ShowMessageCallback? onShowMessage;
 
   final bool showConnectionStateTile;
 
   /// Function called when messages are fetched
-  final Widget Function(BuildContext, List<Message>) messageListBuilder;
+  final Widget Function(BuildContext, List<Message>)? messageListBuilder;
 
   /// Function used to build a loading widget
-  final WidgetBuilder loadingBuilder;
+  final WidgetBuilder? loadingBuilder;
 
   /// Function used to build an empty widget
-  final WidgetBuilder emptyBuilder;
+  final WidgetBuilder? emptyBuilder;
 
   /// Callback triggered when an error occurs while performing the given request.
   /// This parameter can be used to display an error message to users in the event
   /// of a connection failure.
-  final ErrorBuilder errorWidgetBuilder;
+  final ErrorBuilder? errorWidgetBuilder;
 
   /// Predicate used to filter messages
-  final bool Function(Message) messageFilter;
+  final bool Function(Message)? messageFilter;
 
   /// Attachment builders for the default message widget
   /// Please change this in the [MessageWidget] if you are using a custom implementation
-  final Map<String, AttachmentBuilder> customAttachmentBuilders;
+  final Map<String, AttachmentBuilder>? customAttachmentBuilders;
 
   /// Called when any message is tapped except a system message (use [onSystemMessageTap] instead)
-  final OnMessageTap onMessageTap;
+  final OnMessageTap? onMessageTap;
 
   /// Called when system message is tapped
-  final OnMessageTap onSystemMessageTap;
+  final OnMessageTap? onSystemMessageTap;
 
   /// Customize onTap on attachment
-  final void Function(Message message, Attachment attachment) onAttachmentTap;
+  final void Function(Message message, Attachment attachment)? onAttachmentTap;
 
   /// Customize the MessageWidget textBuilder
-  final void Function(BuildContext context, Message message) textBuilder;
+  final void Function(BuildContext context, Message message)? textBuilder;
 
   @override
   _MessageListViewState createState() => _MessageListViewState();
 }
 
 class _MessageListViewState extends State<MessageListView> {
-  ItemScrollController _scrollController;
+  ItemScrollController? _scrollController;
-  Function _onThreadTap;
+  Function? _onThreadTap;
   bool _showScrollToBottom = false;
-  ItemPositionsListener _itemPositionListener;
+  late final ItemPositionsListener _itemPositionListener;
-  int _messageListLength;
+  int? _messageListLength;
-  StreamChannelState streamChannel;
+  StreamChannelState? streamChannel;
 
-  int get _initialIndex {
+  int? get _initialIndex {
     if (widget.initialScrollIndex != null) return widget.initialScrollIndex;
-    if (streamChannel.initialMessageId != null) {
+    if (streamChannel!.initialMessageId != null) {
-      final messages = streamChannel.channel.state.messages;
+      final messages = streamChannel!.channel.state!.messages;
       final totalMessages = messages.length;
       final messageIndex = messages.indexWhere((e) {
-        return e.id == streamChannel.initialMessageId;
+        return e.id == streamChannel!.initialMessageId;
       });
       final index = totalMessages - messageIndex;
       if (index != 0) return index - 1;
@@ -264,24 +264,24 @@ class _MessageListViewState extends State<MessageListView> {
     return 0;
   }
 
-  double get _initialAlignment {
+  double? get _initialAlignment {
     if (widget.initialAlignment != null) return widget.initialAlignment;
     return 0;
   }
 
   bool _isInitialMessage(String id) {
-    return streamChannel.initialMessageId == id;
+    return streamChannel!.initialMessageId == id;
   }
 
-  bool get _upToDate => streamChannel.channel.state.isUpToDate;
+  bool get _upToDate => streamChannel!.channel.state!.isUpToDate;
 
   bool get _isThreadConversation => widget.parentMessage != null;
 
   bool _topPaginationActive = false;
   bool _bottomPaginationActive = false;
 
-  int initialIndex;
+  int? initialIndex;
-  double initialAlignment;
+  double? initialAlignment;
 
   List<Message> messages = <Message>[];
 
@@ -343,9 +343,9 @@ class _MessageListViewState extends State<MessageListView> {
 
     if (_messageListLength != null) {
       if (_bottomPaginationActive || (_inBetweenList && _upToDate)) {
-        if (_itemPositionListener.itemPositions.value?.isNotEmpty == true) {
+        if (_itemPositionListener.itemPositions.value.isNotEmpty == true) {
           final first = _itemPositionListener.itemPositions.value.first;
-          final diff = newMessagesListLength - _messageListLength;
+          final diff = newMessagesListLength - _messageListLength!;
           if (diff > 0) {
             initialIndex = first.index + diff;
             initialAlignment = first.itemLeadingEdge;
@@ -413,7 +413,7 @@ class _MessageListViewState extends State<MessageListView> {
                   _inBetweenList = true;
                 },
                 child: ScrollablePositionedList.separated(
-                  key: ValueKey(initialIndex + initialAlignment),
+                  key: ValueKey(initialIndex! + initialAlignment!),
                   itemPositionsListener: _itemPositionListener,
                   addAutomaticKeepAlives: true,
                   initialScrollIndex: initialIndex ?? 0,
@@ -427,7 +427,7 @@ class _MessageListViewState extends State<MessageListView> {
                     if (i == messages.length) return Offstage();
                     if (i == 0) return SizedBox(height: 30);
                     if (i == messages.length + 1) {
-                      final replyCount = widget.parentMessage.replyCount;
+                      final replyCount = widget.parentMessage!.replyCount;
                       return Container(
                         decoration: BoxDecoration(
                           gradient:
@@ -454,7 +454,7 @@ class _MessageListViewState extends State<MessageListView> {
                       Units.DAY,
                     )) {
                       final divider = widget.dateDividerBuilder != null
-                          ? widget.dateDividerBuilder(
+                          ? widget.dateDividerBuilder!(
                               nextMessage.createdAt.toLocal(),
                             )
                           : DateDivider(
@@ -472,8 +472,8 @@ class _MessageListViewState extends State<MessageListView> {
                     );
 
                     final isNextUserSame =
-                        message.user.id == nextMessage.user?.id;
+                        message.user!.id == nextMessage.user?.id;
-                    final isThread = message.replyCount > 0;
+                    final isThread = message.replyCount! > 0;
                     final isDeleted = message.isDeleted;
                     if (timeDiff >= 1 ||
                         !isNextUserSame ||
@@ -486,12 +486,12 @@ class _MessageListViewState extends State<MessageListView> {
                   itemBuilder: (context, i) {
                     if (i == messages.length + 2) {
                       if (widget.parentMessageBuilder != null) {
-                        return widget.parentMessageBuilder(
+                        return widget.parentMessageBuilder!(
                           context,
                           widget.parentMessage,
                         );
                       } else {
-                        return buildParentMessage(widget.parentMessage);
+                        return buildParentMessage(widget.parentMessage!);
                       }
                     }
                     if (i == messages.length + 1) {
@@ -528,7 +528,7 @@ class _MessageListViewState extends State<MessageListView> {
                       if (widget.messageBuilder != null) {
                         messageWidget = Builder(
                           key: ValueKey<String>('MESSAGE-${message.id}'),
-                          builder: (context) => widget.messageBuilder(
+                          builder: (context) => widget.messageBuilder!(
                               context,
                               MessageDetails(
                                 context,
@@ -555,7 +555,7 @@ class _MessageListViewState extends State<MessageListView> {
           child: ValueListenableBuilder<Iterable<ItemPosition>>(
             valueListenable: _itemPositionListener.itemPositions,
             builder: (context, values, _) {
-              final items = _itemPositionListener.itemPositions?.value;
+              final items = _itemPositionListener.itemPositions.value;
               if (items.isEmpty || messages.isEmpty) {
                 return SizedBox();
               }
@@ -571,7 +571,7 @@ class _MessageListViewState extends State<MessageListView> {
               }
 
               return widget.dateDividerBuilder != null
-                  ? widget.dateDividerBuilder(
+                  ? widget.dateDividerBuilder!(
                       messages[index].createdAt.toLocal(),
                     )
                   : DateDivider(
@@ -585,8 +585,8 @@ class _MessageListViewState extends State<MessageListView> {
   }
 
   Future<void> _paginateData(
-      StreamChannelState channel, QueryDirection direction) {
+      StreamChannelState? channel, QueryDirection direction) {
-    return _messageListController.paginateData(direction: direction);
+    return _messageListController.paginateData!(direction: direction);
   }
 
   ItemPosition _getTopElement(Iterable<ItemPosition> values) {
@@ -599,8 +599,8 @@ class _MessageListViewState extends State<MessageListView> {
   Widget _buildScrollToBottom() {
     return StreamBuilder<Tuple2<bool, int>>(
       stream: Rx.combineLatest2(
-        streamChannel.channel.state.isUpToDateStream,
+        streamChannel!.channel.state!.isUpToDateStream,
-        streamChannel.channel.state.unreadCountStream,
+        streamChannel!.channel.state!.unreadCountStream,
         (bool isUpToDate, int unreadCount) => Tuple2(isUpToDate, unreadCount),
       ),
       builder: (_, snapshot) {
@@ -609,15 +609,15 @@ class _MessageListViewState extends State<MessageListView> {
         } else if (!snapshot.hasData) {
           return Offstage();
         }
-        final isUpToDate = snapshot.data.item1;
+        final isUpToDate = snapshot.data!.item1;
         final showScrollToBottom = !isUpToDate || _showScrollToBottom;
         if (!showScrollToBottom) {
           return Offstage();
         }
-        final unreadCount = snapshot.data.item2;
+        final unreadCount = snapshot.data!.item2;
         final showUnreadCount = unreadCount > 0 &&
-            streamChannel.channel.state.members.any(
+            streamChannel!.channel.state!.members.any((e) =>
-                (e) => e.userId == streamChannel.channel.client.state.user.id);
+                e.userId == streamChannel!.channel.client.state.user!.id);
         return Positioned(
           bottom: 8,
           right: 8,
@@ -630,15 +630,15 @@ class _MessageListViewState extends State<MessageListView> {
                 backgroundColor: StreamChatTheme.of(context).colorTheme.white,
                 onPressed: () {
                   if (unreadCount > 0) {
-                    streamChannel.channel.markRead();
+                    streamChannel!.channel.markRead();
                   }
                   if (!_upToDate) {
                     _bottomPaginationActive = false;
                     _topPaginationActive = false;
-                    streamChannel.reloadChannel();
+                    streamChannel!.reloadChannel();
                   } else {
                     setState(() => _showScrollToBottom = false);
-                    _scrollController.scrollTo(
+                    _scrollController!.scrollTo(
                       index: 0,
                       duration: Duration(seconds: 1),
                       curve: Curves.easeInOut,
@@ -676,12 +676,12 @@ class _MessageListViewState extends State<MessageListView> {
   }
 
   Widget _buildLoadingIndicator(
-    StreamChannelState streamChannel,
+    StreamChannelState? streamChannel,
     QueryDirection direction,
   ) {
     final stream = direction == QueryDirection.top
-        ? streamChannel.queryTopMessages
+        ? streamChannel!.queryTopMessages
-        : streamChannel.queryBottomMessages;
+        : streamChannel!.queryBottomMessages;
     return StreamBuilder<bool>(
       key: Key('LOADING-INDICATOR'),
       stream: stream,
@@ -698,7 +698,7 @@ class _MessageListViewState extends State<MessageListView> {
             ),
           );
         }
-        if (!snapshot.data) {
+        if (!snapshot.data!) {
           if (!_isThreadConversation && direction == QueryDirection.top) {
             return Container(
               height: 52,
@@ -721,13 +721,13 @@ class _MessageListViewState extends State<MessageListView> {
     BuildContext context,
     Message message,
     List<Message> messages,
-    StreamChannelState streamChannel,
+    StreamChannelState? streamChannel,
   ) {
     Widget messageWidget;
     if (widget.messageBuilder != null) {
       messageWidget = Builder(
         key: ValueKey<String>('TOP-MESSAGE'),
-        builder: (_) => widget.messageBuilder(
+        builder: (_) => widget.messageBuilder!(
           context,
           MessageDetails(
             context,
@@ -748,13 +748,13 @@ class _MessageListViewState extends State<MessageListView> {
     BuildContext context,
     Message message,
     List<Message> messages,
-    StreamChannelState streamChannel,
+    StreamChannelState? streamChannel,
   ) {
     Widget messageWidget;
     if (widget.messageBuilder != null) {
       messageWidget = Builder(
         key: ValueKey<String>('BOTTOM-MESSAGE-${message.id}'),
-        builder: (_) => widget.messageBuilder(
+        builder: (_) => widget.messageBuilder!(
           context,
           MessageDetails(
             context,
@@ -774,10 +774,10 @@ class _MessageListViewState extends State<MessageListView> {
       onVisibilityChanged: (visibility) {
         final isVisible = visibility.visibleBounds != Rect.zero;
         if (isVisible) {
-          final channel = streamChannel.channel;
+          final channel = streamChannel!.channel;
           if (_upToDate &&
               channel.config?.readEvents == true &&
-              channel.state.unreadCount > 0) {
+              channel.state!.unreadCount! > 0) {
             streamChannel.channel.markRead();
           }
         }
@@ -792,8 +792,8 @@ class _MessageListViewState extends State<MessageListView> {
   Widget buildParentMessage(
     Message message,
   ) {
-    final isMyMessage = message.user.id == StreamChat.of(context).user.id;
+    final isMyMessage = message.user!.id == StreamChat.of(context).user!.id;
-    final isOnlyEmoji = message.text.isOnlyEmoji;
+    final isOnlyEmoji = message.text!.isOnlyEmoji;
 
     return MessageWidget(
       showThreadReplyIndicator: false,
@@ -809,7 +809,7 @@ class _MessageListViewState extends State<MessageListView> {
       showUsername: !isMyMessage,
       padding: const EdgeInsets.all(8.0),
       showSendingIndicator: false,
-      onThreadTap: _onThreadTap,
+      onThreadTap: _onThreadTap as void Function(Message)?,
       borderRadiusGeometry: BorderRadius.only(
         topLeft: Radius.circular(16),
         bottomLeft: Radius.circular(2),
@@ -832,18 +832,19 @@ class _MessageListViewState extends State<MessageListView> {
             break;
           case ReturnActionType.reply:
             FocusScope.of(context).unfocus();
-            widget.onMessageSwiped(message);
+            widget.onMessageSwiped!(message);
             break;
         }
       },
       customAttachmentBuilders: widget.customAttachmentBuilders,
       onMessageTap: (message) {
         if (widget.onMessageTap != null) {
-          widget.onMessageTap(message);
+          widget.onMessageTap!(message);
         }
         FocusScope.of(context).unfocus();
       },
-      textBuilder: widget.textBuilder,
+      textBuilder:
+          widget.textBuilder as Widget Function(BuildContext, Message)?,
     );
   }
 
@@ -860,18 +861,18 @@ class _MessageListViewState extends State<MessageListView> {
             message: message,
             onMessageTap: (message) {
               if (widget.onSystemMessageTap != null) {
-                widget.onSystemMessageTap(message);
+                widget.onSystemMessageTap!(message);
               }
               FocusScope.of(context).unfocus();
             },
           );
     }
 
-    final userId = StreamChat.of(context).user.id;
+    final userId = StreamChat.of(context).user!.id;
-    final isMyMessage = message.user.id == userId;
+    final isMyMessage = message.user!.id == userId;
     final nextMessage = index - 2 >= 0 ? messages[index - 2] : null;
     final isNextUserSame =
-        nextMessage != null && message.user.id == nextMessage.user.id;
+        nextMessage != null && message.user!.id == nextMessage.user!.id;
 
     num timeDiff = 0;
     if (nextMessage != null) {
@@ -881,27 +882,26 @@ class _MessageListViewState extends State<MessageListView> {
       );
     }
 
-    final channel = streamChannel.channel;
+    final channel = streamChannel!.channel;
     final readList = channel.state?.read?.where((read) {
           if (read.user.id == userId) return false;
           return (read.lastRead.isAfter(message.createdAt) ||
               read.lastRead.isAtSameMomentAs(message.createdAt));
-        })?.toList() ??
+        }).toList() ??
         [];
 
     final allRead = readList.length >= (channel.memberCount ?? 0) - 1;
     final hasFileAttachment =
-        message.attachments?.any((it) => it.type == 'file') == true;
+        message.attachments.any((it) => it.type == 'file') == true;
 
     final isThreadMessage =
-        message?.parentId != null && message?.showInChannel == true;
+        message.parentId != null && message.showInChannel == true;
 
-    final hasReplies = message.replyCount > 0;
+    final hasReplies = message.replyCount! > 0;
 
     final attachmentBorderRadius = hasFileAttachment ? 12.0 : 14.0;
 
-    final showTimeStamp = message.createdAt != null &&
+    final showTimeStamp = (!isThreadMessage || _isThreadConversation) &&
-        (!isThreadMessage || _isThreadConversation) &&
         !hasReplies &&
         (timeDiff >= 1 || !isNextUserSame);
 
@@ -921,10 +921,10 @@ class _MessageListViewState extends State<MessageListView> {
 
     final showInChannelIndicator = !_isThreadConversation && isThreadMessage;
     final showThreadReplyIndicator = !_isThreadConversation && hasReplies;
-    final isOnlyEmoji = message.text.isOnlyEmoji;
+    final isOnlyEmoji = message.text!.isOnlyEmoji;
 
     final hasUrlAttachment =
-        message.attachments?.any((it) => it.ogScrapeUrl != null) == true;
+        message.attachments.any((it) => it.ogScrapeUrl != null) == true;
 
     final borderSide =
         isOnlyEmoji || hasUrlAttachment || (isMyMessage && !hasFileAttachment)
@@ -954,8 +954,8 @@ class _MessageListViewState extends State<MessageListView> {
         if (messages.map((e) => e.id).contains(quotedMessageId)) {
           scrollToIndex();
         } else {
-          await streamChannel.loadChannelAtMessage(quotedMessageId).then((_) {
+          await streamChannel!.loadChannelAtMessage(quotedMessageId).then((_) {
-            WidgetsBinding.instance.addPostFrameCallback((_) {
+            WidgetsBinding.instance!.addPostFrameCallback((_) {
               if (messages.map((e) => e.id).contains(quotedMessageId)) {
                 scrollToIndex();
               }
@@ -968,7 +968,7 @@ class _MessageListViewState extends State<MessageListView> {
       showThreadReplyMessage: !isThreadMessage,
       showFlagButton: !isMyMessage,
       borderSide: borderSide,
-      onThreadTap: _onThreadTap,
+      onThreadTap: _onThreadTap as void Function(Message)?,
       onReplyTap: widget.onReplyTap,
       attachmentBorderRadiusGeometry: BorderRadius.only(
         topLeft: Radius.circular(attachmentBorderRadius),
@@ -1008,19 +1008,20 @@ class _MessageListViewState extends State<MessageListView> {
             break;
           case ReturnActionType.reply:
             FocusScope.of(context).unfocus();
-            widget.onMessageSwiped(message);
+            widget.onMessageSwiped!(message);
             break;
         }
       },
       customAttachmentBuilders: widget.customAttachmentBuilders,
       onMessageTap: (message) {
         if (widget.onMessageTap != null) {
-          widget.onMessageTap(message);
+          widget.onMessageTap!(message);
         }
         FocusScope.of(context).unfocus();
       },
       onAttachmentTap: widget.onAttachmentTap,
-      textBuilder: widget.textBuilder,
+      textBuilder:
+          widget.textBuilder as Widget Function(BuildContext, Message)?,
     );
 
     if (!message.isDeleted &&
@@ -1033,7 +1034,7 @@ class _MessageListViewState extends State<MessageListView> {
         child: Swipeable(
           onSwipeEnd: () {
             FocusScope.of(context).unfocus();
-            widget.onMessageSwiped(message);
+            widget.onMessageSwiped!(message);
           },
           backgroundIcon: StreamSvgIcon.reply(
             color: StreamChatTheme.of(context).colorTheme.accentBlue,
@@ -1049,7 +1050,7 @@ class _MessageListViewState extends State<MessageListView> {
       final colorTheme = StreamChatTheme.of(context).colorTheme;
       final highlightColor =
           widget.messageHighlightColor ?? colorTheme.highlight;
-      child = TweenAnimationBuilder<Color>(
+      child = TweenAnimationBuilder<Color?>(
         tween: ColorTween(
           begin: highlightColor,
           end: colorTheme.white.withOpacity(0),
@@ -1071,7 +1072,7 @@ class _MessageListViewState extends State<MessageListView> {
     return child;
   }
 
-  StreamSubscription _messageNewListener;
+  StreamSubscription? _messageNewListener;
 
   @override
   void initState() {
@@ -1085,13 +1086,14 @@ class _MessageListViewState extends State<MessageListView> {
     initialAlignment = _initialAlignment;
 
     _messageNewListener =
-        streamChannel.channel.on(EventType.messageNew).listen((event) {
+        streamChannel!.channel.on(EventType.messageNew).listen((event) {
       if (_upToDate) {
         _bottomPaginationActive = false;
         _topPaginationActive = false;
       }
-      if (event.message.user.id == streamChannel.channel.client.state.user.id) {
+      if (event.message!.user!.id ==
-        WidgetsBinding.instance.addPostFrameCallback((_) {
+          streamChannel!.channel.client.state.user!.id) {
+        WidgetsBinding.instance!.addPostFrameCallback((_) {
           _scrollController?.jumpTo(
             index: 0,
           );
@@ -1100,7 +1102,7 @@ class _MessageListViewState extends State<MessageListView> {
     });
 
     if (_isThreadConversation) {
-      streamChannel.getReplies(widget.parentMessage.id);
+      streamChannel!.getReplies(widget.parentMessage!.id);
     }
 
     _getOnThreadTap();
@@ -1110,10 +1112,10 @@ class _MessageListViewState extends State<MessageListView> {
   void _getOnThreadTap() {
     if (widget.onThreadTap != null) {
       _onThreadTap = (Message message) {
-        widget.onThreadTap(
+        widget.onThreadTap!(
             message,
             widget.threadBuilder != null
-                ? widget.threadBuilder(context, message)
+                ? widget.threadBuilder!(context, message)
                 : null);
       };
     } else if (widget.threadBuilder != null) {
@@ -1122,14 +1124,14 @@ class _MessageListViewState extends State<MessageListView> {
           context,
           MaterialPageRoute(builder: (_) {
             return StreamBuilder<Message>(
-                stream: streamChannel.channel.state.messagesStream.map(
+                stream: streamChannel!.channel.state!.messagesStream.map(
                     (messages) =>
-                        messages.firstWhere((m) => m.id == message.id)),
+                        messages!.firstWhere((m) => m.id == message.id)),
                 initialData: message,
                 builder: (_, snapshot) {
                   return StreamChannel(
-                    channel: streamChannel.channel,
+                    channel: streamChannel!.channel,
-                    child: widget.threadBuilder(context, snapshot.data),
+                    child: widget.threadBuilder!(context, snapshot.data),
                   );
                 });
           }),
@@ -1141,7 +1143,7 @@ class _MessageListViewState extends State<MessageListView> {
   @override
   void dispose() {
     if (!_upToDate) {
-      streamChannel.reloadChannel();
+      streamChannel!.reloadChannel();
     }
     _messageNewListener?.cancel();
     super.dispose();

packages/stream_chat_flutter/lib/src/message_reactions_modal.dart

@@ -14,19 +14,19 @@ import 'stream_chat_theme.dart';
 
 class MessageReactionsModal extends StatelessWidget {
   final Message message;
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
   final bool reverse;
   final bool showReactions;
   final DisplayWidget showUserAvatar;
-  final ShapeBorder messageShape;
+  final ShapeBorder? messageShape;
-  final ShapeBorder attachmentShape;
+  final ShapeBorder? attachmentShape;
-  final void Function(User) onUserAvatarTap;
+  final void Function(User)? onUserAvatarTap;
-  final BorderRadius attachmentBorderRadiusGeometry;
+  final BorderRadius? attachmentBorderRadiusGeometry;
 
   const MessageReactionsModal({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.showReactions = true,
     this.messageShape,
     this.attachmentShape,
@@ -42,10 +42,10 @@ class MessageReactionsModal extends StatelessWidget {
     final user = StreamChat.of(context).user;
 
     final roughMaxSize = 2 * size.width / 3;
-    var messageTextLength = message.text.length;
+    var messageTextLength = message.text!.length;
     if (message.quotedMessage != null) {
-      var quotedMessageLength = message.quotedMessage.text.length + 40;
+      var quotedMessageLength = message.quotedMessage!.text!.length + 40;
-      if (message.quotedMessage.attachments?.isNotEmpty == true) {
+      if (message.quotedMessage!.attachments.isNotEmpty == true) {
         quotedMessageLength += 40;
       }
       if (quotedMessageLength > messageTextLength) {
@@ -53,8 +53,8 @@ class MessageReactionsModal extends StatelessWidget {
       }
     }
     final roughSentenceSize =
-        messageTextLength * messageTheme.messageText.fontSize * 1.2;
+        messageTextLength * (messageTheme?.messageText?.fontSize ?? 1) * 1.2;
-    final divFactor = message.attachments?.isNotEmpty == true
+    final divFactor = message.attachments.isNotEmpty == true
         ? 1
         : (roughSentenceSize == 0 ? 1 : (roughSentenceSize / roughMaxSize));
 
@@ -64,7 +64,7 @@ class MessageReactionsModal extends StatelessWidget {
       curve: Curves.easeInOutBack,
       builder: (context, val, snapshot) {
         final hasFileAttachment =
-            message.attachments?.any((it) => it.type == 'file') == true;
+            message.attachments.any((it) => it.type == 'file') == true;
         return GestureDetector(
           behavior: HitTestBehavior.translucent,
           onTap: () => Navigator.maybePop(context),
@@ -92,11 +92,10 @@ class MessageReactionsModal extends StatelessWidget {
                         crossAxisAlignment: CrossAxisAlignment.stretch,
                         children: <Widget>[
                           if (showReactions &&
-                              (message.status == MessageSendingStatus.sent ||
+                              (message.status == MessageSendingStatus.sent))
-                                  message.status == null))
                             Align(
                               alignment: Alignment(
-                                  user.id == message.user.id
+                                  user!.id == message.user!.id
                                       ? (divFactor > 1.0
                                           ? 0.0
                                           : (1.0 - divFactor))
@@ -115,8 +114,8 @@ class MessageReactionsModal extends StatelessWidget {
                               key: Key('MessageWidget'),
                               reverse: reverse,
                               message: message.copyWith(
-                                text: message.text.length > 200
+                                text: message.text!.length > 200
-                                    ? '${message.text.substring(0, 200)}...'
+                                    ? '${message.text!.substring(0, 200)}...'
                                     : message.text,
                               ),
                               messageTheme: messageTheme,
@@ -138,12 +137,11 @@ class MessageReactionsModal extends StatelessWidget {
                               showInChannelIndicator: false,
                               textPadding: EdgeInsets.symmetric(
                                 vertical: 8.0,
-                                horizontal: message.text.isOnlyEmoji ? 0 : 16.0,
+                                horizontal:
+                                    message.text!.isOnlyEmoji ? 0 : 16.0,
                               ),
                               showReactionPickerIndicator: showReactions &&
-                                  (message.status ==
+                                  (message.status == MessageSendingStatus.sent),
-                                          MessageSendingStatus.sent ||
-                                      message.status == null),
                             ),
                           ),
                           if (message.latestReactions?.isNotEmpty == true) ...[
@@ -188,10 +186,10 @@ class MessageReactionsModal extends StatelessWidget {
                   spacing: 16,
                   runSpacing: 16,
                   alignment: WrapAlignment.start,
-                  children: message.latestReactions
+                  children: message.latestReactions!
                       .map((e) => _buildReaction(
                             e,
-                            currentUser,
+                            currentUser!,
                             context,
                           ))
                       .toList(),
@@ -209,7 +207,7 @@ class MessageReactionsModal extends StatelessWidget {
     User currentUser,
     BuildContext context,
   ) {
-    final isCurrentUser = reaction.user.id == currentUser.id;
+    final isCurrentUser = reaction.user?.id == currentUser.id;
     return ConstrainedBox(
       constraints: BoxConstraints.loose(Size(
         64,
@@ -225,7 +223,7 @@ class MessageReactionsModal extends StatelessWidget {
             children: [
               UserAvatar(
                 onTap: onUserAvatarTap,
-                user: reaction.user,
+                user: reaction.user!,
                 constraints: BoxConstraints.tightFor(
                   height: 64,
                   width: 64,
@@ -246,8 +244,10 @@ class MessageReactionsModal extends StatelessWidget {
                   child: ReactionBubble(
                     reactions: [reaction],
                     flipTail: !reverse,
-                    borderColor: messageTheme.reactionsBorderColor,
+                    borderColor: messageTheme?.reactionsBorderColor ??
-                    backgroundColor: messageTheme.reactionsBackgroundColor,
+                        Colors.transparent,
+                    backgroundColor: messageTheme?.reactionsBackgroundColor ??
+                        Colors.transparent,
                     maskColor: StreamChatTheme.of(context).colorTheme.white,
                     tailCirclesSpacing: 1,
                     highlightOwnReactions: false,
@@ -258,7 +258,7 @@ class MessageReactionsModal extends StatelessWidget {
           ),
           const SizedBox(height: 8),
           Text(
-            reaction.user.name.split(' ')[0],
+            reaction.user!.name.split(' ')[0],
             style: StreamChatTheme.of(context).textTheme.footnoteBold,
             textAlign: TextAlign.center,
           ),

packages/stream_chat_flutter/lib/src/message_search_item.dart

@@ -12,8 +12,8 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 class MessageSearchItem extends StatelessWidget {
   /// Instantiate a new MessageSearchItem
   const MessageSearchItem({
-    Key key,
+    Key? key,
-    @required this.getMessageResponse,
+    required this.getMessageResponse,
     this.onTap,
     this.showOnlineStatus = true,
   }) : super(key: key);
@@ -22,7 +22,7 @@ class MessageSearchItem extends StatelessWidget {
   final GetMessageResponse getMessageResponse;
 
   /// Function called when tapping this widget
-  final VoidCallback onTap;
+  final VoidCallback? onTap;
 
   /// If true the [MessageSearchItem] will show the current online Status
   final bool showOnlineStatus;
@@ -31,8 +31,8 @@ class MessageSearchItem extends StatelessWidget {
   Widget build(BuildContext context) {
     final message = getMessageResponse.message;
     final channel = getMessageResponse.channel;
-    final channelName = channel.extraData['name'];
+    final channelName = channel?.extraData['name'];
-    final user = message.user;
+    final user = message.user!;
     return ListTile(
       onTap: onTap,
       leading: UserAvatar(
@@ -46,7 +46,7 @@ class MessageSearchItem extends StatelessWidget {
       title: Row(
         children: [
           Text(
-            user.id == StreamChat.of(context).user.id ? 'You' : user.name,
+            user.id == StreamChat.of(context).user?.id ? 'You' : user.name,
             style: StreamChatTheme.of(context).channelPreviewTheme.title,
           ),
           if (channelName != null) ...[
@@ -55,12 +55,12 @@ class MessageSearchItem extends StatelessWidget {
               style: StreamChatTheme.of(context)
                   .channelPreviewTheme
                   .title
-                  .copyWith(
+                  ?.copyWith(
                     fontWeight: FontWeight.normal,
                   ),
             ),
             Text(
-              channelName,
+              channelName as String,
               style: StreamChatTheme.of(context).channelPreviewTheme.title,
             ),
           ],
@@ -96,14 +96,10 @@ class MessageSearchItem extends StatelessWidget {
   }
 
   Widget _buildSubtitle(BuildContext context, Message message) {
-    if (message == null) {
-      return SizedBox();
-    }
-
     var text = message.text;
     if (message.isDeleted) {
       text = 'This message was deleted.';
-    } else if (message.attachments != null) {
+    } else if (message.attachments.isNotEmpty) {
       final parts = <String>[
         ...message.attachments.map((e) {
           if (e.type == 'image') {
@@ -116,7 +112,7 @@ class MessageSearchItem extends StatelessWidget {
           return e == message.attachments.last
               ? (e.title ?? 'File')
               : '${e.title ?? 'File'} , ';
-        }).where((e) => e != null),
+        }),
         message.text ?? '',
       ];
 
@@ -125,15 +121,15 @@ class MessageSearchItem extends StatelessWidget {
 
     return Text.rich(
       _getDisplayText(
-        text,
+        text!,
         message.mentionedUsers,
         message.attachments,
-        StreamChatTheme.of(context).channelPreviewTheme.subtitle.copyWith(
+        StreamChatTheme.of(context).channelPreviewTheme.subtitle?.copyWith(
               fontStyle: (message.isSystem || message.isDeleted)
                   ? FontStyle.italic
                   : FontStyle.normal,
             ),
-        StreamChatTheme.of(context).channelPreviewTheme.subtitle.copyWith(
+        StreamChatTheme.of(context).channelPreviewTheme.subtitle?.copyWith(
               fontStyle: (message.isSystem || message.isDeleted)
                   ? FontStyle.italic
                   : FontStyle.normal,
@@ -149,26 +145,24 @@ class MessageSearchItem extends StatelessWidget {
       String text,
       List<User> mentions,
       List<Attachment> attachments,
-      TextStyle normalTextStyle,
+      TextStyle? normalTextStyle,
-      TextStyle mentionsTextStyle) {
+      TextStyle? mentionsTextStyle) {
     var textList = text.split(' ');
     var resList = <TextSpan>[];
     for (var e in textList) {
-      if (mentions != null &&
+      if (mentions.isNotEmpty &&
-          mentions.isNotEmpty &&
           mentions.any((element) => '@${element.name}' == e)) {
         resList.add(TextSpan(
           text: '$e ',
           style: mentionsTextStyle,
         ));
-      } else if (attachments != null &&
+      } else if (attachments.isNotEmpty &&
-          attachments.isNotEmpty &&
           attachments
               .where((e) => e.title != null)
               .any((element) => element.title == e)) {
         resList.add(TextSpan(
           text: '$e ',
-          style: normalTextStyle.copyWith(fontStyle: FontStyle.italic),
+          style: normalTextStyle?.copyWith(fontStyle: FontStyle.italic),
         ));
       } else {
         resList.add(TextSpan(

packages/stream_chat_flutter/lib/src/message_search_list_view.dart

@@ -10,11 +10,15 @@ typedef MessageSearchItemTapCallback = void Function(GetMessageResponse);
 
 /// Builder used to create a custom [ListUserItem] from a [User]
 typedef MessageSearchItemBuilder = Widget Function(
-    BuildContext, GetMessageResponse);
+  BuildContext,
+  GetMessageResponse,
+);
 
 /// Builder used when [MessageSearchListView] is empty
 typedef EmptyMessageSearchBuilder = Widget Function(
-    BuildContext context, String searchQuery);
+  BuildContext context,
+  String searchQuery,
+);
 
 ///
 /// It shows the list of searched messages.
@@ -47,9 +51,9 @@ typedef EmptyMessageSearchBuilder = Widget Function(
 class MessageSearchListView extends StatefulWidget {
   /// Instantiate a new MessageSearchListView
   const MessageSearchListView({
-    Key key,
+    Key? key,
+    required this.filters,
     this.messageQuery,
-    this.filters,
     this.sortOptions,
     this.paginationParams,
     this.messageFilters,
@@ -66,7 +70,7 @@ class MessageSearchListView extends StatefulWidget {
   }) : super(key: key);
 
   /// Message String to search on
-  final String messageQuery;
+  final String? messageQuery;
 
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
@@ -77,27 +81,27 @@ class MessageSearchListView extends StatefulWidget {
   /// Sorting is based on field and direction, multiple sorting options can be provided.
   /// You can sort based on last_updated, last_message_at, updated_at, created_at or member_count.
   /// Direction can be ascending or descending.
-  final List<SortOption> sortOptions;
+  final List<SortOption>? sortOptions;
 
   /// Pagination parameters
   /// limit: the number of users to return (max is 30)
   /// offset: the offset (max is 1000)
   /// message_limit: how many messages should be included to each channel
-  final PaginationParams paginationParams;
+  final PaginationParams? paginationParams;
 
   /// The message query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Map<String, dynamic> messageFilters;
+  final Map<String, dynamic>? messageFilters;
 
   /// Builder used to create a custom item preview
-  final MessageSearchItemBuilder itemBuilder;
+  final MessageSearchItemBuilder? itemBuilder;
 
   /// Function called when tapping on a [MessageSearchItem]
-  final MessageSearchItemTapCallback onItemTap;
+  final MessageSearchItemTapCallback? onItemTap;
 
   /// Builder used to create a custom item separator
-  final IndexedWidgetBuilder separatorBuilder;
+  final IndexedWidgetBuilder? separatorBuilder;
 
   /// Set it to false to hide total results text
   final bool showResultCount;
@@ -108,16 +112,16 @@ class MessageSearchListView extends StatefulWidget {
   final bool showErrorTile;
 
   /// The builder that is used when the search messages are fetched
-  final Widget Function(List<GetMessageResponse>) childBuilder;
+  final Widget Function(List<GetMessageResponse>)? childBuilder;
 
   /// The builder used when the channel list is empty.
-  final WidgetBuilder emptyBuilder;
+  final WidgetBuilder? emptyBuilder;
 
   /// The builder that will be used in case of error
-  final ErrorBuilder errorBuilder;
+  final ErrorBuilder? errorBuilder;
 
   /// The builder that will be used in case of loading
-  final WidgetBuilder loadingBuilder;
+  final WidgetBuilder? loadingBuilder;
 
   @override
   _MessageSearchListViewState createState() => _MessageSearchListViewState();
@@ -202,11 +206,11 @@ class _MessageSearchListViewState extends State<MessageSearchListView> {
   Widget _listItemBuilder(
       BuildContext context, GetMessageResponse getMessageResponse) {
     if (widget.itemBuilder != null) {
-      return widget.itemBuilder(context, getMessageResponse);
+      return widget.itemBuilder!(context, getMessageResponse);
     }
     return MessageSearchItem(
       getMessageResponse: getMessageResponse,
-      onTap: () => widget.onItemTap(getMessageResponse),
+      onTap: () => widget.onItemTap!(getMessageResponse),
     );
   }
 
@@ -235,7 +239,7 @@ class _MessageSearchListViewState extends State<MessageSearchListView> {
             height: 100,
             padding: EdgeInsets.all(32),
             child: Center(
-              child: snapshot.data ? CircularProgressIndicator() : Container(),
+              child: snapshot.data! ? CircularProgressIndicator() : Container(),
             ),
           );
         });
@@ -249,7 +253,7 @@ class _MessageSearchListViewState extends State<MessageSearchListView> {
       itemCount: items.isNotEmpty ? items.length + 1 : items.length,
       separatorBuilder: (_, index) {
         if (widget.separatorBuilder != null) {
-          return widget.separatorBuilder(context, index);
+          return widget.separatorBuilder!(context, index);
         }
         return _separatorBuilder(context, index);
       },
@@ -262,13 +266,13 @@ class _MessageSearchListViewState extends State<MessageSearchListView> {
     );
     if (widget.pullToRefresh) {
       child = RefreshIndicator(
-        onRefresh: () => _messageSearchListController.loadData(),
+        onRefresh: () => _messageSearchListController.loadData!(),
         child: child,
       );
     }
 
     child = LazyLoadScrollView(
-      onEndOfPage: () => _messageSearchListController.paginateData(),
+      onEndOfPage: () => _messageSearchListController.paginateData!(),
       child: child,
     );
 

packages/stream_chat_flutter/lib/src/message_text.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:flutter/material.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
 import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
@@ -7,43 +8,45 @@ import 'utils.dart';
 
 class MessageText extends StatelessWidget {
   const MessageText({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.onMentionTap,
     this.onLinkTap,
   }) : super(key: key);
 
   final Message message;
-  final void Function(User) onMentionTap;
+  final void Function(User)? onMentionTap;
-  final void Function(String) onLinkTap;
+  final void Function(String)? onLinkTap;
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
 
   @override
   Widget build(BuildContext context) {
-    final text = _replaceMentions(message.text).replaceAll('\n', '\\\n');
+    final text = _replaceMentions(message.text)!.replaceAll('\n', '\\\n');
 
     return MarkdownBody(
       data: text,
       onTapLink: (
         String link,
-        String href,
+        String? href,
         String title,
       ) {
         if (link.startsWith('@')) {
-          final mentionedUser = message.mentionedUsers.firstWhere(
+          final mentionedUser = message.mentionedUsers.firstWhereOrNull(
             (u) => '@${u.name}' == link,
-            orElse: () => null,
           );
+          if (mentionedUser == null) {
+            return;
+          }
 
           if (onMentionTap != null) {
-            onMentionTap(mentionedUser);
+            onMentionTap!(mentionedUser);
           } else {
             print('tap on ${mentionedUser.name}');
           }
         } else {
           if (onLinkTap != null) {
-            onLinkTap(link);
+            onLinkTap!(link);
           } else {
             launchURL(context, link);
           }
@@ -52,23 +55,23 @@ class MessageText extends StatelessWidget {
       styleSheet: MarkdownStyleSheet.fromTheme(
         Theme.of(context).copyWith(
           textTheme: Theme.of(context).textTheme.apply(
-                bodyColor: messageTheme.messageText.color,
+                bodyColor: messageTheme!.messageText!.color,
-                decoration: messageTheme.messageText.decoration,
+                decoration: messageTheme!.messageText!.decoration,
-                decorationColor: messageTheme.messageText.decorationColor,
+                decorationColor: messageTheme!.messageText!.decorationColor,
-                decorationStyle: messageTheme.messageText.decorationStyle,
+                decorationStyle: messageTheme!.messageText!.decorationStyle,
-                fontFamily: messageTheme.messageText.fontFamily,
+                fontFamily: messageTheme!.messageText!.fontFamily,
               ),
         ),
       ).copyWith(
-        a: messageTheme.messageLinks,
+        a: messageTheme!.messageLinks,
-        p: messageTheme.messageText,
+        p: messageTheme!.messageText,
       ),
     );
   }
 
-  String _replaceMentions(String text) {
+  String? _replaceMentions(String? text) {
-    message.mentionedUsers?.map((u) => u.name)?.toSet()?.forEach((userName) {
+    message.mentionedUsers.map((u) => u.name).toSet().forEach((userName) {
-      text = text.replaceAll(
+      text = text!.replaceAll(
           '@$userName', '[@$userName](@${userName.replaceAll(' ', '')})');
     });
     return text;

packages/stream_chat_flutter/lib/src/message_widget.dart

@@ -26,7 +26,7 @@ typedef AttachmentBuilder = Widget Function(
   Message,
   List<Attachment>,
 );
-typedef OnQuotedMessageTap = void Function(String);
+typedef OnQuotedMessageTap = void Function(String?);
 
 /// The display behaviour of a widget
 enum DisplayWidget {
@@ -51,46 +51,46 @@ enum DisplayWidget {
 /// Modify it to change the widget appearance.
 class MessageWidget extends StatefulWidget {
   /// Function called on mention tap
-  final void Function(User) onMentionTap;
+  final void Function(User)? onMentionTap;
 
   /// The function called when tapping on replies
-  final void Function(Message) onThreadTap;
+  final void Function(Message)? onThreadTap;
-  final void Function(Message) onReplyTap;
+  final void Function(Message)? onReplyTap;
-  final Widget Function(BuildContext, Message) editMessageInputBuilder;
+  final Widget Function(BuildContext, Message)? editMessageInputBuilder;
-  final Widget Function(BuildContext, Message) textBuilder;
+  final Widget Function(BuildContext, Message)? textBuilder;
 
   /// Function called on long press
-  final void Function(BuildContext, Message) onMessageActions;
+  final void Function(BuildContext, Message)? onMessageActions;
 
   /// The message
   final Message message;
 
   /// The message theme
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
 
   /// If true the widget will be mirrored
   final bool reverse;
 
   /// The shape of the message text
-  final ShapeBorder shape;
+  final ShapeBorder? shape;
 
   /// The shape of an attachment
-  final ShapeBorder attachmentShape;
+  final ShapeBorder? attachmentShape;
 
   /// The borderside of the message text
-  final BorderSide borderSide;
+  final BorderSide? borderSide;
 
   /// The borderside of an attachment
-  final BorderSide attachmentBorderSide;
+  final BorderSide? attachmentBorderSide;
 
   /// The border radius of the message text
-  final BorderRadiusGeometry borderRadiusGeometry;
+  final BorderRadiusGeometry? borderRadiusGeometry;
 
   /// The border radius of an attachment
-  final BorderRadiusGeometry attachmentBorderRadiusGeometry;
+  final BorderRadiusGeometry? attachmentBorderRadiusGeometry;
 
   /// The padding of the widget
-  final EdgeInsetsGeometry padding;
+  final EdgeInsetsGeometry? padding;
 
   /// The internal padding of the message text
   final EdgeInsetsGeometry textPadding;
@@ -116,18 +116,18 @@ class MessageWidget extends StatefulWidget {
   final bool showInChannelIndicator;
 
   /// The function called when tapping on UserAvatar
-  final void Function(User) onUserAvatarTap;
+  final void Function(User)? onUserAvatarTap;
 
   /// The function called when tapping on a link
-  final void Function(String) onLinkTap;
+  final void Function(String)? onLinkTap;
 
   /// Used in [MessageReactionsModal] and [MessageActionsModal]
   final bool showReactionPickerIndicator;
 
-  final List<Read> readList;
+  final List<Read>? readList;
 
-  final ShowMessageCallback onShowMessage;
+  final ShowMessageCallback? onShowMessage;
-  final ValueChanged<ReturnActionType> onReturnAction;
+  final ValueChanged<ReturnActionType>? onReturnAction;
 
   /// If true show the users username next to the timestamp of the message
   final bool showUsername;
@@ -147,22 +147,22 @@ class MessageWidget extends StatefulWidget {
   final bool translateUserAvatar;
 
   /// Function called when quotedMessage is tapped
-  final OnQuotedMessageTap onQuotedMessageTap;
+  final OnQuotedMessageTap? onQuotedMessageTap;
 
   /// Function called when message is tapped
-  final void Function(Message) onMessageTap;
+  final void Function(Message)? onMessageTap;
 
   /// List of custom actions shown on message long tap
   final List<MessageAction> customActions;
 
   // Customize onTap on attachment
-  final void Function(Message message, Attachment attachment) onAttachmentTap;
+  final void Function(Message message, Attachment attachment)? onAttachmentTap;
 
   ///
   MessageWidget({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.reverse = false,
     this.translateUserAvatar = true,
     this.shape,
@@ -197,7 +197,7 @@ class MessageWidget extends StatefulWidget {
     this.editMessageInputBuilder,
     this.textBuilder,
     this.onReturnAction,
-    Map<String, AttachmentBuilder> customAttachmentBuilders,
+    Map<String, AttachmentBuilder>? customAttachmentBuilders,
     this.readList,
     this.padding,
     this.textPadding = const EdgeInsets.symmetric(
@@ -222,7 +222,7 @@ class MessageWidget extends StatefulWidget {
                 child: wrapAttachmentWidget(
                   context,
                   Material(
-                    color: messageTheme.messageBackgroundColor,
+                    color: messageTheme?.messageBackgroundColor,
                     child: ImageGroup(
                       size: Size(
                         MediaQuery.of(context).size.width * 0.8,
@@ -236,7 +236,8 @@ class MessageWidget extends StatefulWidget {
                   ),
                   border,
                   reverse,
-                  attachmentBorderRadiusGeometry ?? BorderRadius.zero,
+                  attachmentBorderRadiusGeometry as BorderRadius? ??
+                      BorderRadius.zero,
                 ),
               );
             }
@@ -255,13 +256,14 @@ class MessageWidget extends StatefulWidget {
                 onReturnAction: onReturnAction,
                 onAttachmentTap: onAttachmentTap != null
                     ? () {
-                        onAttachmentTap?.call(message, attachments[0]);
+                        onAttachmentTap.call(message, attachments[0]);
                       }
                     : null,
               ),
               border,
               reverse,
-              attachmentBorderRadiusGeometry ?? BorderRadius.zero,
+              attachmentBorderRadiusGeometry as BorderRadius? ??
+                  BorderRadius.zero,
             );
           },
           'video': (context, message, attachments) {
@@ -286,7 +288,7 @@ class MessageWidget extends StatefulWidget {
                     onReturnAction: onReturnAction,
                     onAttachmentTap: onAttachmentTap != null
                         ? () {
-                            onAttachmentTap?.call(message, attachment);
+                            onAttachmentTap(message, attachment);
                           }
                         : null,
                   );
@@ -294,11 +296,12 @@ class MessageWidget extends StatefulWidget {
               ),
               border,
               reverse,
-              attachmentBorderRadiusGeometry ?? BorderRadius.zero,
+              attachmentBorderRadiusGeometry as BorderRadius? ??
+                  BorderRadius.zero,
             );
           },
           'giphy': (context, message, attachments) {
-            var border = RoundedRectangleBorder(
+            final border = RoundedRectangleBorder(
               side: BorderSide.none,
               borderRadius: attachmentBorderRadiusGeometry ?? BorderRadius.zero,
             );
@@ -309,7 +312,6 @@ class MessageWidget extends StatefulWidget {
                 children: attachments.map((attachment) {
                   return GiphyAttachment(
                     attachment: attachment,
-                    messageTheme: messageTheme,
                     message: message,
                     size: Size(
                       MediaQuery.of(context).size.width * 0.8,
@@ -322,7 +324,8 @@ class MessageWidget extends StatefulWidget {
               ),
               border,
               reverse,
-              attachmentBorderRadiusGeometry ?? BorderRadius.zero,
+              attachmentBorderRadiusGeometry as BorderRadius? ??
+                  BorderRadius.zero,
             );
           },
           'file': (context, message, attachments) {
@@ -349,7 +352,8 @@ class MessageWidget extends StatefulWidget {
                       ),
                       border,
                       reverse,
-                      attachmentBorderRadiusGeometry ?? BorderRadius.zero,
+                      attachmentBorderRadiusGeometry as BorderRadius? ??
+                          BorderRadius.zero,
                     );
                   })
                   .insertBetween(SizedBox(
@@ -381,7 +385,7 @@ class _MessageWidgetState extends State<MessageWidget>
 
   bool get showInChannel => widget.showInChannelIndicator;
 
-  bool get hasQuotedMessage => widget.message?.quotedMessage != null;
+  bool get hasQuotedMessage => widget.message.quotedMessage != null;
 
   bool get isSendFailed => widget.message.status == MessageSendingStatus.failed;
 
@@ -394,17 +398,17 @@ class _MessageWidgetState extends State<MessageWidget>
   bool get isFailedState => isSendFailed || isUpdateFailed || isDeleteFailed;
 
   bool get isGiphy =>
-      widget.message.attachments?.any((element) => element.type == 'giphy') ==
+      widget.message.attachments.any((element) => element.type == 'giphy') ==
       true;
 
   bool get hasNonUrlAttachments =>
       widget.message.attachments
-          ?.where((it) => it.ogScrapeUrl == null)
+          .where((it) => it.ogScrapeUrl == null)
-          ?.isNotEmpty ==
+          .isNotEmpty ==
       true;
 
   bool get hasUrlAttachments =>
-      widget.message.attachments?.any((it) => it.ogScrapeUrl != null) == true;
+      widget.message.attachments.any((it) => it.ogScrapeUrl != null) == true;
 
   bool get showBottomRow =>
       showThreadReplyIndicator ||
@@ -415,12 +419,13 @@ class _MessageWidgetState extends State<MessageWidget>
       isDeleted;
 
   @override
-  bool get wantKeepAlive => widget.message.attachments?.isNotEmpty == true;
+  bool get wantKeepAlive => widget.message.attachments.isNotEmpty == true;
 
   @override
   Widget build(BuildContext context) {
     super.build(context);
-    final avatarWidth = widget.messageTheme.avatarTheme.constraints.maxWidth;
+    final avatarWidth =
+        widget.messageTheme?.avatarTheme?.constraints.maxWidth ?? 40;
     var leftPadding =
         widget.showUserAvatar != DisplayWidget.gone ? avatarWidth + 8.5 : 0.5;
 
@@ -429,7 +434,7 @@ class _MessageWidgetState extends State<MessageWidget>
       child: Portal(
         child: InkWell(
           onTap: () {
-            widget.onMessageTap(widget.message);
+            widget.onMessageTap!(widget.message);
           },
           onLongPress: widget.message.isDeleted && !isFailedState
               ? null
@@ -460,7 +465,8 @@ class _MessageWidgetState extends State<MessageWidget>
                               mainAxisSize: MainAxisSize.min,
                               children: <Widget>[
                                 if (widget.showUserAvatar ==
-                                    DisplayWidget.show) ...[
+                                        DisplayWidget.show &&
+                                    widget.message.user != null) ...[
                                   _buildUserAvatar(),
                                   SizedBox(width: 4),
                                 ],
@@ -533,13 +539,14 @@ class _MessageWidgetState extends State<MessageWidget>
                                                   ),
                                                   shape: widget.shape ??
                                                       RoundedRectangleBorder(
-                                                        side:
+                                                        side: widget
-                                                            widget.borderSide ??
+                                                                .borderSide ??
-                                                                BorderSide(
+                                                            BorderSide(
-                                                                  color: widget
+                                                              color: widget
                                                                       .messageTheme
-                                                                      .messageBorderColor,
+                                                                      ?.messageBorderColor ??
-                                                                ),
+                                                                  Colors.grey,
+                                                            ),
                                                         borderRadius: widget
                                                                 .borderRadiusGeometry ??
                                                             BorderRadius.zero,
@@ -616,14 +623,14 @@ class _MessageWidgetState extends State<MessageWidget>
 
   Widget _buildQuotedMessage() {
     final isMyMessage =
-        widget.message.user.id == StreamChat.of(context).user.id;
+        widget.message.user?.id == StreamChat.of(context).user?.id;
-    final onTap = widget.message?.quotedMessage?.isDeleted != true &&
+    final onTap = widget.message.quotedMessage?.isDeleted != true &&
             widget.onQuotedMessageTap != null
-        ? () => widget.onQuotedMessageTap(widget.message.quotedMessageId)
+        ? () => widget.onQuotedMessageTap!(widget.message.quotedMessageId)
         : null;
     return QuotedMessageWidget(
       onTap: onTap,
-      message: widget.message.quotedMessage,
+      message: widget.message.quotedMessage!,
       messageTheme: isMyMessage
           ? StreamChatTheme.of(context).otherMessageTheme
           : StreamChatTheme.of(context).ownMessageTheme,
@@ -660,12 +667,12 @@ class _MessageWidgetState extends State<MessageWidget>
 
     var children = <Widget>[];
 
-    final threadParticipants = widget.message?.threadParticipants?.take(2);
+    final threadParticipants = widget.message.threadParticipants?.take(2);
     final showThreadParticipants = threadParticipants?.isNotEmpty == true;
     final replyCount = widget.message.replyCount;
 
     var msg = 'Thread Reply';
-    if (showThreadReplyIndicator && replyCount > 1) {
+    if (showThreadReplyIndicator && replyCount! > 1) {
       msg = '$replyCount Thread Replies';
     }
 
@@ -674,9 +681,9 @@ class _MessageWidgetState extends State<MessageWidget>
         var message = widget.message;
         if (showInChannel) {
           final channel = StreamChannel.of(context);
-          message = await channel.getMessage(widget.message.parentId);
+          message = await channel.getMessage(widget.message.parentId!);
         }
-        return widget.onThreadTap(message);
+        return widget.onThreadTap!(message);
       } catch (e, stk) {
         print(e);
         print(stk);
@@ -690,7 +697,7 @@ class _MessageWidgetState extends State<MessageWidget>
       if (showInChannel || showThreadReplyIndicator) ...[
         if (showThreadParticipants)
           SizedBox.fromSize(
-            size: Size((threadParticipants.length * 8.0) + 8, 16),
+            size: Size((threadParticipants!.length * 8.0) + 8, 16),
             child: _buildThreadParticipantsIndicator(threadParticipants),
           ),
         InkWell(
@@ -700,16 +707,16 @@ class _MessageWidgetState extends State<MessageWidget>
       ],
       if (showUsername)
         Text(
-          widget.message.user.name,
+          widget.message.user!.name,
           maxLines: 1,
           key: usernameKey,
-          style: widget.messageTheme.messageAuthor,
+          style: widget.messageTheme?.messageAuthor,
           overflow: TextOverflow.ellipsis,
         ),
       if (showTimeStamp)
         Text(
           Jiffy(widget.message.createdAt.toLocal()).jm,
-          style: widget.messageTheme.createdAt,
+          style: widget.messageTheme?.createdAt,
         ),
       if (showSendingIndicator) _buildSendingIndicator(),
     ]);
@@ -724,13 +731,13 @@ class _MessageWidgetState extends State<MessageWidget>
           Container(
             margin: EdgeInsets.only(
               bottom: context.textScaleFactor *
-                  (widget.messageTheme.replies.fontSize / 2),
+                  ((widget.messageTheme?.replies?.fontSize ?? 1) / 2),
             ),
             child: CustomPaint(
               size: Size(16, 32) * context.textScaleFactor,
               painter: _ThreadReplyPainter(
                 context: context,
-                color: widget.messageTheme.messageBorderColor,
+                color: widget.messageTheme?.messageBorderColor,
               ),
             ),
           ),
@@ -758,7 +765,7 @@ class _MessageWidgetState extends State<MessageWidget>
     var urlAttachment = widget.message.attachments
         .firstWhere((element) => element.ogScrapeUrl != null);
 
-    var host = Uri.parse(urlAttachment.ogScrapeUrl).host;
+    var host = Uri.parse(urlAttachment.ogScrapeUrl!).host;
     var splitList = host.split('.');
     var hostName = splitList.length == 3 ? splitList[1] : splitList[0];
     var hostDisplayName = urlAttachment.authorName?.capitalize() ??
@@ -768,7 +775,7 @@ class _MessageWidgetState extends State<MessageWidget>
     return UrlAttachment(
       urlAttachment: urlAttachment,
       hostDisplayName: hostDisplayName,
-      textPadding: widget.textPadding,
+      textPadding: widget.textPadding as EdgeInsets,
     );
   }
 
@@ -801,15 +808,16 @@ class _MessageWidgetState extends State<MessageWidget>
   Widget _buildReactionIndicator(
     BuildContext context,
   ) {
-    final ownId = StreamChat.of(context).user.id;
+    final ownId = StreamChat.of(context).user!.id;
     final reactionsMap = <String, Reaction>{};
     widget.message.latestReactions?.forEach((element) {
-      if (!reactionsMap.containsKey(element.type) || element.user.id == ownId) {
+      if (!reactionsMap.containsKey(element.type) ||
+          element.user!.id == ownId) {
         reactionsMap[element.type] = element;
       }
     });
     final reactionsList = reactionsMap.values.toList()
-      ..sort((a, b) => a.user.id == ownId ? 1 : -1);
+      ..sort((a, b) => a.user!.id == ownId ? 1 : -1);
 
     return AnimatedSwitcher(
       duration: Duration(milliseconds: 300),
@@ -822,9 +830,13 @@ class _MessageWidgetState extends State<MessageWidget>
                 key: ValueKey('${widget.message.id}.reactions'),
                 reverse: widget.reverse,
                 flipTail: widget.reverse,
-                backgroundColor: widget.messageTheme.reactionsBackgroundColor,
+                backgroundColor:
-                borderColor: widget.messageTheme.reactionsBorderColor,
+                    widget.messageTheme?.reactionsBackgroundColor ??
-                maskColor: widget.messageTheme.reactionsMaskColor,
+                        Colors.transparent,
+                borderColor: widget.messageTheme?.reactionsBorderColor ??
+                    Colors.transparent,
+                maskColor: widget.messageTheme?.reactionsMaskColor ??
+                    Colors.transparent,
                 reactions: reactionsList,
               ),
             )
@@ -845,9 +857,9 @@ class _MessageWidgetState extends State<MessageWidget>
               onCopyTap: (message) =>
                   Clipboard.setData(ClipboardData(text: message.text)),
               attachmentBorderRadiusGeometry:
-                  widget.attachmentBorderRadiusGeometry,
+                  widget.attachmentBorderRadiusGeometry as BorderRadius?,
               showUserAvatar:
-                  widget.message.user.id == channel.client.state.user.id
+                  widget.message.user!.id == channel.client.state.user!.id
                       ? DisplayWidget.gone
                       : DisplayWidget.show,
               messageTheme: widget.messageTheme,
@@ -864,11 +876,11 @@ class _MessageWidgetState extends State<MessageWidget>
                   widget.showResendMessage && (isSendFailed || isUpdateFailed),
               showCopyMessage: widget.showCopyMessage &&
                   !isFailedState &&
-                  widget.message.text?.trim()?.isNotEmpty == true,
+                  widget.message.text?.trim().isNotEmpty == true,
               showEditMessage: widget.showEditMessage &&
                   !isDeleteFailed &&
                   widget.message.attachments
-                          ?.any((element) => element.type == 'giphy') !=
+                          .any((element) => element.type == 'giphy') !=
                       true,
               showReactions: widget.showReactions,
               showReplyMessage: widget.showReplyMessage &&
@@ -894,9 +906,9 @@ class _MessageWidgetState extends State<MessageWidget>
             channel: channel,
             child: MessageReactionsModal(
               attachmentBorderRadiusGeometry:
-                  widget.attachmentBorderRadiusGeometry,
+                  widget.attachmentBorderRadiusGeometry as BorderRadius?,
               showUserAvatar:
-                  widget.message.user.id == channel.client.state.user.id
+                  widget.message.user!.id == channel.client.state.user!.id
                       ? DisplayWidget.gone
                       : DisplayWidget.show,
               onUserAvatarTap: widget.onUserAvatarTap,
@@ -914,7 +926,7 @@ class _MessageWidgetState extends State<MessageWidget>
 
   ShapeBorder _getDefaultAttachmentShape(BuildContext context) {
     final hasFiles =
-        widget.message.attachments?.any((it) => it.type == 'file') == true;
+        widget.message.attachments.any((it) => it.type == 'file') == true;
     return RoundedRectangleBorder(
       side: hasFiles
           ? widget.attachmentBorderSide ??
@@ -940,13 +952,13 @@ class _MessageWidgetState extends State<MessageWidget>
     final attachmentGroups = <String, List<Attachment>>{};
 
     widget.message.attachments
-        .where((element) => element.ogScrapeUrl == null)
+        .where((element) => element.ogScrapeUrl == null && element.type != null)
         .forEach((e) {
       if (attachmentGroups[e.type] == null) {
-        attachmentGroups[e.type] = [];
+        attachmentGroups[e.type!] = [];
       }
 
-      attachmentGroups[e.type].add(e);
+      attachmentGroups[e.type]?.add(e);
     });
 
     final attachmentList = <Widget>[];
@@ -954,7 +966,7 @@ class _MessageWidgetState extends State<MessageWidget>
     attachmentGroups.forEach((type, attachments) {
       final attachmentBuilder = widget.attachmentBuilders[type];
 
-      if (attachmentBuilder == null) return SizedBox();
+      if (attachmentBuilder == null) return;
       final attachmentWidget = attachmentBuilder(
         context,
         widget.message,
@@ -967,10 +979,9 @@ class _MessageWidgetState extends State<MessageWidget>
       padding: widget.attachmentPadding,
       child: Column(
         mainAxisSize: MainAxisSize.min,
-        children: attachmentList?.insertBetween(SizedBox(
+        children: attachmentList.insertBetween(SizedBox(
-              height: widget.attachmentPadding.vertical / 2,
+          height: widget.attachmentPadding.vertical / 2,
-            )) ??
+        )),
-            [],
       ),
     );
   }
@@ -982,7 +993,7 @@ class _MessageWidgetState extends State<MessageWidget>
     }
 
     if (widget.onMessageActions != null) {
-      widget.onMessageActions(context, widget.message);
+      widget.onMessageActions!(context, widget.message);
     } else {
       _showMessageActionModalBottomSheet(context);
     }
@@ -990,7 +1001,7 @@ class _MessageWidgetState extends State<MessageWidget>
   }
 
   Widget _buildSendingIndicator() {
-    final style = widget.messageTheme.createdAt;
+    final style = widget.messageTheme?.createdAt;
     final message = widget.message;
 
     if (hasNonUrlAttachments &&
@@ -1002,8 +1013,8 @@ class _MessageWidgetState extends State<MessageWidget>
       }).length;
       if (uploadRemaining == 0) {
         return StreamSvgIcon.check(
-          size: style.fontSize,
+          size: style!.fontSize,
-          color: IconTheme.of(context).color.withOpacity(0.5),
+          color: IconTheme.of(context).color!.withOpacity(0.5),
         );
       }
       return Text(
@@ -1015,14 +1026,14 @@ class _MessageWidgetState extends State<MessageWidget>
     Widget child = SendingIndicator(
       message: message,
       isMessageRead: isMessageRead,
-      size: style.fontSize,
+      size: style!.fontSize,
     );
     if (isMessageRead) {
       child = Row(
         children: [
-          if (StreamChannel.of(context).channel.memberCount > 2)
+          if (StreamChannel.of(context).channel.memberCount! > 2)
             Text(
-              widget.readList.length.toString(),
+              widget.readList!.length.toString(),
               style: style.copyWith(
                 color: StreamChatTheme.of(context).colorTheme.accentBlue,
               ),
@@ -1042,21 +1053,23 @@ class _MessageWidgetState extends State<MessageWidget>
           offset: Offset(
             0,
             widget.translateUserAvatar
-                ? widget.messageTheme.avatarTheme.constraints.maxHeight / 2
+                ? (widget.messageTheme?.avatarTheme?.constraints.maxHeight ??
+                        40) /
+                    2
                 : 0,
           ),
           child: UserAvatar(
-            user: widget.message.user,
+            user: widget.message.user!,
             onTap: widget.onUserAvatarTap,
-            constraints: widget.messageTheme.avatarTheme.constraints,
+            constraints: widget.messageTheme?.avatarTheme!.constraints,
-            borderRadius: widget.messageTheme.avatarTheme.borderRadius,
+            borderRadius: widget.messageTheme?.avatarTheme!.borderRadius,
             showOnlineStatus: false,
           ),
         ),
       );
 
   Widget _buildTextBubble() {
-    if (widget.message.text.trim().isEmpty) return Offstage();
+    if (widget.message.text!.trim().isEmpty) return Offstage();
     return Transform(
       transform: Matrix4.rotationY(widget.reverse ? pi : 0),
       alignment: Alignment.center,
@@ -1066,15 +1079,15 @@ class _MessageWidgetState extends State<MessageWidget>
           Padding(
             padding: isOnlyEmoji ? EdgeInsets.zero : widget.textPadding,
             child: widget.textBuilder != null
-                ? widget.textBuilder(context, widget.message)
+                ? widget.textBuilder!(context, widget.message)
                 : MessageText(
                     onLinkTap: widget.onLinkTap,
                     message: widget.message,
                     onMentionTap: widget.onMentionTap,
                     messageTheme: isOnlyEmoji
-                        ? widget.messageTheme.copyWith(
+                        ? widget.messageTheme?.copyWith(
                             messageText:
-                                widget.messageTheme.messageText.copyWith(
+                                widget.messageTheme?.messageText!.copyWith(
                             fontSize: 42,
                           ))
                         : widget.messageTheme,
@@ -1086,11 +1099,11 @@ class _MessageWidgetState extends State<MessageWidget>
     );
   }
 
-  bool get isOnlyEmoji => widget.message.text.isOnlyEmoji;
+  bool get isOnlyEmoji => widget.message.text!.isOnlyEmoji;
 
-  Color _getBackgroundColor() {
+  Color? _getBackgroundColor() {
     if (hasQuotedMessage) {
-      return widget.messageTheme.messageBackgroundColor;
+      return widget.messageTheme?.messageBackgroundColor;
     }
 
     if (hasUrlAttachments) {
@@ -1105,7 +1118,7 @@ class _MessageWidgetState extends State<MessageWidget>
       return Colors.transparent;
     }
 
-    return widget.messageTheme.messageBackgroundColor;
+    return widget.messageTheme?.messageBackgroundColor;
   }
 
   void retryMessage(BuildContext context) {
@@ -1127,15 +1140,15 @@ class _MessageWidgetState extends State<MessageWidget>
 }
 
 class _ThreadReplyPainter extends CustomPainter {
-  final Color color;
+  final Color? color;
-  final BuildContext context;
+  final BuildContext? context;
 
-  const _ThreadReplyPainter({this.context, @required this.color});
+  const _ThreadReplyPainter({this.context, required this.color});
 
   @override
   void paint(Canvas canvas, Size size) {
     final paint = Paint()
-      ..color = color ?? StreamChatTheme.of(context).colorTheme.greyGainsboro
+      ..color = color ?? StreamChatTheme.of(context!).colorTheme.greyGainsboro
       ..style = PaintingStyle.stroke
       ..strokeWidth = 1
       ..strokeCap = StrokeCap.round;

packages/stream_chat_flutter/lib/src/option_list_tile.dart

@@ -2,14 +2,14 @@ import 'package:flutter/material.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 
 class OptionListTile extends StatelessWidget {
-  final String title;
+  final String? title;
-  final Widget leading;
+  final Widget? leading;
-  final Widget trailing;
+  final Widget? trailing;
-  final VoidCallback onTap;
+  final VoidCallback? onTap;
-  final Color titleColor;
+  final Color? titleColor;
-  final Color tileColor;
+  final Color? tileColor;
-  final Color separatorColor;
+  final Color? separatorColor;
-  final TextStyle titleTextStyle;
+  final TextStyle? titleTextStyle;
 
   OptionListTile({
     this.title,
@@ -47,7 +47,7 @@ class OptionListTile extends StatelessWidget {
                   Expanded(
                     flex: 4,
                     child: Text(
-                      title,
+                      title!,
                       style: titleTextStyle ??
                           (titleColor == null
                               ? StreamChatTheme.of(context).textTheme.bodyBold

packages/stream_chat_flutter/lib/src/quoted_message_widget.dart

@@ -22,8 +22,8 @@ class _VideoAttachmentThumbnail extends StatefulWidget {
   final Attachment attachment;
 
   const _VideoAttachmentThumbnail({
-    Key key,
+    Key? key,
-    @required this.attachment,
+    required this.attachment,
     this.size = const Size(32, 32),
   }) : super(key: key);
 
@@ -33,12 +33,12 @@ class _VideoAttachmentThumbnail extends StatefulWidget {
 }
 
 class _VideoAttachmentThumbnailState extends State<_VideoAttachmentThumbnail> {
-  VideoPlayerController _controller;
+  late VideoPlayerController _controller;
 
   @override
   void initState() {
     super.initState();
-    _controller = VideoPlayerController.network(widget.attachment.assetUrl)
+    _controller = VideoPlayerController.network(widget.attachment.assetUrl!)
       ..initialize().then((_) {
         setState(() {}); //when your thumbnail will show.
       });
@@ -67,7 +67,7 @@ class QuotedMessageWidget extends StatelessWidget {
   final Message message;
 
   /// The message theme
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
 
   /// If true the widget will be mirrored
   final bool reverse;
@@ -79,18 +79,18 @@ class QuotedMessageWidget extends StatelessWidget {
   final int textLimit;
 
   /// Map that defines a thumbnail builder for an attachment type
-  final Map<String, QuotedMessageAttachmentThumbnailBuilder>
+  final Map<String, QuotedMessageAttachmentThumbnailBuilder>?
       attachmentThumbnailBuilders;
 
   final EdgeInsetsGeometry padding;
 
-  final GestureTapCallback onTap;
+  final GestureTapCallback? onTap;
 
   ///
   QuotedMessageWidget({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
     this.reverse = false,
     this.showBorder = false,
     this.textLimit = 170,
@@ -99,13 +99,12 @@ class QuotedMessageWidget extends StatelessWidget {
     this.onTap,
   }) : super(key: key);
 
-  bool get _hasAttachments => message.attachments?.isNotEmpty == true;
+  bool get _hasAttachments => message.attachments.isNotEmpty == true;
 
   bool get _containsScrapeUrl =>
-      message.attachments?.any((element) => element.ogScrapeUrl != null) ==
+      message.attachments.any((element) => element.ogScrapeUrl != null) == true;
-      true;
 
-  bool get _containsText => message?.text?.isNotEmpty == true;
+  bool get _containsText => message.text?.isNotEmpty == true;
 
   @override
   Widget build(BuildContext context) {
@@ -119,7 +118,7 @@ class QuotedMessageWidget extends StatelessWidget {
           children: [
             Flexible(child: _buildMessage(context)),
             SizedBox(width: 8),
-            _buildUserAvatar(),
+            if (message.user != null) _buildUserAvatar(),
           ],
         ),
       ),
@@ -127,17 +126,17 @@ class QuotedMessageWidget extends StatelessWidget {
   }
 
   Widget _buildMessage(BuildContext context) {
-    final isOnlyEmoji = message.text.isOnlyEmoji;
+    final isOnlyEmoji = message.text!.isOnlyEmoji;
     var msg = _hasAttachments && !_containsText
-        ? message.copyWith(text: message.attachments.last?.title ?? '')
+        ? message.copyWith(text: message.attachments.last.title ?? '')
         : message;
-    if (msg.text.length > textLimit) {
+    if (msg.text!.length > textLimit) {
-      msg = msg.copyWith(text: '${msg.text.substring(0, textLimit - 3)}...');
+      msg = msg.copyWith(text: '${msg.text!.substring(0, textLimit - 3)}...');
     }
 
     final children = [
       if (_hasAttachments) _parseAttachments(context),
-      if (msg.text.isNotEmpty)
+      if (msg.text!.isNotEmpty)
         Flexible(
           child: Transform(
             transform: Matrix4.rotationY(reverse ? pi : 0),
@@ -145,12 +144,12 @@ class QuotedMessageWidget extends StatelessWidget {
             child: MessageText(
               message: msg,
               messageTheme: isOnlyEmoji && _containsText
-                  ? messageTheme.copyWith(
+                  ? messageTheme?.copyWith(
-                      messageText: messageTheme.messageText.copyWith(
+                      messageText: messageTheme?.messageText?.copyWith(
                       fontSize: 32,
                     ))
-                  : messageTheme.copyWith(
+                  : messageTheme?.copyWith(
-                      messageText: messageTheme.messageText.copyWith(
+                      messageText: messageTheme?.messageText?.copyWith(
                       fontSize: 12,
                     )),
             ),
@@ -193,7 +192,7 @@ class QuotedMessageWidget extends StatelessWidget {
           image: DecorationImage(
             fit: BoxFit.cover,
             image: CachedNetworkImageProvider(
-              attachment.imageUrl,
+              attachment.imageUrl!,
             ),
           ),
         ),
@@ -211,16 +210,16 @@ class QuotedMessageWidget extends StatelessWidget {
       );
       child = _buildUrlAttachment(attachment);
     } else {
-      QuotedMessageAttachmentThumbnailBuilder attachmentBuilder;
+      QuotedMessageAttachmentThumbnailBuilder? attachmentBuilder;
       attachment = message.attachments.last;
-      if (attachmentThumbnailBuilders?.containsKey(attachment?.type) == true) {
+      if (attachmentThumbnailBuilders?.containsKey(attachment.type) == true) {
-        attachmentBuilder = attachmentThumbnailBuilders[attachment?.type];
+        attachmentBuilder = attachmentThumbnailBuilders![attachment.type];
       }
-      attachmentBuilder = _defaultAttachmentBuilder[attachment?.type];
+      attachmentBuilder = _defaultAttachmentBuilder[attachment.type];
       if (attachmentBuilder == null) {
         child = Offstage();
       }
-      child = attachmentBuilder(context, attachment);
+      child = attachmentBuilder!(context, attachment);
     }
     child = AbsorbPointer(child: child);
     return Transform(
@@ -247,7 +246,7 @@ class QuotedMessageWidget extends StatelessWidget {
       transform: Matrix4.rotationY(reverse ? pi : 0),
       alignment: Alignment.center,
       child: UserAvatar(
-        user: message.user,
+        user: message.user!,
         constraints: BoxConstraints.tightFor(
           height: 24,
           width: 24,
@@ -277,19 +276,20 @@ class QuotedMessageWidget extends StatelessWidget {
       'giphy': (_, attachment) {
         final size = Size(32, 32);
         return CachedNetworkImage(
-          height: size?.height,
+          height: size.height,
-          width: size?.width,
+          width: size.width,
           placeholder: (_, __) {
             return Container(
-              width: size?.width,
+              width: size.width,
-              height: size?.height,
+              height: size.height,
               child: Center(
                 child: CircularProgressIndicator(),
               ),
             );
           },
-          imageUrl:
+          imageUrl: attachment.thumbUrl ??
-              attachment.thumbUrl ?? attachment.imageUrl ?? attachment.assetUrl,
+              attachment.imageUrl ??
+              attachment.assetUrl!,
           errorWidget: (context, url, error) {
             return AttachmentError(size: size);
           },
@@ -300,16 +300,16 @@ class QuotedMessageWidget extends StatelessWidget {
         return Container(
           height: 32,
           width: 32,
-          child: getFileTypeImage(attachment.extraData['mime_type']),
+          child: getFileTypeImage(attachment.extraData['mime_type'] as String?),
         );
       },
     };
   }
 
-  Color _getBackgroundColor(BuildContext context) {
+  Color? _getBackgroundColor(BuildContext context) {
     if (_containsScrapeUrl) {
       return StreamChatTheme.of(context).colorTheme.blueAlice;
     }
-    return messageTheme.messageBackgroundColor;
+    return messageTheme?.messageBackgroundColor;
   }
 }

packages/stream_chat_flutter/lib/src/reaction_bubble.dart

@@ -1,5 +1,6 @@
 import 'dart:math';
 
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
@@ -9,11 +10,11 @@ import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 class ReactionBubble extends StatelessWidget {
   const ReactionBubble({
-    Key key,
+    Key? key,
-    @required this.reactions,
+    required this.reactions,
-    @required this.borderColor,
+    required this.borderColor,
-    @required this.backgroundColor,
+    required this.backgroundColor,
-    @required this.maskColor,
+    required this.maskColor,
     this.reverse = false,
     this.flipTail = false,
     this.highlightOwnReactions = true,
@@ -108,9 +109,8 @@ class ReactionBubble extends StatelessWidget {
     Reaction reaction,
     BuildContext context,
   ) {
-    final reactionIcon = reactionIcons.firstWhere(
+    final reactionIcon = reactionIcons.firstWhereOrNull(
       (r) => r.type == reaction.type,
-      orElse: () => null,
     );
 
     return Padding(
@@ -123,7 +123,7 @@ class ReactionBubble extends StatelessWidget {
               width: 16,
               height: 16,
               color: (!highlightOwnReactions ||
-                      reaction.user.id == StreamChat.of(context).user.id)
+                      reaction.user?.id == StreamChat.of(context).user?.id)
                   ? StreamChatTheme.of(context).colorTheme.accentBlue
                   : StreamChatTheme.of(context)
                       .colorTheme
@@ -134,7 +134,7 @@ class ReactionBubble extends StatelessWidget {
               Icons.help_outline_rounded,
               size: 16,
               color: (!highlightOwnReactions ||
-                      reaction.user.id == StreamChat.of(context).user.id)
+                      reaction.user?.id == StreamChat.of(context).user?.id)
                   ? StreamChatTheme.of(context).colorTheme.accentBlue
                   : StreamChatTheme.of(context)
                       .colorTheme

packages/stream_chat_flutter/lib/src/reaction_icon.dart

@@ -3,7 +3,7 @@ class ReactionIcon {
   final String assetName;
 
   ReactionIcon({
-    this.type,
+    required this.type,
-    this.assetName,
+    required this.assetName,
   });
 }

packages/stream_chat_flutter/lib/src/reaction_picker.dart

@@ -16,13 +16,13 @@ import 'extension.dart';
 
 class ReactionPicker extends StatefulWidget {
   const ReactionPicker({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
-    @required this.messageTheme,
+    required this.messageTheme,
   }) : super(key: key);
 
   final Message message;
-  final MessageTheme messageTheme;
+  final MessageTheme? messageTheme;
 
   @override
   _ReactionPickerState createState() => _ReactionPickerState();
@@ -98,7 +98,8 @@ class _ReactionPickerState extends State<ReactionPicker>
                               if (ownReactionIndex != -1) {
                                 removeReaction(
                                   context,
-                                  widget.message.ownReactions[ownReactionIndex],
+                                  widget
+                                      .message.ownReactions![ownReactionIndex],
                                 );
                               } else {
                                 sendReaction(
@@ -129,7 +130,7 @@ class _ReactionPickerState extends State<ReactionPicker>
                                               .accentBlue
                                           : Theme.of(context)
                                               .iconTheme
-                                              .color
+                                              .color!
                                               .withOpacity(.5),
                                     ),
                                   );
@@ -181,7 +182,7 @@ class _ReactionPickerState extends State<ReactionPicker>
   @override
   void dispose() {
     for (var a in animations) {
-      a?.dispose();
+      a.dispose();
     }
     super.dispose();
   }

packages/stream_chat_flutter/lib/src/sending_indicator.dart

@@ -5,11 +5,11 @@ import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 class SendingIndicator extends StatelessWidget {
   final Message message;
   final bool isMessageRead;
-  final double size;
+  final double? size;
 
   const SendingIndicator({
-    Key key,
+    Key? key,
-    this.message,
+    required this.message,
     this.isMessageRead = false,
     this.size = 12,
   }) : super(key: key);
@@ -22,10 +22,10 @@ class SendingIndicator extends StatelessWidget {
         color: StreamChatTheme.of(context).colorTheme.accentBlue,
       );
     }
-    if (message.status == MessageSendingStatus.sent || message.status == null) {
+    if (message.status == MessageSendingStatus.sent) {
       return StreamSvgIcon.check(
         size: size,
-        color: IconTheme.of(context).color.withOpacity(0.5),
+        color: IconTheme.of(context).color!.withOpacity(0.5),
       );
     }
     if (message.status == MessageSendingStatus.sending ||

packages/stream_chat_flutter/lib/src/stream_chat.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:ui' as ui;
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
@@ -7,7 +8,6 @@ import 'package:jiffy/jiffy.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
-import 'dart:ui' as ui;
 
 /// Widget used to provide information about the chat to the widget tree
 ///
@@ -32,8 +32,8 @@ import 'dart:ui' as ui;
 /// Use [StreamChat.of] to get the current [StreamChatState] instance.
 class StreamChat extends StatefulWidget {
   final StreamChatClient client;
-  final Widget child;
+  final Widget? child;
-  final StreamChatThemeData streamChatThemeData;
+  final StreamChatThemeData? streamChatThemeData;
 
   /// The amount of time that will pass before disconnecting the client in the background
   final Duration backgroundKeepAlive;
@@ -41,12 +41,12 @@ class StreamChat extends StatefulWidget {
   /// Handler called whenever the [client] receives a new [Event] while the app
   /// is in background. Can be used to display various notifications depending
   /// upon the [Event.type]
-  final EventHandler onBackgroundEventReceived;
+  final EventHandler? onBackgroundEventReceived;
 
   StreamChat({
-    Key key,
+    Key? key,
-    @required this.client,
+    required this.client,
-    @required this.child,
+    required this.child,
     this.streamChatThemeData,
     this.onBackgroundEventReceived,
     this.backgroundKeepAlive = const Duration(minutes: 1),
@@ -59,7 +59,7 @@ class StreamChat extends StatefulWidget {
 
   /// Use this method to get the current [StreamChatState] instance
   static StreamChatState of(BuildContext context) {
-    StreamChatState streamChatState;
+    StreamChatState? streamChatState;
 
     streamChatState = context.findAncestorStateOfType<StreamChatState>();
 
@@ -96,7 +96,7 @@ class StreamChatState extends State<StreamChat> {
                 client: client,
                 onBackgroundEventReceived: widget.onBackgroundEventReceived,
                 backgroundKeepAlive: widget.backgroundKeepAlive,
-                child: widget.child,
+                child: widget.child!,
               ),
             );
           },
@@ -107,17 +107,18 @@ class StreamChatState extends State<StreamChat> {
 
   StreamChatThemeData _getTheme(
     BuildContext context,
-    StreamChatThemeData themeData,
+    StreamChatThemeData? themeData,
   ) {
-    final defaultTheme = StreamChatThemeData.getDefaultTheme(Theme.of(context));
+    final appBrightness = Theme.of(context).brightness;
-    return defaultTheme.merge(themeData) ?? themeData;
+    final defaultTheme = StreamChatThemeData(brightness: appBrightness);
+    return defaultTheme.merge(themeData);
   }
 
   /// The current user
-  User get user => widget.client.state.user;
+  User? get user => widget.client.state.user;
 
   /// The current user as a stream
-  Stream<User> get userStream => widget.client.state.userStream;
+  Stream<User?> get userStream => widget.client.state.userStream;
 
   @override
   void initState() {

packages/stream_chat_flutter/lib/src/stream_chat_theme.dart

@@ -2,10 +2,11 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:stream_chat_flutter/src/channel_header.dart';
 import 'package:stream_chat_flutter/src/channel_preview.dart';
+import 'package:stream_chat_flutter/src/extension.dart';
 import 'package:stream_chat_flutter/src/message_input.dart';
 import 'package:stream_chat_flutter/src/reaction_icon.dart';
 import 'package:stream_chat_flutter/src/utils.dart';
-import 'package:stream_chat_flutter/src/extension.dart';
+import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 /// Inherited widget providing the [StreamChatThemeData] to the widget tree
@@ -13,9 +14,9 @@ class StreamChatTheme extends InheritedWidget {
   final StreamChatThemeData data;
 
   StreamChatTheme({
-    Key key,
+    Key? key,
-    @required this.data,
+    required this.data,
-    Widget child,
+    required Widget child,
   }) : super(
           key: key,
           child: child,
@@ -31,13 +32,12 @@ class StreamChatTheme extends InheritedWidget {
     final streamChatTheme =
         context.dependOnInheritedWidgetOfExactType<StreamChatTheme>();
 
-    if (streamChatTheme == null) {
+    assert(
-      throw Exception(
+      streamChatTheme != null,
-        'You must have a StreamChatTheme widget at the top of your widget tree',
+      'You must have a StreamChatTheme widget at the top of your widget tree',
-      );
+    );
-    }
 
-    return streamChatTheme.data;
+    return streamChatTheme!.data;
   }
 }
 
@@ -80,49 +80,96 @@ class StreamChatThemeData {
   final List<ReactionIcon> reactionIcons;
 
   /// Create a theme from scratch
-  const StreamChatThemeData({
+  factory StreamChatThemeData({
-    this.textTheme,
+    Brightness? brightness,
-    this.colorTheme,
+    TextTheme? textTheme,
-    this.channelListHeaderTheme,
+    ColorTheme? colorTheme,
-    this.channelPreviewTheme,
+    ChannelListHeaderTheme? channelListHeaderTheme,
-    this.channelTheme,
+    ChannelPreviewTheme? channelPreviewTheme,
-    this.otherMessageTheme,
+    ChannelTheme? channelTheme,
-    this.ownMessageTheme,
+    MessageTheme? otherMessageTheme,
-    this.messageInputTheme,
+    MessageTheme? ownMessageTheme,
-    this.defaultChannelImage,
+    MessageInputTheme? messageInputTheme,
-    this.defaultUserImage,
+    Widget Function(BuildContext, Channel)? defaultChannelImage,
-    this.primaryIconTheme,
+    Widget Function(BuildContext, User)? defaultUserImage,
-    this.reactionIcons,
+    IconThemeData? primaryIconTheme,
+    List<ReactionIcon>? reactionIcons,
+  }) {
+    brightness ??= colorTheme?.brightness ?? Brightness.light;
+    final isDark = brightness == Brightness.dark;
+    textTheme ??= isDark ? TextTheme.dark() : TextTheme.light();
+    colorTheme ??= isDark ? ColorTheme.dark() : ColorTheme.light();
+
+    final defaultData = fromColorAndTextTheme(
+      colorTheme,
+      textTheme,
+    );
+
+    final customizedData = defaultData.copyWith(
+      channelListHeaderTheme: channelListHeaderTheme,
+      channelPreviewTheme: channelPreviewTheme,
+      channelTheme: channelTheme,
+      otherMessageTheme: otherMessageTheme,
+      ownMessageTheme: ownMessageTheme,
+      messageInputTheme: messageInputTheme,
+      defaultChannelImage: defaultChannelImage,
+      defaultUserImage: defaultUserImage,
+      primaryIconTheme: primaryIconTheme,
+      reactionIcons: reactionIcons,
+    );
+
+    return defaultData.merge(customizedData);
+  }
+
+  factory StreamChatThemeData.light() =>
+      StreamChatThemeData(brightness: Brightness.light);
+
+  factory StreamChatThemeData.dark() =>
+      StreamChatThemeData(brightness: Brightness.dark);
+
+  const StreamChatThemeData.raw({
+    required this.textTheme,
+    required this.colorTheme,
+    required this.channelListHeaderTheme,
+    required this.channelPreviewTheme,
+    required this.channelTheme,
+    required this.otherMessageTheme,
+    required this.ownMessageTheme,
+    required this.messageInputTheme,
+    required this.defaultChannelImage,
+    required this.defaultUserImage,
+    required this.primaryIconTheme,
+    required this.reactionIcons,
   });
 
   /// Create a theme from a Material [Theme]
   factory StreamChatThemeData.fromTheme(ThemeData theme) {
-    final defaultTheme = getDefaultTheme(theme);
+    final defaultTheme = StreamChatThemeData(brightness: theme.brightness);
     final customizedTheme = StreamChatThemeData.fromColorAndTextTheme(
       defaultTheme.colorTheme.copyWith(
         accentBlue: theme.accentColor,
       ),
       defaultTheme.textTheme,
     );
-    return defaultTheme.merge(customizedTheme) ?? customizedTheme;
+    return defaultTheme.merge(customizedTheme);
   }
 
   /// Creates a copy of [StreamChatThemeData] with specified attributes overridden.
   StreamChatThemeData copyWith({
-    TextTheme textTheme,
+    TextTheme? textTheme,
-    ColorTheme colorTheme,
+    ColorTheme? colorTheme,
-    ChannelPreviewTheme channelPreviewTheme,
+    ChannelPreviewTheme? channelPreviewTheme,
-    ChannelTheme channelTheme,
+    ChannelTheme? channelTheme,
-    MessageTheme ownMessageTheme,
+    MessageTheme? ownMessageTheme,
-    MessageTheme otherMessageTheme,
+    MessageTheme? otherMessageTheme,
-    MessageInputTheme messageInputTheme,
+    MessageInputTheme? messageInputTheme,
-    Widget Function(BuildContext, Channel) defaultChannelImage,
+    Widget Function(BuildContext, Channel)? defaultChannelImage,
-    Widget Function(BuildContext, User) defaultUserImage,
+    Widget Function(BuildContext, User)? defaultUserImage,
-    IconThemeData primaryIconTheme,
+    IconThemeData? primaryIconTheme,
-    ChannelListHeaderTheme channelListHeaderTheme,
+    ChannelListHeaderTheme? channelListHeaderTheme,
-    List<ReactionIcon> reactionIcons,
+    List<ReactionIcon>? reactionIcons,
   }) =>
-      StreamChatThemeData(
+      StreamChatThemeData.raw(
         channelListHeaderTheme:
             channelListHeaderTheme ?? this.channelListHeaderTheme,
         textTheme: textTheme ?? this.textTheme,
@@ -138,28 +185,21 @@ class StreamChatThemeData {
         reactionIcons: reactionIcons ?? this.reactionIcons,
       );
 
-  StreamChatThemeData merge(StreamChatThemeData other) {
+  StreamChatThemeData merge(StreamChatThemeData? other) {
     if (other == null) return this;
     return copyWith(
       channelListHeaderTheme:
-          channelListHeaderTheme?.merge(other.channelListHeaderTheme) ??
+          channelListHeaderTheme.merge(other.channelListHeaderTheme),
-              other.channelListHeaderTheme,
+      textTheme: textTheme.merge(other.textTheme),
-      textTheme: textTheme?.merge(other.textTheme) ?? other.textTheme,
+      colorTheme: colorTheme.merge(other.colorTheme),
-      colorTheme: colorTheme?.merge(other.colorTheme) ?? other.colorTheme,
       primaryIconTheme: other.primaryIconTheme,
       defaultChannelImage: other.defaultChannelImage,
       defaultUserImage: other.defaultUserImage,
-      channelPreviewTheme:
+      channelPreviewTheme: channelPreviewTheme.merge(other.channelPreviewTheme),
-          channelPreviewTheme?.merge(other.channelPreviewTheme) ??
+      channelTheme: channelTheme.merge(other.channelTheme),
-              other.channelPreviewTheme,
+      ownMessageTheme: ownMessageTheme.merge(other.ownMessageTheme),
-      channelTheme:
+      otherMessageTheme: otherMessageTheme.merge(other.otherMessageTheme),
-          channelTheme?.merge(other.channelTheme) ?? other.channelTheme,
+      messageInputTheme: messageInputTheme.merge(other.messageInputTheme),
-      ownMessageTheme: ownMessageTheme?.merge(other.ownMessageTheme) ??
-          other.ownMessageTheme,
-      otherMessageTheme: otherMessageTheme?.merge(other.otherMessageTheme) ??
-          other.otherMessageTheme,
-      messageInputTheme: messageInputTheme?.merge(other.messageInputTheme) ??
-          other.messageInputTheme,
       reactionIcons: other.reactionIcons,
     );
   }
@@ -169,7 +209,7 @@ class StreamChatThemeData {
     TextTheme textTheme,
   ) {
     final accentColor = colorTheme.accentBlue;
-    return StreamChatThemeData(
+    return StreamChatThemeData.raw(
       textTheme: textTheme,
       colorTheme: colorTheme,
       primaryIconTheme: IconThemeData(color: colorTheme.black.withOpacity(.5)),
@@ -314,22 +354,6 @@ class StreamChatThemeData {
       ],
     );
   }
-
-  /// Get the default Stream Chat theme
-  static StreamChatThemeData getDefaultTheme(ThemeData theme) {
-    final isDark = theme.brightness == Brightness.dark;
-    final textTheme = isDark ? TextTheme.dark() : TextTheme.light();
-    final colorTheme = isDark ? ColorTheme.dark() : ColorTheme.light();
-    return fromColorAndTextTheme(
-      colorTheme,
-      textTheme,
-    );
-  }
-}
-
-enum TextThemeType {
-  light,
-  dark,
 }
 
 class TextTheme {
@@ -427,17 +451,17 @@ class TextTheme {
   });
 
   TextTheme copyWith({
-    TextThemeType type = TextThemeType.light,
+    Brightness brightness = Brightness.light,
-    TextStyle body,
+    TextStyle? body,
-    TextStyle title,
+    TextStyle? title,
-    TextStyle headlineBold,
+    TextStyle? headlineBold,
-    TextStyle headline,
+    TextStyle? headline,
-    TextStyle bodyBold,
+    TextStyle? bodyBold,
-    TextStyle footnoteBold,
+    TextStyle? footnoteBold,
-    TextStyle footnote,
+    TextStyle? footnote,
-    TextStyle captionBold,
+    TextStyle? captionBold,
   }) {
-    return type == TextThemeType.light
+    return brightness == Brightness.light
         ? TextTheme.light(
             body: body ?? this.body,
             title: title ?? this.title,
@@ -460,28 +484,21 @@ class TextTheme {
           );
   }
 
-  TextTheme merge(TextTheme other) {
+  TextTheme merge(TextTheme? other) {
     if (other == null) return this;
     return copyWith(
-      body: body?.merge(other.body) ?? other.body,
+      body: body.merge(other.body),
-      title: title?.merge(other.title) ?? other.title,
+      title: title.merge(other.title),
-      headlineBold:
+      headlineBold: headlineBold.merge(other.headlineBold),
-          headlineBold?.merge(other.headlineBold) ?? other.headlineBold,
+      headline: headline.merge(other.headline),
-      headline: headline?.merge(other.headline) ?? other.headline,
+      bodyBold: bodyBold.merge(other.bodyBold),
-      bodyBold: bodyBold?.merge(other.bodyBold) ?? other.bodyBold,
+      footnoteBold: footnoteBold.merge(other.footnoteBold),
-      footnoteBold:
+      footnote: footnote.merge(other.footnote),
-          footnoteBold?.merge(other.footnoteBold) ?? other.footnoteBold,
+      captionBold: captionBold.merge(other.captionBold),
-      footnote: footnote?.merge(other.footnote) ?? other.footnote,
-      captionBold: captionBold?.merge(other.captionBold) ?? other.captionBold,
     );
   }
 }
 
-enum ColorThemeType {
-  light,
-  dark,
-}
-
 class ColorTheme {
   final Color black;
   final Color grey;
@@ -502,6 +519,7 @@ class ColorTheme {
   final Color overlay;
   final Color overlayDark;
   final Gradient bgGradient;
+  final Brightness brightness;
 
   ColorTheme.light({
     this.black = const Color(0xff000000),
@@ -536,7 +554,7 @@ class ColorTheme {
         sigmaX: 0, sigmaY: 2, color: Color(0xff000000), alpha: 0.5, blur: 4.0),
     this.modalShadow = const Effect(
         sigmaX: 0, sigmaY: 0, color: Color(0xff000000), alpha: 1, blur: 8.0),
-  });
+  }) : brightness = Brightness.light;
 
   ColorTheme.dark({
     this.black = const Color(0xffffffff),
@@ -551,13 +569,32 @@ class ColorTheme {
     this.accentRed = const Color(0xffFF3742),
     this.accentGreen = const Color(0xff20E070),
     this.borderTop = const Effect(
-        sigmaX: 0, sigmaY: -1, color: Color(0xff141924), blur: 0.0),
+      sigmaX: 0,
+      sigmaY: -1,
+      color: Color(0xff141924),
+      blur: 0.0,
+    ),
     this.borderBottom = const Effect(
-        sigmaX: 0, sigmaY: 1, color: Color(0xff141924), blur: 0.0, alpha: 1.0),
+      sigmaX: 0,
+      sigmaY: 1,
+      color: Color(0xff141924),
+      blur: 0.0,
+      alpha: 1.0,
+    ),
     this.shadowIconButton = const Effect(
-        sigmaX: 0, sigmaY: 2, color: Color(0xff000000), alpha: 0.5, blur: 4.0),
+      sigmaX: 0,
+      sigmaY: 2,
+      color: Color(0xff000000),
+      alpha: 0.5,
+      blur: 4.0,
+    ),
     this.modalShadow = const Effect(
-        sigmaX: 0, sigmaY: 0, color: Color(0xff000000), alpha: 1, blur: 8.0),
+      sigmaX: 0,
+      sigmaY: 0,
+      color: Color(0xff000000),
+      alpha: 1,
+      blur: 8.0,
+    ),
     this.highlight = const Color(0xff302d22),
     this.overlay = const Color.fromRGBO(0, 0, 0, 0.4),
     this.overlayDark = const Color.fromRGBO(255, 255, 255, 0.6),
@@ -570,31 +607,31 @@ class ColorTheme {
       ],
       stops: [0, 1],
     ),
-  });
+  }) : brightness = Brightness.dark;
 
   ColorTheme copyWith({
-    ColorThemeType type = ColorThemeType.light,
+    Brightness brightness = Brightness.light,
-    Color black,
+    Color? black,
-    Color grey,
+    Color? grey,
-    Color greyGainsboro,
+    Color? greyGainsboro,
-    Color greyWhisper,
+    Color? greyWhisper,
-    Color whiteSmoke,
+    Color? whiteSmoke,
-    Color whiteSnow,
+    Color? whiteSnow,
-    Color white,
+    Color? white,
-    Color blueAlice,
+    Color? blueAlice,
-    Color accentBlue,
+    Color? accentBlue,
-    Color accentRed,
+    Color? accentRed,
-    Color accentGreen,
+    Color? accentGreen,
-    Effect borderTop,
+    Effect? borderTop,
-    Effect borderBottom,
+    Effect? borderBottom,
-    Effect shadowIconButton,
+    Effect? shadowIconButton,
-    Effect modalShadow,
+    Effect? modalShadow,
-    Color highlight,
+    Color? highlight,
-    Color overlay,
+    Color? overlay,
-    Color overlayDark,
+    Color? overlayDark,
-    Gradient bgGradient,
+    Gradient? bgGradient,
   }) {
-    return type == ColorThemeType.light
+    return brightness == Brightness.light
         ? ColorTheme.light(
             black: black ?? this.black,
             grey: grey ?? this.grey,
@@ -639,7 +676,7 @@ class ColorTheme {
           );
   }
 
-  ColorTheme merge(ColorTheme other) {
+  ColorTheme merge(ColorTheme? other) {
     if (other == null) return this;
     return copyWith(
       black: other.black,
@@ -671,65 +708,77 @@ class ChannelTheme {
   final ChannelHeaderTheme channelHeaderTheme;
 
   ChannelTheme({
-    this.channelHeaderTheme,
+    required this.channelHeaderTheme,
   });
 
   /// Creates a copy of [ChannelTheme] with specified attributes overridden.
   ChannelTheme copyWith({
-    ChannelHeaderTheme channelHeaderTheme,
+    ChannelHeaderTheme? channelHeaderTheme,
   }) =>
       ChannelTheme(
         channelHeaderTheme: channelHeaderTheme ?? this.channelHeaderTheme,
       );
 
-  ChannelTheme merge(ChannelTheme other) {
+  ChannelTheme merge(ChannelTheme? other) {
     if (other == null) return this;
     return copyWith(
-      channelHeaderTheme: channelHeaderTheme?.merge(other.channelHeaderTheme) ??
+      channelHeaderTheme: channelHeaderTheme.merge(other.channelHeaderTheme),
-          other.channelHeaderTheme,
     );
   }
 }
 
 class AvatarTheme {
-  final BoxConstraints constraints;
+  final BoxConstraints? _constraints;
-  final BorderRadius borderRadius;
+  final BorderRadius? _borderRadius;
+
+  BoxConstraints get constraints {
+    return _constraints ??
+        BoxConstraints.tightFor(
+          height: 32,
+          width: 32,
+        );
+  }
+
+  BorderRadius get borderRadius {
+    return _borderRadius ?? BorderRadius.circular(20);
+  }
 
   AvatarTheme({
-    this.constraints,
+    BoxConstraints? constraints,
-    this.borderRadius,
+    BorderRadius? borderRadius,
-  });
+  })  : _constraints = constraints,
+        _borderRadius = borderRadius;
 
   AvatarTheme copyWith({
-    BoxConstraints constraints,
+    BoxConstraints? constraints,
-    BorderRadius borderRadius,
+    BorderRadius? borderRadius,
   }) =>
       AvatarTheme(
-        constraints: constraints ?? this.constraints,
+        constraints: constraints ?? _constraints,
-        borderRadius: borderRadius ?? this.borderRadius,
+        borderRadius: borderRadius ?? _borderRadius,
       );
 
-  AvatarTheme merge(AvatarTheme other) {
+  AvatarTheme merge(AvatarTheme? other) {
     if (other == null) return this;
     return copyWith(
-      constraints: other.constraints,
+      constraints: other._constraints,
-      borderRadius: other.borderRadius,
+      borderRadius: other._borderRadius,
     );
   }
 }
 
 class MessageTheme {
-  final TextStyle messageText;
+  final TextStyle? messageText;
-  final TextStyle messageAuthor;
+  final TextStyle? messageAuthor;
-  final TextStyle messageLinks;
+  final TextStyle? messageLinks;
-  final TextStyle createdAt;
+  final TextStyle? createdAt;
-  final TextStyle replies;
+  final TextStyle? replies;
-  final Color messageBackgroundColor;
+  final Color? messageBackgroundColor;
-  final Color messageBorderColor;
+  final Color? messageBorderColor;
-  final Color reactionsBackgroundColor;
+  final Color? reactionsBackgroundColor;
-  final Color reactionsBorderColor;
+  final Color? reactionsBorderColor;
-  final Color reactionsMaskColor;
+  final Color? reactionsMaskColor;
-  final AvatarTheme avatarTheme;
+  final AvatarTheme? avatarTheme;
 
   const MessageTheme({
     this.replies,
@@ -746,17 +795,17 @@ class MessageTheme {
   });
 
   MessageTheme copyWith({
-    TextStyle messageText,
+    TextStyle? messageText,
-    TextStyle messageAuthor,
+    TextStyle? messageAuthor,
-    TextStyle messageLinks,
+    TextStyle? messageLinks,
-    TextStyle createdAt,
+    TextStyle? createdAt,
-    TextStyle replies,
+    TextStyle? replies,
-    Color messageBackgroundColor,
+    Color? messageBackgroundColor,
-    Color messageBorderColor,
+    Color? messageBorderColor,
-    AvatarTheme avatarTheme,
+    AvatarTheme? avatarTheme,
-    Color reactionsBackgroundColor,
+    Color? reactionsBackgroundColor,
-    Color reactionsBorderColor,
+    Color? reactionsBorderColor,
-    Color reactionsMaskColor,
+    Color? reactionsMaskColor,
   }) =>
       MessageTheme(
         messageText: messageText ?? this.messageText,
@@ -774,7 +823,7 @@ class MessageTheme {
         reactionsMaskColor: reactionsMaskColor ?? this.reactionsMaskColor,
       );
 
-  MessageTheme merge(MessageTheme other) {
+  MessageTheme merge(MessageTheme? other) {
     if (other == null) return this;
     return copyWith(
       messageText: messageText?.merge(other.messageText) ?? other.messageText,
@@ -795,12 +844,12 @@ class MessageTheme {
 }
 
 class ChannelPreviewTheme {
-  final TextStyle title;
+  final TextStyle? title;
-  final TextStyle subtitle;
+  final TextStyle? subtitle;
-  final TextStyle lastMessageAt;
+  final TextStyle? lastMessageAt;
-  final AvatarTheme avatarTheme;
+  final AvatarTheme? avatarTheme;
-  final Color unreadCounterColor;
+  final Color? unreadCounterColor;
-  final double indicatorIconSize;
+  final double? indicatorIconSize;
 
   const ChannelPreviewTheme({
     this.title,
@@ -812,12 +861,12 @@ class ChannelPreviewTheme {
   });
 
   ChannelPreviewTheme copyWith({
-    TextStyle title,
+    TextStyle? title,
-    TextStyle subtitle,
+    TextStyle? subtitle,
-    TextStyle lastMessageAt,
+    TextStyle? lastMessageAt,
-    AvatarTheme avatarTheme,
+    AvatarTheme? avatarTheme,
-    Color unreadCounterColor,
+    Color? unreadCounterColor,
-    double indicatorIconSize,
+    double? indicatorIconSize,
   }) =>
       ChannelPreviewTheme(
         title: title ?? this.title,
@@ -828,7 +877,7 @@ class ChannelPreviewTheme {
         indicatorIconSize: indicatorIconSize ?? this.indicatorIconSize,
       );
 
-  ChannelPreviewTheme merge(ChannelPreviewTheme other) {
+  ChannelPreviewTheme merge(ChannelPreviewTheme? other) {
     if (other == null) return this;
     return copyWith(
       title: title?.merge(other.title) ?? other.title,
@@ -842,10 +891,10 @@ class ChannelPreviewTheme {
 }
 
 class ChannelHeaderTheme {
-  final TextStyle title;
+  final TextStyle? title;
-  final TextStyle subtitle;
+  final TextStyle? subtitle;
-  final AvatarTheme avatarTheme;
+  final AvatarTheme? avatarTheme;
-  final Color color;
+  final Color? color;
 
   const ChannelHeaderTheme({
     this.title,
@@ -855,10 +904,10 @@ class ChannelHeaderTheme {
   });
 
   ChannelHeaderTheme copyWith({
-    TextStyle title,
+    TextStyle? title,
-    TextStyle subtitle,
+    TextStyle? subtitle,
-    AvatarTheme avatarTheme,
+    AvatarTheme? avatarTheme,
-    Color color,
+    Color? color,
   }) =>
       ChannelHeaderTheme(
         title: title ?? this.title,
@@ -867,7 +916,7 @@ class ChannelHeaderTheme {
         color: color ?? this.color,
       );
 
-  ChannelHeaderTheme merge(ChannelHeaderTheme other) {
+  ChannelHeaderTheme merge(ChannelHeaderTheme? other) {
     if (other == null) return this;
     return copyWith(
       title: title?.merge(other.title) ?? other.title,
@@ -881,13 +930,13 @@ class ChannelHeaderTheme {
 /// Theme dedicated to the [ChannelListHeader]
 class ChannelListHeaderTheme {
   /// Style of the title text
-  final TextStyle title;
+  final TextStyle? title;
 
   /// Theme dedicated to the userAvatar
-  final AvatarTheme avatarTheme;
+  final AvatarTheme? avatarTheme;
 
   /// Background color of the appbar
-  final Color color;
+  final Color? color;
 
   /// Returns a new [ChannelListHeaderTheme]
   const ChannelListHeaderTheme({
@@ -898,9 +947,9 @@ class ChannelListHeaderTheme {
 
   /// Returns a new [ChannelListHeaderTheme] replacing some of its properties
   ChannelListHeaderTheme copyWith({
-    TextStyle title,
+    TextStyle? title,
-    AvatarTheme avatarTheme,
+    AvatarTheme? avatarTheme,
-    Color color,
+    Color? color,
   }) =>
       ChannelListHeaderTheme(
         title: title ?? this.title,
@@ -909,7 +958,7 @@ class ChannelListHeaderTheme {
       );
 
   /// Merges [this] [ChannelListHeaderTheme] with the [other]
-  ChannelListHeaderTheme merge(ChannelListHeaderTheme other) {
+  ChannelListHeaderTheme merge(ChannelListHeaderTheme? other) {
     if (other == null) return this;
     return copyWith(
       title: title?.merge(other.title) ?? other.title,
@@ -922,40 +971,40 @@ class ChannelListHeaderTheme {
 /// Defines the theme dedicated to the [MessageInput] widget
 class MessageInputTheme {
   /// Duration of the [MessageInput] send button animation
-  final Duration sendAnimationDuration;
+  final Duration? sendAnimationDuration;
 
   /// Background color of [MessageInput] send button
-  final Color sendButtonColor;
+  final Color? sendButtonColor;
 
   /// Background color of [MessageInput] action buttons
-  final Color actionButtonColor;
+  final Color? actionButtonColor;
 
   /// Background color of [MessageInput] send button
-  final Color sendButtonIdleColor;
+  final Color? sendButtonIdleColor;
 
   /// Background color of [MessageInput] action buttons
-  final Color actionButtonIdleColor;
+  final Color? actionButtonIdleColor;
 
   /// Background color of [MessageInput] expand button
-  final Color expandButtonColor;
+  final Color? expandButtonColor;
 
   /// Background color of [MessageInput]
-  final Color inputBackground;
+  final Color? inputBackground;
 
   /// TextStyle of [MessageInput]
-  final TextStyle inputTextStyle;
+  final TextStyle? inputTextStyle;
 
   /// InputDecoration of [MessageInput]
-  final InputDecoration inputDecoration;
+  final InputDecoration? inputDecoration;
 
   /// Border gradient when the [MessageInput] is not focused
-  final Gradient idleBorderGradient;
+  final Gradient? idleBorderGradient;
 
   /// Border gradient when the [MessageInput] is focused
-  final Gradient activeBorderGradient;
+  final Gradient? activeBorderGradient;
 
   /// Border radius of [MessageInput]
-  final BorderRadius borderRadius;
+  final BorderRadius? borderRadius;
 
   /// Returns a new [MessageInputTheme]
   const MessageInputTheme({
@@ -975,18 +1024,18 @@ class MessageInputTheme {
 
   /// Returns a new [MessageInputTheme] replacing some of its properties
   MessageInputTheme copyWith({
-    Duration sendAnimationDuration,
+    Duration? sendAnimationDuration,
-    Color inputBackground,
+    Color? inputBackground,
-    Color actionButtonColor,
+    Color? actionButtonColor,
-    Color sendButtonColor,
+    Color? sendButtonColor,
-    Color actionButtonIdleColor,
+    Color? actionButtonIdleColor,
-    Color sendButtonIdleColor,
+    Color? sendButtonIdleColor,
-    Color expandButtonColor,
+    Color? expandButtonColor,
-    TextStyle inputTextStyle,
+    TextStyle? inputTextStyle,
-    InputDecoration inputDecoration,
+    InputDecoration? inputDecoration,
-    Gradient activeBorderGradient,
+    Gradient? activeBorderGradient,
-    Gradient idleBorderGradient,
+    Gradient? idleBorderGradient,
-    BorderRadius borderRadius,
+    BorderRadius? borderRadius,
   }) =>
       MessageInputTheme(
         sendAnimationDuration:
@@ -1006,7 +1055,7 @@ class MessageInputTheme {
       );
 
   /// Merges [this] [MessageInputTheme] with the [other]
-  MessageInputTheme merge(MessageInputTheme other) {
+  MessageInputTheme merge(MessageInputTheme? other) {
     if (other == null) return this;
     return copyWith(
       sendAnimationDuration: other.sendAnimationDuration,
@@ -1027,11 +1076,11 @@ class MessageInputTheme {
 }
 
 class Effect {
-  final double sigmaX;
+  final double? sigmaX;
-  final double sigmaY;
+  final double? sigmaY;
-  final Color color;
+  final Color? color;
-  final double alpha;
+  final double? alpha;
-  final double blur;
+  final double? blur;
 
   const Effect({
     this.sigmaX,
@@ -1042,17 +1091,17 @@ class Effect {
   });
 
   Effect copyWith({
-    double sigmaX,
+    double? sigmaX,
-    double sigmaY,
+    double? sigmaY,
-    Color color,
+    Color? color,
-    double alpha,
+    double? alpha,
-    double blur,
+    double? blur,
   }) =>
       Effect(
         sigmaX: sigmaX ?? this.sigmaX,
         sigmaY: sigmaY ?? this.sigmaY,
         color: color ?? this.color,
-        alpha: color ?? this.alpha,
+        alpha: color as double? ?? this.alpha,
         blur: blur ?? this.blur,
       );
 }

packages/stream_chat_flutter/lib/src/stream_neumorphic_button.dart

@@ -5,8 +5,8 @@ class StreamNeumorphicButton extends StatelessWidget {
   final Color backgroundColor;
 
   const StreamNeumorphicButton({
-    Key key,
+    Key? key,
-    @required this.child,
+    required this.child,
     this.backgroundColor = Colors.white,
   }) : super(key: key);
 
@@ -21,7 +21,7 @@ class StreamNeumorphicButton extends StatelessWidget {
         shape: BoxShape.circle,
         boxShadow: [
           BoxShadow(
-            color: Colors.grey[700],
+            color: Colors.grey.shade700,
             offset: Offset(0, 1.0),
             blurRadius: 0.5,
             spreadRadius: 0,

packages/stream_chat_flutter/lib/src/stream_svg_icon.dart

@@ -3,10 +3,10 @@ import 'package:flutter/material.dart';
 import 'package:flutter_svg/flutter_svg.dart';
 
 class StreamSvgIcon extends StatelessWidget {
-  final String assetName;
+  final String? assetName;
-  final double width;
+  final double? width;
-  final double height;
+  final double? height;
-  final Color color;
+  final Color? color;
 
   const StreamSvgIcon({
     this.assetName,
@@ -30,8 +30,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.settings({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'settings.svg',
@@ -42,8 +42,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.down({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_down.svg',
@@ -54,8 +54,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.attach({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_attach.svg',
@@ -66,8 +66,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.smile({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_smile.svg',
@@ -78,8 +78,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.mentions({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'mentions.svg',
@@ -90,8 +90,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.record({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_record.svg',
@@ -102,8 +102,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.camera({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_camera.svg',
@@ -114,8 +114,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.files({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'files.svg',
@@ -126,8 +126,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.pictures({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'pictures.svg',
@@ -138,8 +138,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.left({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_left.svg',
@@ -150,8 +150,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.user({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_user.svg',
@@ -162,8 +162,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.userAdd({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_User_add.svg',
@@ -174,8 +174,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.check({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_check.svg',
@@ -186,8 +186,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.checkAll({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_check_all.svg',
@@ -198,8 +198,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.checkSend({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_check_send.svg',
@@ -210,8 +210,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.penWrite({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_pen-write.svg',
@@ -222,8 +222,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.contacts({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_contacts.svg',
@@ -234,8 +234,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.close({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_close.svg',
@@ -246,8 +246,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.search({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_search.svg',
@@ -258,8 +258,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.right({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_right.svg',
@@ -270,8 +270,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.mute({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_mute.svg',
@@ -282,8 +282,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.userRemove({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_User_deselect.svg',
@@ -294,8 +294,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.lightning({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_lightning-command runner.svg',
@@ -306,8 +306,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.emptyCircleLeft({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_empty_circle_left.svg',
@@ -318,8 +318,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.message({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_message.svg',
@@ -330,8 +330,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.thread({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_Thread_Reply.svg',
@@ -342,8 +342,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.reply({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_curve_line_left_up_big.svg',
@@ -354,8 +354,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.edit({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_edit.svg',
@@ -366,8 +366,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.download({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_download.svg',
@@ -378,8 +378,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.cloudDownload({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_cloud_download.svg',
@@ -390,8 +390,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.copy({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_copy.svg',
@@ -402,8 +402,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.delete({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_delete.svg',
@@ -414,8 +414,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.eye({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_eye-off.svg',
@@ -426,8 +426,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.arrowRight({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_arrow_right.svg',
@@ -438,8 +438,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.closeSmall({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_close_sml.svg',
@@ -450,8 +450,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconCurveLineLeftUp({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_curve_line_left_up.svg',
@@ -462,8 +462,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconMoon({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'icon_moon.svg',
@@ -474,8 +474,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconShare({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'icon_SHARE.svg',
@@ -486,8 +486,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconGrid({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_grid.svg',
@@ -498,8 +498,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconSendMessage({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_send_message.svg',
@@ -510,8 +510,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconMenuPoint({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_menu_point_v.svg',
@@ -522,8 +522,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconSave({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_save.svg',
@@ -534,8 +534,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.shareArrow({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'share_arrow.svg',
@@ -546,8 +546,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetype7z({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_7z.svg',
@@ -558,8 +558,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeCsv({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_CSV.svg',
@@ -570,8 +570,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeDoc({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_DOC.svg',
@@ -582,8 +582,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeDocx({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_DOCX.svg',
@@ -594,8 +594,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeGeneric({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_Generic.svg',
@@ -606,8 +606,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeHtml({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_html.svg',
@@ -618,8 +618,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeMd({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_MD.svg',
@@ -630,8 +630,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeOdt({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_ODT.svg',
@@ -642,8 +642,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypePdf({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_PDF.svg',
@@ -654,8 +654,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypePpt({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_PPT.svg',
@@ -666,8 +666,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypePptx({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_PPTX.svg',
@@ -678,8 +678,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeRar({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_RAR.svg',
@@ -690,8 +690,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeRtf({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_RTF.svg',
@@ -702,8 +702,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeTar({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_TAR.svg',
@@ -714,8 +714,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeTxt({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_TXT.svg',
@@ -726,8 +726,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeXls({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_XLS.svg',
@@ -738,8 +738,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeXlsx({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_XLSX.svg',
@@ -750,8 +750,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.filetypeZip({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'filetype_ZIP.svg',
@@ -762,8 +762,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconGroup({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_group.svg',
@@ -774,8 +774,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconNotification({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_notification.svg',
@@ -786,8 +786,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconUserDelete({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_user_delete.svg',
@@ -798,8 +798,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.error({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_error.svg',
@@ -810,8 +810,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.circleUp({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_circle_up.svg',
@@ -822,8 +822,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconUserSettings({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'Icon_user_settings.svg',
@@ -834,8 +834,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.giphyIcon({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'giphy_icon.svg',
@@ -846,8 +846,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.imgur({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'imgur.svg',
@@ -858,8 +858,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.volumeUp({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'volume-up.svg',
@@ -870,8 +870,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.flag({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'flag.svg',
@@ -882,8 +882,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.iconFlag({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'icon_flag.svg',
@@ -894,8 +894,8 @@ class StreamSvgIcon extends StatelessWidget {
   }
 
   factory StreamSvgIcon.retry({
-    double size,
+    double? size,
-    Color color,
+    Color? color,
   }) {
     return StreamSvgIcon(
       assetName: 'icon_retry.svg',

packages/stream_chat_flutter/lib/src/swipeable.dart

@@ -8,15 +8,15 @@ import 'stream_chat_theme.dart';
 class Swipeable extends StatefulWidget {
   final Widget child;
   final Widget backgroundIcon;
-  final VoidCallback onSwipeStart;
+  final VoidCallback? onSwipeStart;
-  final VoidCallback onSwipeCancel;
+  final VoidCallback? onSwipeCancel;
-  final VoidCallback onSwipeEnd;
+  final VoidCallback? onSwipeEnd;
   final double threshold;
 
   ///
   const Swipeable({
-    @required this.child,
+    required this.child,
-    @required this.backgroundIcon,
+    required this.backgroundIcon,
     this.onSwipeStart,
     this.onSwipeCancel,
     this.onSwipeEnd,
@@ -29,11 +29,11 @@ class Swipeable extends StatefulWidget {
 
 class _SwipeableState extends State<Swipeable> with TickerProviderStateMixin {
   double _dragExtent = 0.0;
-  AnimationController _moveController;
+  late AnimationController _moveController;
-  AnimationController _iconMoveController;
+  late AnimationController _iconMoveController;
-  Animation<Offset> _moveAnimation;
+  late Animation<Offset> _moveAnimation;
-  Animation<Offset> _iconTransitionAnimation;
+  late Animation<Offset> _iconTransitionAnimation;
-  Animation<double> _iconFadeAnimation;
+  late Animation<double> _iconFadeAnimation;
   bool _pastThreshold = false;
 
   final _animationDuration = const Duration(milliseconds: 200);
@@ -67,18 +67,18 @@ class _SwipeableState extends State<Swipeable> with TickerProviderStateMixin {
 
   void _handleDragStart(DragStartDetails details) {
     if (widget.onSwipeStart != null) {
-      widget.onSwipeStart();
+      widget.onSwipeStart!();
     }
   }
 
   void _handleDragUpdate(DragUpdateDetails details) {
-    final delta = details.primaryDelta;
+    final delta = details.primaryDelta!;
     _dragExtent += delta;
 
     if (_dragExtent.isNegative) return;
 
     var movePastThresholdPixels = widget.threshold;
-    var newPos = _dragExtent.abs() / context.size.width;
+    var newPos = _dragExtent.abs() / context.size!.width;
 
     if (_dragExtent.abs() > movePastThresholdPixels) {
       // how many "thresholds" past the threshold we are. 1 = the threshold 2
@@ -90,7 +90,7 @@ class _SwipeableState extends State<Swipeable> with TickerProviderStateMixin {
       var reducedThreshold = math.pow(n, 0.3);
 
       var adjustedPixelPos = movePastThresholdPixels * reducedThreshold;
-      newPos = adjustedPixelPos / context.size.width;
+      newPos = adjustedPixelPos / context.size!.width;
 
       if (_dragExtent > 0 && !_pastThreshold) {
         _iconMoveController.value = 1;
@@ -100,7 +100,7 @@ class _SwipeableState extends State<Swipeable> with TickerProviderStateMixin {
       // Send a cancel event if the user has swiped back underneath the
       // threshold
       if (_pastThreshold && widget.onSwipeCancel != null) {
-        widget.onSwipeCancel();
+        widget.onSwipeCancel!();
       }
       _pastThreshold = false;
     }
@@ -115,7 +115,7 @@ class _SwipeableState extends State<Swipeable> with TickerProviderStateMixin {
     _iconMoveController.animateTo(0.0, duration: _animationDuration);
     _dragExtent = 0.0;
     if (_pastThreshold && widget.onSwipeEnd != null) {
-      widget.onSwipeEnd();
+      widget.onSwipeEnd!();
     }
   }
 

packages/stream_chat_flutter/lib/src/system_message.dart

@@ -7,11 +7,11 @@ class SystemMessage extends StatelessWidget {
   final Message message;
 
   /// The function called when tapping on the message when the message is not failed
-  final void Function(Message) onMessageTap;
+  final void Function(Message)? onMessageTap;
 
   const SystemMessage({
-    Key key,
+    Key? key,
-    @required this.message,
+    required this.message,
     this.onMessageTap,
   }) : super(key: key);
 
@@ -22,11 +22,11 @@ class SystemMessage extends StatelessWidget {
       behavior: HitTestBehavior.opaque,
       onTap: () {
         if (onMessageTap != null) {
-          onMessageTap(message);
+          onMessageTap!(message);
         }
       },
       child: Text(
-        message.text,
+        message.text!,
         textAlign: TextAlign.center,
         softWrap: true,
         style: theme.textTheme.captionBold.copyWith(

packages/stream_chat_flutter/lib/src/thread_header.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
-import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
+import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 import 'back_button.dart';
 import 'channel_name.dart';
@@ -61,30 +61,30 @@ class ThreadHeader extends StatelessWidget implements PreferredSizeWidget {
 
   /// Callback to call when pressing the back button.
   /// By default it calls [Navigator.pop]
-  final VoidCallback onBackPressed;
+  final VoidCallback? onBackPressed;
 
   /// Callback to call when the title is tapped.
-  final VoidCallback onTitleTap;
+  final VoidCallback? onTitleTap;
 
   /// The message parent of this thread
   final Message parent;
 
   /// Title widget
-  final Widget title;
+  final Widget? title;
 
   /// Subtitle widget
-  final Widget subtitle;
+  final Widget? subtitle;
 
   /// Leading widget
-  final Widget leading;
+  final Widget? leading;
 
   /// AppBar actions
-  final List<Widget> actions;
+  final List<Widget>? actions;
 
   /// Instantiate a new ThreadHeader
   ThreadHeader({
-    Key key,
+    Key? key,
-    @required this.parent,
+    required this.parent,
     this.showBackButton = true,
     this.onBackPressed,
     this.title,

packages/stream_chat_flutter/lib/src/typing_indicator.dart

@@ -6,7 +6,7 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 class TypingIndicator extends StatelessWidget {
   /// Instantiate a new TypingIndicator
   const TypingIndicator({
-    Key key,
+    Key? key,
     this.channel,
     this.alternativeWidget,
     this.style,
@@ -15,13 +15,13 @@ class TypingIndicator extends StatelessWidget {
   }) : super(key: key);
 
   /// Style of the text widget
-  final TextStyle style;
+  final TextStyle? style;
 
   /// List of typing users
-  final Channel channel;
+  final Channel? channel;
 
   /// Widget built when no typings is happening
-  final Widget alternativeWidget;
+  final Widget? alternativeWidget;
 
   /// The padding of this widget
   final EdgeInsets padding;
@@ -31,7 +31,7 @@ class TypingIndicator extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final channelState =
-        channel?.state ?? StreamChannel.of(context).channel.state;
+        channel?.state ?? StreamChannel.of(context).channel.state!;
     return StreamBuilder<List<User>>(
       initialData: channelState.typingEvents,
       stream: channelState.typingEventsStream,
@@ -53,7 +53,7 @@ class TypingIndicator extends StatelessWidget {
                           height: 4,
                         ),
                         Text(
-                          '  ${snapshot.data[0].name}${snapshot.data.length == 1 ? '' : ' and ${snapshot.data.length - 1} more'} ${snapshot.data.length == 1 ? 'is' : 'are'} typing',
+                          '  ${snapshot.data![0].name}${snapshot.data!.length == 1 ? '' : ' and ${snapshot.data!.length - 1} more'} ${snapshot.data!.length == 1 ? 'is' : 'are'} typing',
                           maxLines: 1,
                           style: style,
                         ),

packages/stream_chat_flutter/lib/src/unread_indicator.dart

@@ -4,23 +4,23 @@ import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 class UnreadIndicator extends StatelessWidget {
   const UnreadIndicator({
-    Key key,
+    Key? key,
     this.cid,
   }) : super(key: key);
 
   /// Channel cid used to retrieve unread count
-  final String cid;
+  final String? cid;
 
   @override
   Widget build(BuildContext context) {
     final client = StreamChat.of(context).client;
     return IgnorePointer(
-      child: StreamBuilder<int>(
+      child: StreamBuilder<int?>(
         stream: cid != null
-            ? client.state.channels[cid].state.unreadCountStream
+            ? client.state.channels[cid]?.state?.unreadCountStream
             : client.state.totalUnreadCountStream,
         initialData: cid != null
-            ? client.state.channels[cid].state.unreadCount
+            ? client.state.channels[cid]?.state?.unreadCount
             : client.state.totalUnreadCount,
         builder: (context, snapshot) {
           if (!snapshot.hasData || snapshot.data == 0) {
@@ -40,7 +40,7 @@ class UnreadIndicator extends StatelessWidget {
               ),
               child: Center(
                 child: Text(
-                  '${snapshot.data > 99 ? '99+' : snapshot.data}',
+                  '${snapshot.data! > 99 ? '99+' : snapshot.data}',
                   style: TextStyle(
                     fontSize: 11,
                     color: Colors.white,

packages/stream_chat_flutter/lib/src/upload_progress_indicator.dart

@@ -5,20 +5,27 @@ import 'stream_chat_theme.dart';
 class UploadProgressIndicator extends StatelessWidget {
   final int uploaded;
   final int total;
-  final Color progressIndicatorColor;
+  late final Color progressIndicatorColor;
   final EdgeInsetsGeometry padding;
   final bool showBackground;
-  final TextStyle textStyle;
+  final TextStyle? textStyle;
 
-  const UploadProgressIndicator({
+  UploadProgressIndicator({
-    Key key,
+    Key? key,
-    @required this.uploaded,
+    required this.uploaded,
-    @required this.total,
+    required this.total,
-    this.progressIndicatorColor = const Color(0xffb2b2b2),
+    Color? progressIndicatorColor,
-    this.padding = const EdgeInsets.only(top: 5, bottom: 5, right: 11, left: 5),
+    this.padding = const EdgeInsets.only(
+      top: 5,
+      bottom: 5,
+      right: 11,
+      left: 5,
+    ),
     this.showBackground = true,
     this.textStyle,
-  }) : super(key: key);
+  })  : progressIndicatorColor =
+            progressIndicatorColor ?? const Color(0xffb2b2b2),
+        super(key: key);
 
   @override
   Widget build(BuildContext context) {

packages/stream_chat_flutter/lib/src/url_attachment.dart

@@ -9,9 +9,9 @@ class UrlAttachment extends StatelessWidget {
   final EdgeInsets textPadding;
 
   UrlAttachment({
-    @required this.urlAttachment,
+    required this.urlAttachment,
-    @required this.hostDisplayName,
+    required this.hostDisplayName,
-    @required this.textPadding,
+    required this.textPadding,
   });
 
   @override
@@ -19,7 +19,7 @@ class UrlAttachment extends StatelessWidget {
     return GestureDetector(
       onTap: () => launchURL(
         context,
-        urlAttachment.ogScrapeUrl,
+        urlAttachment.ogScrapeUrl!,
       ),
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -35,7 +35,7 @@ class UrlAttachment extends StatelessWidget {
                 children: [
                   CachedNetworkImage(
                     width: double.infinity,
-                    imageUrl: urlAttachment.imageUrl,
+                    imageUrl: urlAttachment.imageUrl!,
                     fit: BoxFit.cover,
                   ),
                   Positioned(
@@ -78,7 +78,7 @@ class UrlAttachment extends StatelessWidget {
               children: [
                 if (urlAttachment.title != null)
                   Text(
-                    urlAttachment.title.trim(),
+                    urlAttachment.title!.trim(),
                     maxLines: 1,
                     overflow: TextOverflow.ellipsis,
                     style: StreamChatTheme.of(context)
@@ -88,7 +88,7 @@ class UrlAttachment extends StatelessWidget {
                   ),
                 if (urlAttachment.text != null)
                   Text(
-                    urlAttachment.text,
+                    urlAttachment.text!,
                     style: StreamChatTheme.of(context)
                         .textTheme
                         .body

packages/stream_chat_flutter/lib/src/user_avatar.dart

@@ -6,8 +6,8 @@ import '../stream_chat_flutter.dart';
 
 class UserAvatar extends StatelessWidget {
   const UserAvatar({
-    Key key,
+    Key? key,
-    @required this.user,
+    required this.user,
     this.constraints,
     this.onlineIndicatorConstraints,
     this.onTap,
@@ -22,19 +22,19 @@ class UserAvatar extends StatelessWidget {
 
   final User user;
   final Alignment onlineIndicatorAlignment;
-  final BoxConstraints constraints;
+  final BoxConstraints? constraints;
-  final BorderRadius borderRadius;
+  final BorderRadius? borderRadius;
-  final BoxConstraints onlineIndicatorConstraints;
+  final BoxConstraints? onlineIndicatorConstraints;
-  final void Function(User) onTap;
+  final void Function(User)? onTap;
-  final void Function(User) onLongPress;
+  final void Function(User)? onLongPress;
   final bool showOnlineStatus;
   final bool selected;
-  final Color selectionColor;
+  final Color? selectionColor;
   final double selectionThickness;
 
   @override
   Widget build(BuildContext context) {
-    final hasImage = user.extraData?.containsKey('image') == true &&
+    final hasImage = user.extraData.containsKey('image') &&
         user.extraData['image'] != null &&
         user.extraData['image'] != '';
     final streamChatTheme = StreamChatTheme.of(context);
@@ -44,17 +44,17 @@ class UserAvatar extends StatelessWidget {
       child: ClipRRect(
         clipBehavior: Clip.antiAlias,
         borderRadius: borderRadius ??
-            streamChatTheme.ownMessageTheme.avatarTheme.borderRadius,
+            streamChatTheme.ownMessageTheme.avatarTheme?.borderRadius,
         child: Container(
           constraints: constraints ??
-              streamChatTheme.ownMessageTheme.avatarTheme.constraints,
+              streamChatTheme.ownMessageTheme.avatarTheme?.constraints,
           decoration: BoxDecoration(
             color: streamChatTheme.colorTheme.accentBlue,
           ),
           child: hasImage
               ? CachedNetworkImage(
                   filterQuality: FilterQuality.high,
-                  imageUrl: user.extraData['image'],
+                  imageUrl: user.extraData['image'] as String,
                   errorWidget: (_, __, ___) {
                     return streamChatTheme.defaultUserImage(context, user);
                   },
@@ -68,11 +68,12 @@ class UserAvatar extends StatelessWidget {
     if (selected) {
       avatar = ClipRRect(
         borderRadius: (borderRadius ??
-                streamChatTheme.ownMessageTheme.avatarTheme.borderRadius) +
+                streamChatTheme.ownMessageTheme.avatarTheme?.borderRadius ??
+                BorderRadius.zero) +
             BorderRadius.circular(selectionThickness),
         child: Container(
           constraints: constraints ??
-              streamChatTheme.ownMessageTheme.avatarTheme.constraints,
+              streamChatTheme.ownMessageTheme.avatarTheme?.constraints,
           color: selectionColor ??
               StreamChatTheme.of(context).colorTheme.accentBlue,
           child: Padding(
@@ -83,12 +84,12 @@ class UserAvatar extends StatelessWidget {
       );
     }
     return GestureDetector(
-      onTap: onTap != null ? () => onTap(user) : null,
+      onTap: onTap != null ? () => onTap!(user) : null,
-      onLongPress: onLongPress != null ? () => onLongPress(user) : null,
+      onLongPress: onLongPress != null ? () => onLongPress!(user) : null,
       child: Stack(
         children: <Widget>[
           avatar,
-          if (showOnlineStatus && user.online == true)
+          if (showOnlineStatus && user.online)
             Positioned.fill(
               child: Align(
                 alignment: onlineIndicatorAlignment,

packages/stream_chat_flutter/lib/src/user_item.dart

@@ -1,9 +1,9 @@
 import 'package:flutter/material.dart';
 import 'package:jiffy/jiffy.dart';
-import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'package:stream_chat_flutter/src/stream_svg_icon.dart';
 import 'package:stream_chat_flutter/src/user_list_view.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
+import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 import 'stream_chat_theme.dart';
 
@@ -19,8 +19,8 @@ import 'stream_chat_theme.dart';
 class UserItem extends StatelessWidget {
   /// Instantiate a new UserItem
   const UserItem({
-    Key key,
+    Key? key,
-    @required this.user,
+    required this.user,
     this.onTap,
     this.onLongPress,
     this.onImageTap,
@@ -29,16 +29,16 @@ class UserItem extends StatelessWidget {
   }) : super(key: key);
 
   /// Function called when tapping this widget
-  final void Function(User) onTap;
+  final void Function(User)? onTap;
 
   /// Function called when long pressing this widget
-  final void Function(User) onLongPress;
+  final void Function(User)? onLongPress;
 
   /// User displayed
   final User user;
 
   /// The function called when the image is tapped
-  final void Function(User) onImageTap;
+  final void Function(User)? onImageTap;
 
   /// If true the [UserItem] will show a trailing checkmark
   final bool selected;
@@ -51,12 +51,12 @@ class UserItem extends StatelessWidget {
     return ListTile(
       onTap: () {
         if (onTap != null) {
-          onTap(user);
+          onTap!(user);
         }
       },
       onLongPress: () {
         if (onLongPress != null) {
-          onLongPress(user);
+          onLongPress!(user);
         }
       },
       leading: UserAvatar(
@@ -64,7 +64,7 @@ class UserItem extends StatelessWidget {
         showOnlineStatus: true,
         onTap: (user) {
           if (onImageTap != null) {
-            onImageTap(user);
+            onImageTap!(user);
           }
         },
         constraints: BoxConstraints.tightFor(

packages/stream_chat_flutter/lib/src/user_list_view.dart

@@ -5,7 +5,7 @@ import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'user_item.dart';
 
 /// Callback called when tapping on a user
-typedef UserTapCallback = void Function(User, Widget);
+typedef UserTapCallback = void Function(User, Widget?);
 
 /// Builder used to create a custom [ListUserItem] from a [User]
 typedef UserItemBuilder = Widget Function(BuildContext, User, bool);
@@ -44,7 +44,7 @@ typedef UserItemBuilder = Widget Function(BuildContext, User, bool);
 class UserListView extends StatefulWidget {
   /// Instantiate a new UserListView
   const UserListView({
-    Key key,
+    Key? key,
     this.filter,
     this.options,
     this.sort,
@@ -72,51 +72,51 @@ class UserListView extends StatefulWidget {
   /// The query filters to use.
   /// You can query on any of the custom fields you've defined on the [Channel].
   /// You can also filter other built-in channel fields.
-  final Filter filter;
+  final Filter? filter;
 
   /// Query channels options.
   ///
   /// state: if true returns the Channel state
   /// watch: if true listen to changes to this Channel in real time.
-  final Map<String, dynamic> options;
+  final Map<String, dynamic>? options;
 
   /// The sorting used for the channels matching the filters.
   /// Sorting is based on field and direction, multiple sorting options can be provided.
   /// You can sort based on last_updated, last_message_at, updated_at, created_at or member_count.
   /// Direction can be ascending or descending.
-  final List<SortOption> sort;
+  final List<SortOption>? sort;
 
   /// Pagination parameters
   /// limit: the number of users to return (max is 30)
   /// offset: the offset (max is 1000)
   /// message_limit: how many messages should be included to each channel
-  final PaginationParams pagination;
+  final PaginationParams? pagination;
 
   /// Function called when tapping on a channel
   /// By default it calls [Navigator.push] building a [MaterialPageRoute]
   /// with the widget [userWidget] as child.
-  final UserTapCallback onUserTap;
+  final UserTapCallback? onUserTap;
 
   /// Function called when long pressing on a channel
-  final Function(User) onUserLongPress;
+  final Function(User)? onUserLongPress;
 
   /// Widget used when opening a channel
-  final Widget userWidget;
+  final Widget? userWidget;
 
   /// Builder used to create a custom user preview
-  final UserItemBuilder userItemBuilder;
+  final UserItemBuilder? userItemBuilder;
 
   /// Builder used to create a custom item separator
-  final Function(BuildContext, int) separatorBuilder;
+  final Function(BuildContext, int)? separatorBuilder;
 
   /// The function called when the image is tapped
-  final Function(User) onImageTap;
+  final Function(User)? onImageTap;
 
   /// Set it to false to disable the pull-to-refresh widget
   final bool pullToRefresh;
 
   /// Sets a blue trailing checkMark in [ListUserItem] for all the [selectedUsers]
-  final Set<User> selectedUsers;
+  final Set<User>? selectedUsers;
 
   /// Set it to true to group users by their first character
   ///
@@ -127,16 +127,17 @@ class UserListView extends StatefulWidget {
   final int crossAxisCount;
 
   /// The builder that will be used in case of error
-  final Widget Function(Error error) errorBuilder;
+  final Widget Function(Error error)? errorBuilder;
 
   /// The builder that will be used to build the list
-  final Widget Function(BuildContext context, List<ListItem> users) listBuilder;
+  final Widget Function(BuildContext context, List<ListItem> users)?
+      listBuilder;
 
   /// The builder that will be used for loading
-  final WidgetBuilder loadingBuilder;
+  final WidgetBuilder? loadingBuilder;
 
   /// The builder used when the channel list is empty.
-  final WidgetBuilder emptyBuilder;
+  final WidgetBuilder? emptyBuilder;
 
   @override
   _UserListViewState createState() => _UserListViewState();
@@ -151,9 +152,9 @@ class _UserListViewState extends State<UserListView>
   @override
   Widget build(BuildContext context) {
     var child = UserListCore(
-      errorBuilder: widget.errorBuilder ??
+      errorBuilder: widget.errorBuilder as Widget Function(Object)? ??
           (err) {
-            return _buildError(err);
+            return _buildError(err as Error);
           },
       emptyBuilder: widget.emptyBuilder ??
           (context) {
@@ -193,7 +194,7 @@ class _UserListViewState extends State<UserListView>
       return child;
     } else {
       return RefreshIndicator(
-        onRefresh: () => _userListController.loadData(),
+        onRefresh: () => _userListController.loadData!(),
         child: child,
       );
     }
@@ -241,7 +242,7 @@ class _UserListViewState extends State<UserListView>
             child: Text(message),
           ),
           TextButton(
-            onPressed: () => _userListController.loadData(),
+            onPressed: () => _userListController.loadData!(),
             child: Text('Retry'),
           ),
         ],
@@ -276,7 +277,7 @@ class _UserListViewState extends State<UserListView>
             itemCount: items.isNotEmpty ? items.length + 1 : items.length,
             separatorBuilder: (_, index) {
               if (widget.separatorBuilder != null) {
-                return widget.separatorBuilder(context, index);
+                return widget.separatorBuilder!(context, index);
               }
               return _separatorBuilder(context, index);
             },
@@ -296,7 +297,7 @@ class _UserListViewState extends State<UserListView>
           );
 
     return LazyLoadScrollView(
-      onEndOfPage: () => _userListController.paginateData(),
+      onEndOfPage: () => _userListController.paginateData!(),
       child: child,
     );
   }
@@ -329,10 +330,10 @@ class _UserListViewState extends State<UserListView>
           return Container(
             key: ValueKey<String>('USER-${user.id}'),
             child: widget.userItemBuilder != null
-                ? widget.userItemBuilder(context, user, selected)
+                ? widget.userItemBuilder!(context, user, selected)
                 : UserItem(
                     user: user,
-                    onTap: (user) => widget.onUserTap(user, widget.userWidget),
+                    onTap: (user) => widget.onUserTap!(user, widget.userWidget),
                     onLongPress: widget.onUserLongPress,
                     onImageTap: widget.onImageTap,
                     selected: selected,
@@ -356,7 +357,7 @@ class _UserListViewState extends State<UserListView>
           return Container(
             key: ValueKey<String>('USER-${user.id}'),
             child: widget.userItemBuilder != null
-                ? widget.userItemBuilder(context, user, selected)
+                ? widget.userItemBuilder!(context, user, selected)
                 : Column(
                     mainAxisAlignment: MainAxisAlignment.center,
                     crossAxisAlignment: CrossAxisAlignment.center,
@@ -374,7 +375,7 @@ class _UserListViewState extends State<UserListView>
                           width: 12,
                         ),
                         onTap: (user) =>
-                            widget.onUserTap(user, widget.userWidget),
+                            widget.onUserTap!(user, widget.userWidget),
                         onLongPress: widget.onUserLongPress,
                       ),
                       SizedBox(height: 4),
@@ -424,7 +425,7 @@ class _UserListViewState extends State<UserListView>
             height: 100,
             padding: EdgeInsets.all(32),
             child: Center(
-              child: snapshot.data ? CircularProgressIndicator() : Container(),
+              child: snapshot.data! ? CircularProgressIndicator() : Container(),
             ),
           );
         });

packages/stream_chat_flutter/lib/src/user_reaction_display.dart

@@ -1,12 +1,12 @@
 import 'package:flutter/material.dart';
-import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 import 'package:stream_chat_flutter/src/user_avatar.dart';
+import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 class UserReactionDisplay extends StatelessWidget {
   const UserReactionDisplay({
-    Key key,
+    Key? key,
-    @required this.reactionToEmoji,
+    required this.reactionToEmoji,
-    @required this.message,
+    required this.message,
     this.size = 30,
   }) : super(key: key);
 
@@ -23,12 +23,13 @@ class UserReactionDisplay extends StatelessWidget {
         mainAxisAlignment: MainAxisAlignment.center,
         mainAxisSize: MainAxisSize.min,
         children: reactionToEmoji.keys.map((reactionType) {
-          var firstUserReaction = message.latestReactions.firstWhere(
+          var firstUserReaction = message.latestReactions!
-              (element) => element.type == reactionType, orElse: () {
+              .firstWhere((element) => element.type == reactionType,
-            return null;
+                  orElse: () {
-          });
+                    return null;
+                  } as Reaction Function()?);
 
-          if (firstUserReaction == null) {
+          if (firstUserReaction.user == null) {
             return IconButton(
               iconSize: size,
               icon: Container(),
@@ -39,7 +40,7 @@ class UserReactionDisplay extends StatelessWidget {
           return IconButton(
             iconSize: size,
             icon: UserAvatar(
-              user: firstUserReaction.user,
+              user: firstUserReaction.user!,
               constraints: BoxConstraints(
                 maxHeight: size - 5,
                 maxWidth: size - 5,

packages/stream_chat_flutter/lib/src/utils.dart

@@ -7,8 +7,8 @@ import 'package:url_launcher/url_launcher.dart';
 import '../stream_chat_flutter.dart';
 import 'stream_svg_icon.dart';
 
-Future<void> launchURL(BuildContext context, String url) async {
+Future<void> launchURL(BuildContext context, String? url) async {
-  if (await canLaunch(url)) {
+  if (url != null && await canLaunch(url)) {
     await launch(url);
   } else {
     // ignore: deprecated_member_use
@@ -20,13 +20,13 @@ Future<void> launchURL(BuildContext context, String url) async {
   }
 }
 
-Future<bool> showConfirmationDialog(
+Future<bool?> showConfirmationDialog(
   BuildContext context, {
-  String title,
+  String? title,
-  Widget icon,
+  Widget? icon,
-  String question,
+  String? question,
-  String okText,
+  String? okText,
-  String cancelText,
+  String? cancelText,
 }) {
   return showModalBottomSheet(
       backgroundColor: StreamChatTheme.of(context).colorTheme.white,
@@ -46,17 +46,17 @@ Future<bool> showConfirmationDialog(
               if (icon != null) icon,
               SizedBox(height: 26.0),
               Text(
-                title,
+                title!,
                 style: StreamChatTheme.of(context).textTheme.headlineBold,
               ),
               SizedBox(height: 7.0),
               Text(
-                question,
+                question!,
                 textAlign: TextAlign.center,
               ),
               SizedBox(height: 36.0),
               Container(
-                color: effect.color.withOpacity(effect.alpha ?? 1),
+                color: effect.color!.withOpacity(effect.alpha ?? 1),
                 height: 1,
               ),
               Row(
@@ -69,7 +69,7 @@ Future<bool> showConfirmationDialog(
                           Navigator.of(context).pop(false);
                         },
                         child: Text(
-                          cancelText,
+                          cancelText!,
                           style: StreamChatTheme.of(context)
                               .textTheme
                               .bodyBold
@@ -90,7 +90,7 @@ Future<bool> showConfirmationDialog(
                           Navigator.pop(context, true);
                         },
                         child: Text(
-                          okText,
+                          okText!,
                           style: StreamChatTheme.of(context)
                               .textTheme
                               .bodyBold
@@ -110,17 +110,17 @@ Future<bool> showConfirmationDialog(
       });
 }
 
-Future<bool> showInfoDialog(
+Future<bool?> showInfoDialog(
   BuildContext context, {
-  String title,
+  String? title,
-  Widget icon,
+  Widget? icon,
-  String details,
+  String? details,
-  String okText,
+  String? okText,
-  StreamChatThemeData theme,
+  StreamChatThemeData? theme,
 }) {
   return showModalBottomSheet(
-    backgroundColor: theme?.colorTheme?.white ??
+    backgroundColor:
-        StreamChatTheme.of(context).colorTheme.white,
+        theme?.colorTheme.white ?? StreamChatTheme.of(context).colorTheme.white,
     context: context,
     shape: RoundedRectangleBorder(
         borderRadius: BorderRadius.only(
@@ -140,19 +140,19 @@ Future<bool> showInfoDialog(
               height: 26.0,
             ),
             Text(
-              title,
+              title!,
-              style: theme?.textTheme?.headlineBold ??
+              style: theme?.textTheme.headlineBold ??
                   StreamChatTheme.of(context).textTheme.headlineBold,
             ),
             SizedBox(
               height: 7.0,
             ),
-            Text(details),
+            Text(details!),
             SizedBox(
               height: 36.0,
             ),
             Container(
-              color: theme?.colorTheme?.black?.withOpacity(.08) ??
+              color: theme?.colorTheme.black.withOpacity(.08) ??
                   StreamChatTheme.of(context).colorTheme.black.withOpacity(.08),
               height: 1.0,
             ),
@@ -162,9 +162,9 @@ Future<bool> showInfoDialog(
                   Navigator.of(context).pop();
                 },
                 child: Text(
-                  okText,
+                  okText!,
                   style: TextStyle(
-                    color: theme?.colorTheme?.black?.withOpacity(0.5) ??
+                    color: theme?.colorTheme.black.withOpacity(0.5) ??
                         StreamChatTheme.of(context).colorTheme.accentBlue,
                     fontWeight: FontWeight.w400,
                   ),
@@ -183,7 +183,7 @@ String getRandomPicUrl(User user) =>
     'https://getstream.io/random_png/?id=${user.id}&name=${user.name}';
 
 /// Get websiteName from [hostName]
-String getWebsiteName(String hostName) {
+String? getWebsiteName(String hostName) {
   switch (hostName) {
     case 'reddit':
       return 'Reddit';
@@ -292,62 +292,44 @@ String fileSize(dynamic size, [int round = 2]) {
 }
 
 ///
-StreamSvgIcon getFileTypeImage(String type) {
+StreamSvgIcon getFileTypeImage(String? type) {
   switch (type) {
     case '7z':
       return StreamSvgIcon.filetype7z();
-      break;
     case 'csv':
       return StreamSvgIcon.filetypeCsv();
-      break;
     case 'doc':
       return StreamSvgIcon.filetypeDoc();
-      break;
     case 'docx':
       return StreamSvgIcon.filetypeDocx();
-      break;
     case 'html':
       return StreamSvgIcon.filetypeHtml();
-      break;
     case 'md':
       return StreamSvgIcon.filetypeMd();
-      break;
     case 'odt':
       return StreamSvgIcon.filetypeOdt();
-      break;
     case 'pdf':
       return StreamSvgIcon.filetypePdf();
-      break;
     case 'ppt':
       return StreamSvgIcon.filetypePpt();
-      break;
     case 'pptx':
       return StreamSvgIcon.filetypePptx();
-      break;
     case 'rar':
       return StreamSvgIcon.filetypeRar();
-      break;
     case 'rtf':
       return StreamSvgIcon.filetypeRtf();
-      break;
     case 'tar':
       return StreamSvgIcon.filetypeTar();
-      break;
     case 'txt':
       return StreamSvgIcon.filetypeTxt();
-      break;
     case 'xls':
       return StreamSvgIcon.filetypeXls();
-      break;
     case 'xlsx':
       return StreamSvgIcon.filetypeXlsx();
-      break;
     case 'zip':
       return StreamSvgIcon.filetypeZip();
-      break;
     default:
       return StreamSvgIcon.filetypeGeneric();
-      break;
   }
 }
 

packages/stream_chat_flutter/lib/src/video_service.dart

@@ -4,7 +4,6 @@ import 'dart:typed_data';
 import 'package:synchronized/synchronized.dart';
 import 'package:video_compress/video_compress.dart';
 import 'package:video_thumbnail/video_thumbnail.dart';
-import 'package:meta/meta.dart';
 
 class IVideoService {
   static final IVideoService instance = IVideoService._();
@@ -27,10 +26,10 @@ class IVideoService {
   /// );
   /// debugPrint(info.toJson());
   /// ```
-  Future<MediaInfo> compressVideo(String path) async {
+  Future<MediaInfo?> compressVideo(String? path) async {
     return _lock.synchronized(() {
       return VideoCompress.compressVideo(
-        path,
+        path!,
       );
     });
   }
@@ -39,8 +38,8 @@ class IVideoService {
   /// The video can be a local video file, or an URL repreents iOS or Android native supported video format.
   /// Speicify the maximum height or width for the thumbnail or 0 for same resolution as the original video.
   /// The lower quality value creates lower quality of the thumbnail image, but it gets ignored for PNG format.
-  Future<Uint8List> generateVideoThumbnail({
+  Future<Uint8List?> generateVideoThumbnail({
-    @required String video,
+    required String video,
     ImageFormat imageFormat = ImageFormat.PNG,
     int maxHeight = 0,
     int maxWidth = 0,

packages/stream_chat_flutter/lib/src/video_thumbnail_image.dart

@@ -9,17 +9,17 @@ import 'stream_svg_icon.dart';
 import 'video_service.dart';
 
 class VideoThumbnailImage extends StatefulWidget {
-  final String video;
+  final String? video;
-  final double width;
+  final double? width;
-  final double height;
+  final double? height;
-  final BoxFit fit;
+  final BoxFit? fit;
   final ImageFormat format;
-  final Widget Function(BuildContext, Object) errorBuilder;
+  final Widget Function(BuildContext, Object?)? errorBuilder;
-  final WidgetBuilder placeholderBuilder;
+  final WidgetBuilder? placeholderBuilder;
 
   const VideoThumbnailImage({
-    Key key,
+    Key? key,
-    @required this.video,
+    required this.video,
     this.width,
     this.height,
     this.fit,
@@ -33,12 +33,12 @@ class VideoThumbnailImage extends StatefulWidget {
 }
 
 class _VideoThumbnailImageState extends State<VideoThumbnailImage> {
-  Future<Uint8List> thumbnailFuture;
+  late Future<Uint8List?> thumbnailFuture;
 
   @override
   void initState() {
     thumbnailFuture = VideoService.generateVideoThumbnail(
-      video: widget.video,
+      video: widget.video!,
       imageFormat: widget.format,
     );
     super.initState();
@@ -48,7 +48,7 @@ class _VideoThumbnailImageState extends State<VideoThumbnailImage> {
   void didUpdateWidget(covariant VideoThumbnailImage oldWidget) {
     if (oldWidget.video != widget.video || oldWidget.format != widget.format) {
       thumbnailFuture = VideoService.generateVideoThumbnail(
-        video: widget.video,
+        video: widget.video!,
         imageFormat: widget.format,
       );
     }
@@ -57,13 +57,13 @@ class _VideoThumbnailImageState extends State<VideoThumbnailImage> {
 
   @override
   Widget build(BuildContext context) {
-    return FutureBuilder<Uint8List>(
+    return FutureBuilder<Uint8List?>(
       future: thumbnailFuture,
       builder: (context, snapshot) {
         return AnimatedSwitcher(
           duration: const Duration(milliseconds: 350),
           child: Builder(
-            key: ValueKey<AsyncSnapshot<Uint8List>>(snapshot),
+            key: ValueKey<AsyncSnapshot<Uint8List?>>(snapshot),
             builder: (_) {
               if (snapshot.hasError) {
                 return widget.errorBuilder?.call(context, snapshot.error) ??
@@ -90,7 +90,7 @@ class _VideoThumbnailImageState extends State<VideoThumbnailImage> {
                 );
               }
               return Image.memory(
-                snapshot.data,
+                snapshot.data!,
                 fit: widget.fit,
                 height: widget.height,
                 width: widget.width,

packages/stream_chat_flutter/pubspec.yaml

@@ -8,7 +8,7 @@ issue_tracker: https://github.com/GetStream/stream-chat-flutter/issues
 publish_to: none
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:
@@ -19,7 +19,7 @@ dependencies:
   scrollable_positioned_list: ^0.2.0-nullsafety.0
   jiffy: ^4.1.0
   flutter_svg: ^0.21.0+1
-  flutter_portal: ^0.4.0-nullsafety.0
+  flutter_portal: ^0.4.0
   cached_network_image: ^3.0.0
   shimmer: ^2.0.0-nullsafety.0
   flutter_markdown: ^0.6.1
@@ -48,6 +48,7 @@ dependencies:
   characters: ^1.1.0
   path_provider: ^2.0.1
   video_thumbnail: ^0.3.3
+  collection: ^1.15.0
 
 dependency_overrides:
   stream_chat:
@@ -66,7 +67,7 @@ flutter:
 dev_dependencies:
   flutter_test:
     sdk: flutter
-  mockito: ^5.0.3
+  mocktail: ^0.1.2
   pedantic: ^1.11.0
   golden_toolkit: ^0.9.0
   

packages/stream_chat_flutter/test/src/attachment_actions_modal_test.dart

@@ -2,19 +2,19 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/attachment_actions_modal.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
 
 class MockAttachmentDownloader extends Mock {
-  ProgressCallback progressCallback;
+  ProgressCallback? progressCallback;
   Completer<String> completer = Completer();
 
   Future<String> call(
     Attachment attachment, {
-    ProgressCallback progressCallback,
+    ProgressCallback? progressCallback,
   }) {
     this.progressCallback = progressCallback;
     return completer.future;
@@ -22,17 +22,22 @@ class MockAttachmentDownloader extends Mock {
 }
 
 void main() {
+  setUpAll(() {
+    registerFallbackValue(MaterialPageRoute(builder: (context) => SizedBox()));
+    registerFallbackValue(Message());
+  });
+
   testWidgets(
     'it should show all the actions',
     (WidgetTester tester) async {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidget(
         MaterialApp(
           theme: themeData,
@@ -70,11 +75,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id2'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id2'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidget(
         MaterialApp(
           theme: themeData,
@@ -112,11 +117,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidget(
         MaterialApp(
           theme: themeData,
@@ -153,11 +158,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       final mockObserver = MockNavigatorObserver();
 
@@ -190,7 +195,7 @@ void main() {
         ),
       );
       await tester.tap(find.text('Reply'));
-      verify(mockObserver.didPop(any, any));
+      verify(() => mockObserver.didPop(any(), any()));
     },
   );
 
@@ -200,11 +205,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       final onShowMessage = MockVoidCallback();
 
       await tester.pumpWidget(
@@ -234,7 +239,7 @@ void main() {
         ),
       );
       await tester.tap(find.text('Show in Chat'));
-      verify(onShowMessage.call()).called(1);
+      verify(() => onShowMessage.call()).called(1);
     },
   );
 
@@ -245,11 +250,11 @@ void main() {
       final clientState = MockClientState();
       final mockChannel = MockChannel();
 
-      when(mockChannel.updateMessage(any)).thenAnswer((_) {
+      when(() => mockChannel.updateMessage(any())).thenAnswer((_) async {
-        return;
+        return UpdateMessageResponse();
       });
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final message = Message(
         text: 'test',
@@ -287,11 +292,11 @@ void main() {
         ),
       );
       await tester.tap(find.text('Delete'));
-      verify(mockChannel.updateMessage(message.copyWith(
+      verify(() => mockChannel.updateMessage(message.copyWith(
-        attachments: [
+            attachments: [
-          message.attachments[1],
+              message.attachments[1],
-        ],
+            ],
-      ))).called(1);
+          ))).called(1);
     },
   );
 
@@ -302,11 +307,11 @@ void main() {
       final clientState = MockClientState();
       final mockChannel = MockChannel();
 
-      when(mockChannel.updateMessage(any)).thenAnswer((_) {
+      when(() => mockChannel.updateMessage(any())).thenAnswer((_) async {
-        return;
+        return UpdateMessageResponse();
       });
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final message = Message(
         text: 'test',
@@ -340,9 +345,9 @@ void main() {
         ),
       );
       await tester.tap(find.text('Delete'));
-      verify(mockChannel.updateMessage(message.copyWith(
+      verify(() => mockChannel.updateMessage(message.copyWith(
-        attachments: [],
+            attachments: [],
-      ))).called(1);
+          ))).called(1);
     },
   );
 
@@ -353,11 +358,11 @@ void main() {
       final clientState = MockClientState();
       final mockChannel = MockChannel();
 
-      when(mockChannel.deleteMessage(any)).thenAnswer((_) {
+      when(() => mockChannel.deleteMessage(any())).thenAnswer((_) async {
-        return;
+        return EmptyResponse();
       });
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final message = Message(
         user: User(
@@ -390,7 +395,7 @@ void main() {
         ),
       );
       await tester.tap(find.text('Delete'));
-      verify(mockChannel.deleteMessage(message)).called(1);
+      verify(() => mockChannel.deleteMessage(message)).called(1);
     },
   );
 
@@ -400,8 +405,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final imageDownloader = MockAttachmentDownloader();
 
@@ -435,15 +440,15 @@ void main() {
 
       await tester.tap(find.text('Save Image'));
 
-      imageDownloader.progressCallback(0, 100);
+      imageDownloader.progressCallback!(0, 100);
       await tester.pump();
       expect(find.text('0%'), findsOneWidget);
 
-      imageDownloader.progressCallback(50, 100);
+      imageDownloader.progressCallback!(50, 100);
       await tester.pump();
       expect(find.text('50%'), findsOneWidget);
 
-      imageDownloader.progressCallback(100, 100);
+      imageDownloader.progressCallback!(100, 100);
       imageDownloader.completer.complete('path');
       await tester.pump();
       expect(find.byKey(Key('completedIcon')), findsOneWidget);
@@ -457,8 +462,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final fileDownloader = MockAttachmentDownloader();
 
@@ -492,15 +497,15 @@ void main() {
 
       await tester.tap(find.text('Save Video'));
 
-      fileDownloader.progressCallback(0, 100);
+      fileDownloader.progressCallback!(0, 100);
       await tester.pump();
       expect(find.text('0%'), findsOneWidget);
 
-      fileDownloader.progressCallback(50, 100);
+      fileDownloader.progressCallback!(50, 100);
       await tester.pump();
       expect(find.text('50%'), findsOneWidget);
 
-      fileDownloader.progressCallback(100, 100);
+      fileDownloader.progressCallback!(100, 100);
       fileDownloader.completer.complete('path');
       await tester.pump();
       expect(find.byKey(Key('completedIcon')), findsOneWidget);

packages/stream_chat_flutter/test/src/attachment_widgets_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -12,10 +12,10 @@ void main() {
       final channel = MockChannel();
       final channelState = MockChannelState();
 
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(

packages/stream_chat_flutter/test/src/back_button_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/back_button.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
@@ -19,7 +19,7 @@ void main() {
               return Material(
                 child: Center(
                   child: StreamChatTheme(
-                    data: StreamChatThemeData.getDefaultTheme(theme),
+                    data: StreamChatThemeData.fromTheme(theme),
                     child: StreamBackButton(),
                   ),
                 ),
@@ -51,7 +51,7 @@ void main() {
           home: Material(
             child: Center(
               child: StreamChatTheme(
-                data: StreamChatThemeData.getDefaultTheme(theme),
+                data: StreamChatThemeData.fromTheme(theme),
                 child: StreamBackButton(),
               ),
             ),
@@ -82,7 +82,7 @@ void main() {
               return Material(
                 child: Center(
                   child: StreamChatTheme(
-                    data: StreamChatThemeData.getDefaultTheme(theme),
+                    data: StreamChatThemeData.fromTheme(theme),
                     child: StreamBackButton(
                       onPressed: () => customCallbackWasCalled = true,
                     ),
@@ -121,7 +121,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(0));
 
       await tester.pumpWidget(
         MaterialApp(

packages/stream_chat_flutter/test/src/channel_header_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/channel_info.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
@@ -16,28 +16,33 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => client.wsConnectionStatusStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((_) => Stream.value(ConnectionStatus.connected));
+      when(() => channelState.unreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
@@ -72,35 +77,38 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.disconnected));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -131,36 +139,38 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -194,33 +204,38 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
+      when(() => client.wsConnectionStatusStream)
+          .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -263,34 +278,35 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.disconnected));
 
       await tester.pumpWidget(MaterialApp(
@@ -328,33 +344,38 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
+      when(() => client.wsConnectionStatusStream)
+          .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
 
       var backPressed = false;
       var imageTapped = false;

packages/stream_chat_flutter/test/src/channel_image_test.dart

@@ -1,7 +1,7 @@
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/group_image.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
@@ -16,15 +16,15 @@ void main() {
       final channel = MockChannel();
       final channelState = MockChannelState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
             'image': 'imagetest',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
         'image': 'imagetest',
       });
@@ -55,17 +55,17 @@ void main() {
       final channel = MockChannel();
       final channelState = MockChannelState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
@@ -80,7 +80,7 @@ void main() {
               ),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id2',
           user: User(
@@ -95,7 +95,7 @@ void main() {
           user: User(id: 'user-id'),
         )
       ]);
-      when(clientState.usersStream).thenAnswer((i) => Stream.value({
+      when(() => clientState.usersStream).thenAnswer((i) => Stream.value({
             'user-id2': User(
               id: 'user-id2',
               extraData: {
@@ -103,7 +103,7 @@ void main() {
               },
             ),
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
@@ -133,17 +133,17 @@ void main() {
       final channel = MockChannel();
       final channelState = MockChannelState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(
@@ -172,7 +172,7 @@ void main() {
               ),
             ),
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(
@@ -230,15 +230,15 @@ void main() {
       final channel = MockChannel();
       final channelState = MockChannelState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
             'image': 'imagetest',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
         'image': 'imagetest',
       });

packages/stream_chat_flutter/test/src/channel_list_header_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -12,9 +12,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connected));
 
       await tester.pumpWidget(
@@ -42,9 +42,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.disconnected));
 
       await tester.pumpWidget(
@@ -71,9 +71,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
 
       await tester.pumpWidget(
@@ -100,9 +100,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
 
       await tester.pumpWidget(
@@ -140,9 +140,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
 
       var tapped = false;
@@ -174,9 +174,9 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(client.wsConnectionStatusStream)
+      when(() => client.wsConnectionStatusStream)
           .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
 
       var tapped = 0;

packages/stream_chat_flutter/test/src/channel_name_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,40 +15,41 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(channelState.messages).thenReturn([
+      when(() => channelState.messages).thenReturn([
         Message(
           text: 'hello',
           user: User(id: 'other-user'),
         )
       ]);
-      when(channelState.messagesStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.messagesStream).thenAnswer((i) => Stream.value([
             Message(
               text: 'hello',
               user: User(id: 'other-user'),

packages/stream_chat_flutter/test/src/channel_preview_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,50 +15,55 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(channel.cid).thenReturn('cid');
+      when(() => channel.cid).thenReturn('cid');
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test name',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test name',
       });
-      when(clientState.channels).thenReturn({
+      when(() => clientState.channels).thenReturn({
-        channel.cid: channel,
+        channel.cid!: channel,
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(channelState.messages).thenReturn([
+      when(() => channelState.messages).thenReturn([
         Message(
           text: 'hello',
           user: User(id: 'other-user'),
         )
       ]);
-      when(channelState.messagesStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.messagesStream).thenAnswer((i) => Stream.value([
             Message(
               text: 'hello',
               user: User(id: 'other-user'),
             )
           ]));
 
+      when(() => channelState.typingEvents).thenReturn([]);
+      when(() => channelState.typingEventsStream)
+          .thenAnswer((_) => Stream.value([]));
+
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
           client: client,

packages/stream_chat_flutter/test/src/date_divider_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -12,8 +12,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(

packages/stream_chat_flutter/test/src/deleted_message_test.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:golden_toolkit/golden_toolkit.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -13,8 +13,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -45,21 +45,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       final materialTheme = ThemeData.light();
@@ -98,21 +97,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       final materialTheme = ThemeData.dark();
@@ -151,21 +149,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       final materialTheme = ThemeData.light();

packages/stream_chat_flutter/test/src/full_screen_media_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:photo_view/photo_view.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
@@ -16,51 +16,52 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(channelState.messages).thenReturn([
+      when(() => channelState.messages).thenReturn([
         Message(
           text: 'hello',
           user: User(id: 'other-user'),
         )
       ]);
-      when(channelState.messagesStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.messagesStream).thenAnswer((i) => Stream.value([
             Message(
               text: 'hello',
               user: User(id: 'other-user'),
             )
           ]));
 
-      when(channelState.typingEvents).thenAnswer((i) => [
+      when(() => channelState.typingEvents).thenAnswer((i) => [
             User(id: 'other-user', extraData: {'name': 'demo'})
           ]);
-      when(channelState.typingEventsStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.typingEventsStream)
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+          .thenAnswer((i) => Stream.value([
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+                User(id: 'other-user', extraData: {'name': 'demo'}),
-          ]));
+                User(id: 'other-user', extraData: {'name': 'demo'}),
+              ]));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -78,7 +79,6 @@ void main() {
               message: Message(
                 createdAt: DateTime.now(),
               ),
-              sentAt: DateTime.now(),
             ),
           ),
         ),

packages/stream_chat_flutter/test/src/image_footer_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,17 +15,17 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
@@ -37,7 +37,9 @@ void main() {
             child: WillPopScope(
               onWillPop: () async => false,
               child: Scaffold(
-                body: ImageFooter(),
+                body: ImageFooter(
+                  message: Message(),
+                ),
               ),
             ),
           ),

packages/stream_chat_flutter/test/src/info_tile_test.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_portal/flutter_portal.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -13,8 +13,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -43,8 +43,8 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(

packages/stream_chat_flutter/test/src/message_action_modal_test.dart

@@ -1,23 +1,28 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/message_actions_modal.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
 
 void main() {
+  setUpAll(() {
+    registerFallbackValue(MaterialPageRoute(builder: (context) => SizedBox()));
+    registerFallbackValue(Message());
+  });
+
   testWidgets(
     'it should show the all actions',
     (WidgetTester tester) async {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidget(
         MaterialApp(
           theme: themeData,
@@ -55,11 +60,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidget(
         MaterialApp(
           theme: themeData,
@@ -102,11 +107,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       var tapped = false;
       await tester.pumpWidget(
@@ -156,11 +161,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       var tapped = false;
 
@@ -173,7 +178,7 @@ void main() {
             child: Container(
               child: MessageActionsModal(
                 onReplyTap: (m) {
-                  return tapped = true;
+                  tapped = true;
                 },
                 message: Message(
                   text: 'test',
@@ -201,11 +206,11 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       var tapped = false;
 
@@ -218,7 +223,7 @@ void main() {
             child: Container(
               child: MessageActionsModal(
                 onThreadReplyTap: (m) {
-                  return tapped = true;
+                  tapped = true;
                 },
                 message: Message(
                   text: 'test',
@@ -247,12 +252,11 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -298,12 +302,11 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -352,12 +355,11 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       var tapped = false;
 
@@ -404,12 +406,13 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.sendMessage(any()))
+          .thenAnswer((_) async => SendMessageResponse());
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -443,7 +446,7 @@ void main() {
 
       await tester.tap(find.text('Resend'));
 
-      verify(channel.sendMessage(any)).called(1);
+      verify(() => channel.sendMessage(any())).called(1);
     },
   );
 
@@ -454,12 +457,13 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.updateMessage(any()))
+          .thenAnswer((_) async => UpdateMessageResponse());
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -493,7 +497,7 @@ void main() {
 
       await tester.tap(find.text('Resend Edited Message'));
 
-      verify(channel.updateMessage(any)).called(1);
+      verify(() => channel.updateMessage(any())).called(1);
     },
   );
 
@@ -504,12 +508,11 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -549,7 +552,7 @@ void main() {
       await tester.tap(find.text('FLAG'));
       await tester.pumpAndSettle();
 
-      verify(client.flagMessage('testid')).called(1);
+      verify(() => client.flagMessage('testid')).called(1);
     },
   );
 
@@ -560,16 +563,15 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => client.flagMessage(any())).thenThrow(ApiError(
-      when(client.flagMessage(any)).thenThrow(ApiError(
         '{}',
         500,
       ));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -620,16 +622,15 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => client.flagMessage(any())).thenThrow(ApiError(
-      when(client.flagMessage(any)).thenThrow(ApiError(
         '{"code":4}',
         400,
       ));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -680,12 +681,11 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(
@@ -725,7 +725,7 @@ void main() {
       await tester.tap(find.text('DELETE'));
       await tester.pumpAndSettle();
 
-      verify(channel.deleteMessage(any)).called(1);
+      verify(() => channel.deleteMessage(any())).called(1);
     },
   );
 
@@ -736,16 +736,15 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.deleteMessage(any())).thenThrow(ApiError(
-      when(channel.deleteMessage(any)).thenThrow(ApiError(
         '{}',
         500,
       ));
 
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       await tester.pumpWidget(
         MaterialApp(

packages/stream_chat_flutter/test/src/message_input_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,51 +15,52 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(channelState.messages).thenReturn([
+      when(() => channelState.messages).thenReturn([
         Message(
           text: 'hello',
           user: User(id: 'other-user'),
         )
       ]);
-      when(channelState.messagesStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.messagesStream).thenAnswer((i) => Stream.value([
             Message(
               text: 'hello',
               user: User(id: 'other-user'),
             )
           ]));
 
-      when(channelState.typingEvents).thenAnswer((i) => [
+      when(() => channelState.typingEvents).thenAnswer((i) => [
             User(id: 'other-user', extraData: {'name': 'demo'})
           ]);
-      when(channelState.typingEventsStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.typingEventsStream)
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+          .thenAnswer((i) => Stream.value([
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+                User(id: 'other-user', extraData: {'name': 'demo'}),
-          ]));
+                User(id: 'other-user', extraData: {'name': 'demo'}),
+              ]));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(

packages/stream_chat_flutter/test/src/message_reactions_modal_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/message_reactions_modal.dart';
 import 'package:stream_chat_flutter/src/reaction_bubble.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
@@ -15,10 +15,10 @@ void main() {
       final clientState = MockClientState();
       final themeData = ThemeData();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       final message = Message(
         id: 'test',
@@ -75,10 +75,10 @@ void main() {
       final clientState = MockClientState();
       final themeData = ThemeData();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
       final message = Message(
         id: 'test',

packages/stream_chat_flutter/test/src/message_text_test.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -16,19 +16,19 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
       final themeData = ThemeData();
-      final streamTheme = StreamChatThemeData.getDefaultTheme(themeData);
+      final streamTheme = StreamChatThemeData.fromTheme(themeData);
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 

packages/stream_chat_flutter/test/src/mocks.dart

@@ -1,12 +1,20 @@
 import 'package:flutter/material.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter_core/stream_chat_flutter_core.dart';
 
 class MockClient extends Mock implements StreamChatClient {}
 
 class MockClientState extends Mock implements ClientState {}
 
-class MockChannel extends Mock implements Channel {}
+class MockChannel extends Mock implements Channel {
+  @override
+  Future<bool> get initialized async => true;
+
+  @override
+  Future<void> keyStroke([String? parentId]) async {
+    return;
+  }
+}
 
 class MockChannelState extends Mock implements ChannelClientState {}
 

packages/stream_chat_flutter/test/src/reaction_bubble_test.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:golden_toolkit/golden_toolkit.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/src/reaction_bubble.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
@@ -39,10 +39,10 @@ void main() {
       final clientState = MockClientState();
       final themeData = ThemeData.light();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
-      final theme = StreamChatThemeData.getDefaultTheme(themeData);
+      final theme = StreamChatThemeData.fromTheme(themeData);
       await tester.pumpWidgetBuilder(
         StreamChat(
           client: client,
@@ -55,9 +55,9 @@ void main() {
                   user: User(id: 'test'),
                 ),
               ],
-              borderColor: theme.ownMessageTheme.reactionsBorderColor,
+              borderColor: theme.ownMessageTheme.reactionsBorderColor!,
-              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor,
+              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor!,
-              maskColor: theme.ownMessageTheme.reactionsMaskColor,
+              maskColor: theme.ownMessageTheme.reactionsMaskColor!,
             ),
           ),
         ),
@@ -73,15 +73,15 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
       final themeData = ThemeData.dark();
-      final theme = StreamChatThemeData.getDefaultTheme(themeData);
+      final theme = StreamChatThemeData.fromTheme(themeData);
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidgetBuilder(
         StreamChat(
           client: client,
-          streamChatThemeData: StreamChatThemeData.getDefaultTheme(themeData),
+          streamChatThemeData: StreamChatThemeData.fromTheme(themeData),
           child: Container(
             color: Colors.black,
             child: ReactionBubble(
@@ -91,9 +91,9 @@ void main() {
                   user: User(id: 'test'),
                 ),
               ],
-              borderColor: theme.ownMessageTheme.reactionsBorderColor,
+              borderColor: theme.ownMessageTheme.reactionsBorderColor!,
-              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor,
+              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor!,
-              maskColor: theme.ownMessageTheme.reactionsMaskColor,
+              maskColor: theme.ownMessageTheme.reactionsMaskColor!,
             ),
           ),
         ),
@@ -109,15 +109,15 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
       final themeData = ThemeData.light();
-      final theme = StreamChatThemeData.getDefaultTheme(themeData);
+      final theme = StreamChatThemeData.fromTheme(themeData);
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidgetBuilder(
         StreamChat(
           client: client,
-          streamChatThemeData: StreamChatThemeData.getDefaultTheme(themeData),
+          streamChatThemeData: StreamChatThemeData.fromTheme(themeData),
           child: Container(
             color: Colors.black,
             child: ReactionBubble(
@@ -135,9 +135,9 @@ void main() {
                   user: User(id: 'test'),
                 ),
               ],
-              borderColor: theme.ownMessageTheme.reactionsBorderColor,
+              borderColor: theme.ownMessageTheme.reactionsBorderColor!,
-              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor,
+              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor!,
-              maskColor: theme.ownMessageTheme.reactionsMaskColor,
+              maskColor: theme.ownMessageTheme.reactionsMaskColor!,
             ),
           ),
         ),
@@ -153,15 +153,15 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
       final themeData = ThemeData.dark();
-      final theme = StreamChatThemeData.getDefaultTheme(themeData);
+      final theme = StreamChatThemeData.fromTheme(themeData);
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidgetBuilder(
         StreamChat(
           client: client,
-          streamChatThemeData: StreamChatThemeData.getDefaultTheme(themeData),
+          streamChatThemeData: StreamChatThemeData.fromTheme(themeData),
           child: Container(
             color: Colors.black,
             child: ReactionBubble(
@@ -179,9 +179,9 @@ void main() {
                   user: User(id: 'test'),
                 ),
               ],
-              borderColor: theme.ownMessageTheme.reactionsBorderColor,
+              borderColor: theme.ownMessageTheme.reactionsBorderColor!,
-              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor,
+              backgroundColor: theme.ownMessageTheme.reactionsBackgroundColor!,
-              maskColor: theme.ownMessageTheme.reactionsMaskColor,
+              maskColor: theme.ownMessageTheme.reactionsMaskColor!,
             ),
           ),
         ),
@@ -198,13 +198,13 @@ void main() {
       final clientState = MockClientState();
       final themeData = ThemeData();
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
 
       await tester.pumpWidgetBuilder(
         StreamChat(
           client: client,
-          streamChatThemeData: StreamChatThemeData.getDefaultTheme(themeData),
+          streamChatThemeData: StreamChatThemeData.fromTheme(themeData),
           child: Container(
             child: ReactionBubble(
               reactions: [

packages/stream_chat_flutter/test/src/simple_frame.dart

@@ -3,7 +3,7 @@ import 'package:flutter/material.dart';
 class SimpleFrame extends StatelessWidget {
   final Widget child;
 
-  const SimpleFrame({Key key, @required this.child}) : super(key: key);
+  const SimpleFrame({Key? key, required this.child}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {

packages/stream_chat_flutter/test/src/system_message_test.dart

@@ -1,7 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:golden_toolkit/golden_toolkit.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -16,20 +16,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       var tapped = false;
@@ -67,21 +67,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       await tester.pumpWidgetBuilder(
@@ -119,21 +118,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       await tester.pumpWidgetBuilder(

packages/stream_chat_flutter/test/src/thread_header_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,34 +15,38 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
+      when(() => client.wsConnectionStatusStream)
+          .thenAnswer((_) => Stream.value(ConnectionStatus.connecting));
+      when(() => clientState.totalUnreadCountStream)
+          .thenAnswer((i) => Stream.value(1));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -75,29 +79,29 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.initialized).thenAnswer((_) => Future.value(true));
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.unreadCount).thenReturn(1);
+      when(() => channelState.unreadCount).thenReturn(1);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(1));
+      when(() => channelState.unreadCountStream)
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+          .thenAnswer((i) => Stream.value(1));
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),

packages/stream_chat_flutter/test/src/typing_indicator_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,51 +15,52 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.isMuted).thenReturn(false);
+      when(() => channel.isMuted).thenReturn(false);
-      when(channel.isMutedStream).thenAnswer((i) => Stream.value(false));
+      when(() => channel.isMutedStream).thenAnswer((i) => Stream.value(false));
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
-      when(channelState.membersStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.membersStream).thenAnswer((i) => Stream.value([
             Member(
               userId: 'user-id',
               user: User(id: 'user-id'),
             )
           ]));
-      when(channelState.members).thenReturn([
+      when(() => channelState.members).thenReturn([
         Member(
           userId: 'user-id',
           user: User(id: 'user-id'),
         ),
       ]);
-      when(channelState.messages).thenReturn([
+      when(() => channelState.messages).thenReturn([
         Message(
           text: 'hello',
           user: User(id: 'other-user'),
         )
       ]);
-      when(channelState.messagesStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.messagesStream).thenAnswer((i) => Stream.value([
             Message(
               text: 'hello',
               user: User(id: 'other-user'),
             )
           ]));
 
-      when(channelState.typingEvents).thenAnswer((i) => [
+      when(() => channelState.typingEvents).thenAnswer((i) => [
             User(id: 'other-user', extraData: {'name': 'demo'})
           ]);
-      when(channelState.typingEventsStream).thenAnswer((i) => Stream.value([
+      when(() => channelState.typingEventsStream)
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+          .thenAnswer((i) => Stream.value([
-            User(id: 'other-user', extraData: {'name': 'demo'}),
+                User(id: 'other-user', extraData: {'name': 'demo'}),
-          ]));
+                User(id: 'other-user', extraData: {'name': 'demo'}),
+              ]));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(

packages/stream_chat_flutter/test/src/unread_indicator_test.dart

@@ -1,6 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:mockito/mockito.dart';
+import 'package:mocktail/mocktail.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'mocks.dart';
@@ -15,20 +15,20 @@ void main() {
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channel.extraDataStream).thenAnswer((i) => Stream.value({
+      when(() => channel.extraDataStream).thenAnswer((i) => Stream.value({
             'name': 'test',
           }));
-      when(channel.extraData).thenReturn({
+      when(() => channel.extraData).thenReturn({
         'name': 'test',
       });
 
-      when(clientState.totalUnreadCount).thenReturn(10);
+      when(() => clientState.totalUnreadCount).thenReturn(10);
-      when(clientState.totalUnreadCountStream)
+      when(() => clientState.totalUnreadCountStream)
           .thenAnswer((i) => Stream.value(10));
 
       await tester.pumpWidget(MaterialApp(
@@ -54,19 +54,20 @@ void main() {
       final clientState = MockClientState();
       final channel = MockChannel();
       final channelState = MockChannelState();
-      when(channel.cid).thenReturn('cid');
+      when(() => channel.cid).thenReturn('cid');
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(clientState.channels).thenReturn({
+      when(() => clientState.channels).thenReturn({
-        channel.cid: channel,
+        channel.cid!: channel,
       });
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channelState.unreadCount).thenReturn(0);
+      when(() => channelState.unreadCount).thenReturn(0);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(0));
+      when(() => channelState.unreadCountStream)
+          .thenAnswer((i) => Stream.value(0));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(
@@ -92,20 +93,21 @@ void main() {
       final client = MockClient();
       final clientState = MockClientState();
       final channel = MockChannel();
-      when(channel.cid).thenReturn('cid');
+      when(() => channel.cid).thenReturn('cid');
       final channelState = MockChannelState();
       final lastMessageAt = DateTime.parse('2020-06-22 12:00:00');
 
-      when(client.state).thenReturn(clientState);
+      when(() => client.state).thenReturn(clientState);
-      when(clientState.user).thenReturn(OwnUser(id: 'user-id'));
+      when(() => clientState.user).thenReturn(OwnUser(id: 'user-id'));
-      when(clientState.channels).thenReturn({
+      when(() => clientState.channels).thenReturn({
-        channel.cid: channel,
+        channel.cid!: channel,
       });
-      when(channel.lastMessageAt).thenReturn(lastMessageAt);
+      when(() => channel.lastMessageAt).thenReturn(lastMessageAt);
-      when(channel.state).thenReturn(channelState);
+      when(() => channel.state).thenReturn(channelState);
-      when(channel.client).thenReturn(client);
+      when(() => channel.client).thenReturn(client);
-      when(channelState.unreadCount).thenReturn(100);
+      when(() => channelState.unreadCount).thenReturn(100);
-      when(channelState.unreadCountStream).thenAnswer((i) => Stream.value(100));
+      when(() => channelState.unreadCountStream)
+          .thenAnswer((i) => Stream.value(100));
 
       await tester.pumpWidget(MaterialApp(
         home: StreamChat(

packages/stream_chat_persistence/lib/src/dao/channel_query_dao.dart

@@ -6,7 +6,6 @@ import 'package:stream_chat_persistence/src/db/moor_chat_database.dart';
 import 'package:stream_chat_persistence/src/entity/channel_queries.dart';
 import 'package:stream_chat_persistence/src/entity/channels.dart';
 import 'package:stream_chat_persistence/src/entity/users.dart';
-
 import 'package:stream_chat_persistence/src/mapper/mapper.dart';
 
 part 'channel_query_dao.g.dart';
@@ -93,7 +92,7 @@ class ChannelQueryDao extends DatabaseAccessor<MoorChatDatabase>
 
     final possibleSortingFields = cachedChannels.fold<List<String>>(
         ChannelModel.topLevelFields, (previousValue, element) {
-      final extraData = element.extraData ?? {};
+      final extraData = element.extraData;
       return {...previousValue, ...extraData.keys}.toList();
     });