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stream-chat-flutter/lib/src/message_list_view.dart
T

479 lines
16 KiB
Dart

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:jiffy/jiffy.dart';
import 'package:stream_chat/stream_chat.dart';
import 'package:visibility_detector/visibility_detector.dart';
import '../stream_chat_flutter.dart';
import 'date_divider.dart';
import 'message_widget.dart';
import 'stream_channel.dart';
typedef MessageBuilder = Widget Function(BuildContext, Message, int index);
typedef ParentMessageBuilder = Widget Function(BuildContext, Message);
typedef ThreadBuilder = Widget Function(BuildContext context, Message parent);
typedef ThreadTapCallback = void Function(Message, Widget);
/// ![screenshot](https://raw.githubusercontent.com/GetStream/stream-chat-flutter/master/screenshots/message_listview.png)
/// ![screenshot](https://raw.githubusercontent.com/GetStream/stream-chat-flutter/master/screenshots/message_listview_paint.png)
///
/// It shows the list of messages of the current channel.
///
/// ```dart
/// class ChannelPage extends StatelessWidget {
/// const ChannelPage({
/// Key key,
/// }) : super(key: key);
///
/// @override
/// Widget build(BuildContext context) {
/// return Scaffold(
/// appBar: ChannelHeader(),
/// body: Column(
/// children: <Widget>[
/// Expanded(
/// child: MessageListView(
/// threadBuilder: (_, parentMessage) {
/// return ThreadPage(
/// parent: parentMessage,
/// );
/// },
/// ),
/// ),
/// MessageInput(),
/// ],
/// ),
/// );
/// }
/// }
/// ```
///
///
/// Make sure to have a [StreamChannel] ancestor in order to provide the information about the channels.
/// The widget uses a [ListView.custom] to render the list of channels.
///
/// The widget components render the ui based on the first ancestor of type [StreamChatTheme].
/// Modify it to change the widget appearance.
class MessageListView extends StatefulWidget {
/// Instantiate a new MessageListView
MessageListView({
Key key,
this.messageBuilder,
this.parentMessageBuilder,
this.parentMessage,
this.threadBuilder,
this.onThreadTap,
this.showOtherMessageUsername = false,
this.showVideoFullScreen = true,
this.onMentionTap,
this.onMessageActions,
this.attachmentBuilders,
this.dateDividerBuilder,
}) : super(key: key);
/// Function used to build a custom message widget
final MessageBuilder messageBuilder;
/// Function used to build a custom parent message widget
final ParentMessageBuilder parentMessageBuilder;
/// Function used to build a custom thread widget
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;
/// Parent message in case of a thread
final Message parentMessage;
/// If true show the other users username next to the timestamp of the message
final bool showOtherMessageUsername;
/// True if the video player will allow fullscreen mode
final bool showVideoFullScreen;
/// Function called on message mention tap
final void Function(User) onMentionTap;
/// Function called on message long press
final Function(BuildContext, Message) onMessageActions;
/// Map that defines a builder for an attachment type
final Map<String, AttachmentBuilder> attachmentBuilders;
/// Builder used to render date dividers
final Widget Function(DateTime) dateDividerBuilder;
@override
_MessageListViewState createState() => _MessageListViewState();
}
class _MessageListViewState extends State<MessageListView> {
static const _newMessageLoadingOffset = 100;
final ScrollController _scrollController = ScrollController();
bool _isBottom = true;
bool _topWasVisible = false;
List<Message> _messages = [];
List<Message> _newMessageList = [];
Function _onThreadTap;
@override
Widget build(BuildContext context) {
final streamChannel = StreamChannel.of(context);
/// TODO: find a better solution when (https://github.com/flutter/flutter/issues/21023) is fixed
return NotificationListener<ScrollNotification>(
onNotification: (_) {
if (_scrollController.offset < 150 && _newMessageList.isNotEmpty) {
setState(() {
_messages.insertAll(0, _newMessageList);
_newMessageList.clear();
});
}
return true;
},
child: ListView.custom(
key: Key('messageListView'),
physics: AlwaysScrollableScrollPhysics(),
controller: _scrollController,
reverse: true,
childrenDelegate: SliverChildBuilderDelegate(
(context, i) {
if (i == _messages.length + 1) {
if (widget.parentMessage != null) {
if (widget.parentMessageBuilder != null) {
return widget.parentMessageBuilder(
context,
widget.parentMessage,
);
} else {
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
MessageWidget(
key: ValueKey<String>(
'PARENT-MESSAGE-${widget.parentMessage.id}'),
previousMessage: null,
message: widget.parentMessage,
nextMessage: null,
onThreadTap: _onThreadTap,
isParent: true,
showVideoFullScreen: widget.showVideoFullScreen,
showOtherMessageUsername:
widget.showOtherMessageUsername,
onMentionTap: widget.onMentionTap,
onMessageActions: widget.onMessageActions,
attachmentBuilders: widget.attachmentBuilders,
),
Padding(
padding: const EdgeInsets.symmetric(horizontal: 32),
child: Container(
padding: const EdgeInsets.all(8),
child: Text(
'Start of thread',
textAlign: TextAlign.center,
),
color: Theme.of(context).accentColor.withAlpha(50),
),
),
],
);
}
} else {
return SizedBox();
}
}
if (i == _messages.length) {
return _buildLoadingIndicator(streamChannel);
}
final message = _messages[i];
final previousMessage =
i < _messages.length - 1 ? _messages[i + 1] : null;
final nextMessage = i > 0 ? _messages[i - 1] : null;
Widget messageWidget;
if (i == 0) {
messageWidget = _buildBottomMessage(
streamChannel,
previousMessage,
message,
context,
);
} else if (i == _messages.length - 1) {
messageWidget = _buildTopMessage(
message,
nextMessage,
streamChannel,
context,
);
} else {
if (widget.messageBuilder != null) {
messageWidget = Builder(
key: ValueKey<String>('MESSAGE-${message.id}'),
builder: (_) => widget.messageBuilder(context, message, i),
);
} else {
messageWidget = MessageWidget(
key: ValueKey<String>('MESSAGE-${message.id}'),
previousMessage: previousMessage,
message: message,
nextMessage: nextMessage,
onThreadTap: _onThreadTap,
showOtherMessageUsername: widget.showOtherMessageUsername,
showVideoFullScreen: widget.showVideoFullScreen,
onMentionTap: widget.onMentionTap,
onMessageActions: widget.onMessageActions,
attachmentBuilders: widget.attachmentBuilders,
);
}
}
if (nextMessage != null &&
!Jiffy(message.createdAt.toLocal())
.isSame(nextMessage.createdAt.toLocal(), Units.DAY)) {
return Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
messageWidget,
widget.dateDividerBuilder != null
? widget
.dateDividerBuilder(nextMessage.createdAt.toLocal())
: DateDivider(
dateTime: nextMessage.createdAt.toLocal(),
),
],
);
}
return messageWidget;
},
childCount: _messages.length + 2,
findChildIndexCallback: (key) {
final ValueKey<String> valueKey = key;
final index = _messages
.indexWhere((m) => 'MESSAGE-${m.id}' == valueKey.value);
return index != -1 ? index : null;
},
),
),
);
}
Container _buildLoadingIndicator(StreamChannelState streamChannel) {
return Container(
height: 50,
child: StreamBuilder<bool>(
stream: streamChannel.queryMessage,
initialData: false,
builder: (context, snapshot) {
if (snapshot.hasError) {
return Container(
color: Color(0xffd0021B).withAlpha(26),
child: Center(
child: Text('Error loading messages'),
),
);
}
if (!snapshot.data) {
return Container();
}
return Center(
child: Padding(
padding: const EdgeInsets.all(8.0),
child: CircularProgressIndicator(),
),
);
}),
);
}
Widget _buildTopMessage(
Message message,
Message nextMessage,
StreamChannelState streamChannelState,
BuildContext context,
) {
Widget messageWidget;
if (widget.messageBuilder != null) {
messageWidget = Builder(
key: ValueKey<String>('MESSAGE-${message.id}'),
builder: (_) => widget.messageBuilder(context, message, 0),
);
} else {
messageWidget = MessageWidget(
key: ValueKey<String>('MESSAGE-${message.id}'),
previousMessage: null,
message: message,
nextMessage: nextMessage,
onThreadTap: _onThreadTap,
showVideoFullScreen: widget.showVideoFullScreen,
showOtherMessageUsername: widget.showOtherMessageUsername,
onMentionTap: widget.onMentionTap,
onMessageActions: widget.onMessageActions,
attachmentBuilders: widget.attachmentBuilders,
);
}
return VisibilityDetector(
key: ValueKey<String>('TOP-MESSAGE'),
child: messageWidget,
onVisibilityChanged: (visibility) {
final topIsVisible = visibility.visibleBounds != Rect.zero;
if (topIsVisible && !_topWasVisible) {
streamChannelState.queryMessages();
}
_topWasVisible = topIsVisible;
},
);
}
Widget _buildBottomMessage(
StreamChannelState streamChannel,
Message previousMessage,
Message message,
BuildContext context,
) {
Widget messageWidget;
if (widget.messageBuilder != null) {
messageWidget = Builder(
key: ValueKey<String>('MESSAGE-${message.id}'),
builder: (_) => widget.messageBuilder(context, message, 0),
);
} else {
messageWidget = MessageWidget(
key: ValueKey<String>('MESSAGE-${message.id}'),
previousMessage: previousMessage,
message: message,
nextMessage: null,
onThreadTap: _onThreadTap,
showVideoFullScreen: widget.showVideoFullScreen,
showOtherMessageUsername: widget.showOtherMessageUsername,
onMentionTap: widget.onMentionTap,
onMessageActions: widget.onMessageActions,
attachmentBuilders: widget.attachmentBuilders,
);
}
return VisibilityDetector(
key: ValueKey<String>('BOTTOM-MESSAGE'),
onVisibilityChanged: (visibility) {
_isBottom = visibility.visibleBounds != Rect.zero;
if (_isBottom && streamChannel.channel.config?.readEvents == true) {
if (streamChannel.channel.state.unreadCount > 0) {
streamChannel.channel.markRead();
}
}
},
child: messageWidget,
);
}
StreamSubscription _streamListener;
@override
void initState() {
super.initState();
final streamChannel = StreamChannel.of(context);
if (streamChannel.channel.state.unreadCount > 0) {
streamChannel.channel.markRead();
}
Stream<List<Message>> stream;
if (widget.parentMessage == null) {
stream = streamChannel.channel.state.messagesStream;
} else {
streamChannel.getReplies(widget.parentMessage.id);
stream = streamChannel.channel.state.threadsStream
.where((threads) => threads.containsKey(widget.parentMessage.id))
.map((threads) => threads[widget.parentMessage.id]);
}
_streamListener = stream
.map((messages) =>
messages
?.where((m) =>
!(m.status == MessageSendingStatus.FAILED && m.isDeleted))
?.toList() ??
[])
.listen((newMessages) {
newMessages = newMessages.reversed.toList();
if (_messages.isEmpty ||
newMessages.isEmpty ||
newMessages.first.id != _messages.first.id) {
if (!_scrollController.hasClients ||
_scrollController.offset < _newMessageLoadingOffset) {
if (streamChannel.channel.state.unreadCount > 0) {
streamChannel.channel.markRead();
}
setState(() {
_messages = newMessages;
});
} else if (newMessages.first.user.id ==
streamChannel.channel.client.state.user.id) {
_scrollController.jumpTo(0);
WidgetsBinding.instance.addPostFrameCallback((_) {
setState(() {
_messages = newMessages;
});
});
} else {
_newMessageList = newMessages;
}
} else {
setState(() {
_messages = newMessages;
});
}
});
_getOnThreadTap();
}
void _getOnThreadTap() {
if (widget.onThreadTap != null) {
_onThreadTap = (Message message) {
widget.onThreadTap(
message,
widget.threadBuilder != null
? widget.threadBuilder(context, message)
: null);
};
} else if (widget.threadBuilder != null) {
_onThreadTap = (Message message) {
Navigator.push(
context,
MaterialPageRoute(builder: (_) {
return StreamBuilder<Message>(
stream: StreamChannel.of(context)
.channel
.state
.messagesStream
.map((messages) =>
messages.firstWhere((m) => m.id == message.id)),
initialData: message,
builder: (_, snapshot) {
return StreamChannel(
channel: StreamChannel.of(context).channel,
child: widget.threadBuilder(context, snapshot.data),
);
});
}),
);
};
}
}
@override
void dispose() {
_streamListener.cancel();
super.dispose();
}
}