test: add tests for stream chat flutter core (#354)

* test(core): add tests for channels bloc Signed-off-by: Sahil Kumar <[email protected]> * test(core): refactor some tests due to changes in channels bloc Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for channel list core Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for users bloc, minor improvements Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for user list core, minor improvements Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for message search bloc, refactor Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for message search list core, refactor Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for lazy load scroll view Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for stream chat core Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for message list core Signed-off-by: Sahil Kumar <[email protected]> * test(core): add tests for stream channel Signed-off-by: Sahil Kumar <[email protected]> * Fix merge conflicts Signed-off-by: Sahil Kumar <[email protected]> * flutter format Signed-off-by: Sahil Kumar <[email protected]> * fixes Signed-off-by: Sahil Kumar <[email protected]> * update workflow Signed-off-by: Sahil Kumar <[email protected]> * chore(core): fix analyzer issues Signed-off-by: Sahil Kumar <[email protected]> * chore(ui-kit): fix analyzer issues Signed-off-by: Sahil Kumar <[email protected]>
2021-03-30 10:16:12 +02:00
parent cba0b1a391
commit 420d6384c4
35 changed files with 4867 additions and 413 deletions
@@ -130,10 +130,11 @@ class ChannelListCore extends StatefulWidget {
  final PaginationParams pagination;

  @override
-  _ChannelListCoreState createState() => _ChannelListCoreState();
+  ChannelListCoreState createState() => ChannelListCoreState();
 }

-class _ChannelListCoreState extends State<ChannelListCore> {
+/// The current state of the [ChannelListCore].
+class ChannelListCoreState extends State<ChannelListCore> {
  @override
  Widget build(BuildContext context) {
    final channelsBloc = ChannelsBloc.of(context);
@@ -148,7 +149,7 @@ class _ChannelListCoreState extends State<ChannelListCore> {
        stream: channelsBlocState.channelsStream,
        builder: (context, snapshot) {
          if (snapshot.hasError) {
-            return _buildErrorWidget(snapshot, context, channelsBlocState);
+            return widget.errorBuilder(context, snapshot.error);
          }
          if (!snapshot.hasData) {
            return widget.loadingBuilder(context);
@@ -161,18 +162,7 @@ class _ChannelListCoreState extends State<ChannelListCore> {
        },
      );

-  Widget _buildErrorWidget(
-    AsyncSnapshot<List<Channel>> snapshot,
-    BuildContext context,
-    ChannelsBlocState channelsBlocState,
-  ) {
-    if (snapshot.error is Error) {
-      print((snapshot.error as Error).stackTrace);
-    }
-
-    return widget.errorBuilder(context, snapshot.error);
-  }
-
+  /// Fetches initial channels and updates the widget
  Future<void> loadData() {
    final channelsBloc = ChannelsBloc.of(context);
    return channelsBloc.queryChannels(
@@ -183,6 +173,7 @@ class _ChannelListCoreState extends State<ChannelListCore> {
    );
  }

+  /// Fetches more channels with updated pagination and updates the widget
  Future<void> paginateData() {
    final channelsBloc = ChannelsBloc.of(context);
    return channelsBloc.queryChannels(
@@ -223,9 +214,9 @@ class _ChannelListCoreState extends State<ChannelListCore> {

    if (widget.filter?.toString() != oldWidget.filter?.toString() ||
        jsonEncode(widget.sort) != jsonEncode(oldWidget.sort) ||
+        widget.options?.toString() != oldWidget.options?.toString() ||
        widget.pagination?.toJson()?.toString() !=
-            oldWidget.pagination?.toJson()?.toString() ||
-        widget.options?.toString() != oldWidget.options?.toString()) {
+            oldWidget.pagination?.toJson()?.toString()) {
      loadData();
    }
  }
@@ -74,10 +74,9 @@ class ChannelsBlocState extends State<ChannelsBloc>
  /// The current channel list as a stream
  Stream<List<Channel>> get channelsStream => _channelsController.stream;

-  final BehaviorSubject<bool> _queryChannelsLoadingController =
-      BehaviorSubject.seeded(false);
+  final _queryChannelsLoadingController = BehaviorSubject.seeded(false);

-  final BehaviorSubject<List<Channel>> _channelsController = BehaviorSubject();
+  final _channelsController = BehaviorSubject<List<Channel>>();

  /// The stream notifying the state of queryChannel call
  Stream<bool> get queryChannelsLoading =>
@@ -91,15 +90,14 @@ class ChannelsBlocState extends State<ChannelsBloc>
    List<SortOption<ChannelModel>> sortOptions,
    PaginationParams paginationParams,
    Map<String, dynamic> options,
-    bool onlyOffline = false,
  }) async {
    final client = StreamChatCore.of(context).client;

-    if (client.state?.user == null ||
-        _queryChannelsLoadingController.value == true) {
-      return;
+    if (_queryChannelsLoadingController.value == true) return;
+
+    if (_channelsController.hasValue) {
+      _queryChannelsLoadingController.add(true);
    }
-    _queryChannelsLoadingController.sink.add(true);

    try {
      final clear = paginationParams == null ||
@@ -115,15 +113,20 @@ class ChannelsBlocState extends State<ChannelsBloc>
        if (clear) {
          _channelsController.add(channels);
        } else {
-          final l = oldChannels + channels;
-          _channelsController.add(l);
+          final temp = oldChannels + channels;
+          _channelsController.add(temp);
+        }
+        if (_channelsController.hasValue &&
+            _queryChannelsLoadingController.value) {
+          _queryChannelsLoadingController.sink.add(false);
        }
-        _queryChannelsLoadingController.sink.add(false);
      }
-    } catch (err, stackTrace) {
-      print(err);
-      print(stackTrace);
-      _queryChannelsLoadingController.addError(err, stackTrace);
+    } catch (e, stk) {
+      if (_channelsController.hasValue) {
+        _queryChannelsLoadingController.addError(e, stk);
+      } else {
+        _channelsController.addError(e, stk);
+      }
    }
  }

@@ -139,15 +142,14 @@ class ChannelsBlocState extends State<ChannelsBloc>
      _subscriptions.add(client.on(EventType.messageNew).listen((e) {
        final newChannels = List<Channel>.from(channels ?? []);
        final index = newChannels.indexWhere((c) => c.cid == e.cid);
-        if (index > -1) {
+        if (index != -1) {
          if (index > 0) {
            final channel = newChannels.removeAt(index);
            newChannels.insert(0, channel);
          }
-        } else if (widget.shouldAddChannel != null &&
-            widget.shouldAddChannel(e)) {
+        } else if (widget.shouldAddChannel?.call(e) == true) {
          final hiddenIndex = _hiddenChannels.indexWhere((c) => c.cid == e.cid);
-          if (hiddenIndex > -1) {
+          if (hiddenIndex != -1) {
            newChannels.insert(0, _hiddenChannels[hiddenIndex]);
            _hiddenChannels.removeAt(hiddenIndex);
          } else {
@@ -1,8 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';

-// ignore: constant_identifier_names
-enum _LoadingStatus { LOADING, STABLE }
+enum _LoadingStatus { loading, stable }

 /// Wrapper around a [Scrollable] which triggers [onEndOfPage]/[onStartOfPage] the Scrollable
 /// reaches to the start or end of the view extent.
@@ -47,16 +46,16 @@ class LazyLoadScrollView extends StatefulWidget {
 }

 class _LazyLoadScrollViewState extends State<LazyLoadScrollView> {
-  _LoadingStatus _loadMoreStatus = _LoadingStatus.STABLE;
-  double _scrollPosition = 0;
+  _LoadingStatus _loadMoreStatus = _LoadingStatus.stable;

  @override
-  Widget build(BuildContext context) => NotificationListener(
+  Widget build(BuildContext context) =>
+      NotificationListener<ScrollNotification>(
        onNotification: _onNotification,
        child: widget.child,
      );

-  bool _onNotification(Notification notification) {
+  bool _onNotification(ScrollNotification notification) {
    if (notification is ScrollStartNotification) {
      if (widget.onPageScrollStart != null) {
        widget.onPageScrollStart();
@@ -73,7 +72,7 @@ class _LazyLoadScrollViewState extends State<LazyLoadScrollView> {
      final pixels = notification.metrics.pixels;
      final maxScrollExtent = notification.metrics.maxScrollExtent;
      final minScrollExtent = notification.metrics.minScrollExtent;
-      final scrollOffset = widget.scrollOffset;
+      final scrollOffset = widget.scrollOffset ?? 0;

      if (pixels > (minScrollExtent + scrollOffset) &&
          pixels < (maxScrollExtent - scrollOffset)) {
@@ -85,28 +84,15 @@ class _LazyLoadScrollViewState extends State<LazyLoadScrollView> {

      final extentBefore = notification.metrics.extentBefore;
      final extentAfter = notification.metrics.extentAfter;
-      final scrollingDown = _scrollPosition < pixels;

-      if (scrollOffset == null || scrollOffset == 0) {
-        if (extentAfter == 0) {
-          _onEndOfPage();
-        }
-        if (extentBefore == 0) {
-          _onStartOfPage();
-        }
-      } else {
-        if (scrollingDown) {
-          if (extentAfter <= scrollOffset) {
-            _onEndOfPage();
-          }
-        } else {
-          if (extentBefore <= scrollOffset) {
-            _onStartOfPage();
-          }
-        }
+      if (extentAfter <= scrollOffset) {
+        _onEndOfPage();
+        return true;
+      }
+      if (extentBefore <= scrollOffset) {
+        _onStartOfPage();
+        return true;
      }
-      _scrollPosition = pixels;
-      return true;
    }
    if (notification is OverscrollNotification) {
      if (notification.overscroll > 0) {
@@ -121,22 +107,22 @@ class _LazyLoadScrollViewState extends State<LazyLoadScrollView> {
  }

  void _onEndOfPage() {
-    if (_loadMoreStatus != null && _loadMoreStatus == _LoadingStatus.STABLE) {
-      _loadMoreStatus = _LoadingStatus.LOADING;
+    if (_loadMoreStatus != null && _loadMoreStatus == _LoadingStatus.stable) {
+      _loadMoreStatus = _LoadingStatus.loading;
      if (widget.onEndOfPage != null) {
        widget.onEndOfPage().whenComplete(() {
-          _loadMoreStatus = _LoadingStatus.STABLE;
+          _loadMoreStatus = _LoadingStatus.stable;
        });
      }
    }
  }

  void _onStartOfPage() {
-    if (_loadMoreStatus != null && _loadMoreStatus == _LoadingStatus.STABLE) {
-      _loadMoreStatus = _LoadingStatus.LOADING;
+    if (_loadMoreStatus != null && _loadMoreStatus == _LoadingStatus.stable) {
+      _loadMoreStatus = _LoadingStatus.loading;
      if (widget.onStartOfPage != null) {
        widget.onStartOfPage().whenComplete(() {
-          _loadMoreStatus = _LoadingStatus.STABLE;
+          _loadMoreStatus = _LoadingStatus.stable;
        });
      }
    }
@@ -114,28 +114,28 @@ class MessageListCore extends StatefulWidget {
  final bool Function(Message) messageFilter;

  @override
-  _MessageListCoreState createState() => _MessageListCoreState();
+  MessageListCoreState createState() => MessageListCoreState();
 }

-class _MessageListCoreState extends State<MessageListCore> {
-  StreamChannelState streamChannel;
+/// The current state of the [MessageListCore].
+class MessageListCoreState extends State<MessageListCore> {
+  StreamChannelState _streamChannel;

-  bool get _upToDate => streamChannel.channel.state.isUpToDate;
+  bool get _upToDate => _streamChannel.channel.state.isUpToDate;

  bool get _isThreadConversation => widget.parentMessage != null;

-  OwnUser get _currentUser => streamChannel.channel.client.state.user;
+  OwnUser get _currentUser => _streamChannel.channel.client.state.user;

-  List<Message> messages = <Message>[];
-  bool initialMessageHighlightComplete = false;
+  var _messages = <Message>[];

  @override
  Widget build(BuildContext context) {
    final messagesStream = _isThreadConversation
-        ? streamChannel.channel.state.threadsStream
+        ? _streamChannel.channel.state.threadsStream
            .where((threads) => threads.containsKey(widget.parentMessage.id))
            .map((threads) => threads[widget.parentMessage.id])
-        : streamChannel.channel.state?.messagesStream;
+        : _streamChannel.channel.state?.messagesStream;

    bool defaultFilter(Message m) {
      final isMyMessage = m.user.id == _currentUser.id;
@@ -148,10 +148,10 @@ class _MessageListCoreState extends State<MessageListCore> {
      stream: messagesStream?.map((messages) =>
          messages?.where(widget.messageFilter ?? defaultFilter)?.toList()),
      builder: (context, snapshot) {
-        if (!snapshot.hasData) {
-          return widget.loadingBuilder(context);
-        } else if (snapshot.hasError) {
+        if (snapshot.hasError) {
          return widget.errorWidgetBuilder(context, snapshot.error);
+        } else if (!snapshot.hasData) {
+          return widget.loadingBuilder(context);
        } else {
          final messageList = snapshot.data?.reversed?.toList() ?? [];
          if (messageList.isEmpty && !_isThreadConversation) {
@@ -159,29 +159,32 @@ class _MessageListCoreState extends State<MessageListCore> {
              return widget.emptyBuilder(context);
            }
          } else {
-            messages = messageList;
+            _messages = messageList;
          }
-          return widget.messageListBuilder(context, messages);
+          return widget.messageListBuilder(context, _messages);
        }
      },
    );
  }

+  /// Fetches more messages with updated pagination and updates the widget.
+  ///
+  /// Optionally pass the fetch direction, defaults to [QueryDirection.bottom]
  Future<void> paginateData(
      {QueryDirection direction = QueryDirection.bottom}) {
    if (!_isThreadConversation) {
-      return streamChannel.queryMessages(direction: direction);
+      return _streamChannel.queryMessages(direction: direction);
    } else {
-      return streamChannel.getReplies(widget.parentMessage.id);
+      return _streamChannel.getReplies(widget.parentMessage.id);
    }
  }

  @override
  void initState() {
-    streamChannel = StreamChannel.of(context);
+    _streamChannel = StreamChannel.of(context);

    if (_isThreadConversation) {
-      streamChannel.getReplies(widget.parentMessage.id);
+      _streamChannel.getReplies(widget.parentMessage.id);
    }

    if (widget.messageListController != null) {
@@ -194,7 +197,7 @@ class _MessageListCoreState extends State<MessageListCore> {
  @override
  void dispose() {
    if (!_upToDate) {
-      streamChannel.reloadChannel();
+      _streamChannel.reloadChannel();
    }
    super.dispose();
  }
@@ -203,5 +206,5 @@ class _MessageListCoreState extends State<MessageListCore> {
 /// Controller used for paginating data in [ChannelListView]
 class MessageListController {
  /// Call this function to load further data
-  Function({QueryDirection direction}) paginateData;
+  Future<void> Function({QueryDirection direction}) paginateData;
 }
@@ -48,17 +48,16 @@ class MessageSearchBlocState extends State<MessageSearchBloc>
  Stream<List<GetMessageResponse>> get messagesStream =>
      _messageResponses.stream;

-  final BehaviorSubject<List<GetMessageResponse>> _messageResponses =
-      BehaviorSubject();
+  final _messageResponses = BehaviorSubject<List<GetMessageResponse>>();

-  final BehaviorSubject<bool> _queryMessagesLoadingController =
-      BehaviorSubject.seeded(false);
+  final _queryMessagesLoadingController = BehaviorSubject.seeded(false);

  /// The stream notifying the state of queryUsers call
  Stream<bool> get queryMessagesLoading =>
      _queryMessagesLoadingController.stream;

-  /// Calls [StreamChatClient.search] updating [messageResponses] stream
+  /// Calls [StreamChatClient.search] updating
+  /// [messagesStream] and [queryMessagesLoading] stream
  Future<void> search({
    Map<String, dynamic> filter,
    Map<String, dynamic> messageFilter,
@@ -66,33 +65,13 @@ class MessageSearchBlocState extends State<MessageSearchBloc>
    String query,
    PaginationParams pagination,
  }) async {
-    _messageResponses.add(null);
-    try {
-      final messages = await _search(
-        filter: filter,
-        messageFilter: messageFilter,
-        sort: sort,
-        query: query,
-        pagination: pagination,
-      );
-      _messageResponses.add(messages.results);
-    } catch (err, stk) {
-      _messageResponses.addError(err, stk);
-    }
-  }
+    final client = StreamChatCore.of(context).client;

-  /// Calls [StreamChatClient.search] updating [queryMessagesLoading] stream
-  Future<void> loadMore({
-    Map<String, dynamic> filter,
-    Map<String, dynamic> messageFilter,
-    List<SortOption> sort,
-    String query,
-    PaginationParams pagination,
-  }) async {
-    if (_queryMessagesLoadingController.value == true) {
-      return;
+    if (_queryMessagesLoadingController.value == true) return;
+
+    if (_messageResponses.hasValue) {
+      _queryMessagesLoadingController.add(true);
    }
-    _queryMessagesLoadingController.add(true);
    try {
      final clear = pagination == null ||
          pagination.offset == null ||
@@ -100,12 +79,12 @@ class MessageSearchBlocState extends State<MessageSearchBloc>

      final oldMessages = List<GetMessageResponse>.from(messageResponses ?? []);

-      final messages = await _search(
-        filter: filter,
-        messageFilter: messageFilter,
+      final messages = await client.search(
+        filter,
        sort: sort,
        query: query,
-        pagination: pagination,
+        paginationParams: pagination,
+        messageFilters: messageFilter,
      );

      if (clear) {
@@ -114,30 +93,18 @@ class MessageSearchBlocState extends State<MessageSearchBloc>
        final temp = oldMessages + messages.results;
        _messageResponses.add(temp);
      }
-
-      _queryMessagesLoadingController.add(false);
-    } catch (err, stackTrace) {
-      _queryMessagesLoadingController.addError(err, stackTrace);
+      if (_messageResponses.hasValue && _queryMessagesLoadingController.value) {
+        _queryMessagesLoadingController.add(false);
+      }
+    } catch (e, stk) {
+      if (_messageResponses.hasValue) {
+        _queryMessagesLoadingController.addError(e, stk);
+      } else {
+        _messageResponses.addError(e, stk);
+      }
    }
  }

-  Future<SearchMessagesResponse> _search({
-    Map<String, dynamic> filter,
-    Map<String, dynamic> messageFilter,
-    List<SortOption> sort,
-    String query,
-    PaginationParams pagination,
-  }) {
-    final client = StreamChatCore.of(context).client;
-    return client.search(
-      filter,
-      sort: sort,
-      query: query,
-      paginationParams: pagination,
-      messageFilters: messageFilter,
-    );
-  }
-
  @override
  Widget build(BuildContext context) {
    super.build(context);
@@ -104,21 +104,15 @@ class MessageSearchListCore extends StatefulWidget {
  final WidgetBuilder loadingBuilder;

  @override
-  _MessageSearchListCoreState createState() => _MessageSearchListCoreState();
+  MessageSearchListCoreState createState() => MessageSearchListCoreState();
 }

-class _MessageSearchListCoreState extends State<MessageSearchListCore> {
+/// The current state of the [MessageSearchListCore].
+class MessageSearchListCoreState extends State<MessageSearchListCore> {
  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
-    MessageSearchBloc.of(context).search(
-      filter: widget.filters,
-      sort: widget.sortOptions,
-      query: widget.messageQuery,
-      pagination: widget.paginationParams,
-      messageFilter: widget.messageFilters,
-    );
-
+    loadData();
    if (widget.messageSearchListController != null) {
      widget.messageSearchListController.loadData = loadData;
      widget.messageSearchListController.paginateData = paginateData;
@@ -136,29 +130,23 @@ class _MessageSearchListCoreState extends State<MessageSearchListCore> {
        stream: messageSearchBloc.messagesStream,
        builder: (context, snapshot) {
          if (snapshot.hasError) {
-            if (snapshot.error is Error) {
-              print((snapshot.error as Error).stackTrace);
-            }
-
            return widget.errorBuilder(context, snapshot.error);
          }
-
          if (!snapshot.hasData) {
            return widget.loadingBuilder(context);
          }
-
          final items = snapshot.data;
-
          if (items.isEmpty) {
            return widget.emptyBuilder(context);
          }
-
          return widget.childBuilder(snapshot.data);
        },
      );

-  void loadData() {
-    MessageSearchBloc.of(context).search(
+  /// Fetches initial messages and updates the widget
+  Future<void> loadData() {
+    final messageSearchBloc = MessageSearchBloc.of(context);
+    return messageSearchBloc.search(
      filter: widget.filters,
      sort: widget.sortOptions,
      query: widget.messageQuery,
@@ -167,10 +155,10 @@ class _MessageSearchListCoreState extends State<MessageSearchListCore> {
    );
  }

-  void paginateData() {
+  /// Fetches more messages with updated pagination and updates the widget
+  Future<void> paginateData() {
    final messageSearchBloc = MessageSearchBloc.of(context);
-
-    messageSearchBloc.loadMore(
+    return messageSearchBloc.search(
      filter: widget.filters,
      sort: widget.sortOptions,
      pagination: widget.paginationParams.copyWith(
@@ -186,18 +174,12 @@ class _MessageSearchListCoreState extends State<MessageSearchListCore> {
    super.didUpdateWidget(oldWidget);
    if (widget.filters?.toString() != oldWidget.filters?.toString() ||
        jsonEncode(widget.sortOptions) != jsonEncode(oldWidget.sortOptions) ||
-        widget.paginationParams?.toJson()?.toString() !=
-            oldWidget.paginationParams?.toJson()?.toString() ||
        widget.messageQuery?.toString() != oldWidget.messageQuery?.toString() ||
        widget.messageFilters?.toString() !=
-            oldWidget.messageFilters?.toString()) {
-      MessageSearchBloc.of(context).search(
-        filter: widget.filters,
-        sort: widget.sortOptions,
-        query: widget.messageQuery,
-        pagination: widget.paginationParams,
-        messageFilter: widget.messageFilters,
-      );
+            oldWidget.messageFilters?.toString() ||
+        widget.paginationParams?.toJson()?.toString() !=
+            oldWidget.paginationParams?.toJson()?.toString()) {
+      loadData();
    }
  }
 }
@@ -205,8 +187,8 @@ class _MessageSearchListCoreState extends State<MessageSearchListCore> {
 /// Controller used for paginating data in [ChannelListView]
 class MessageSearchListController {
  /// Call this function to reload data
-  VoidCallback loadData;
+  AsyncCallback loadData;

  /// Call this function to load further data
-  VoidCallback paginateData;
+  AsyncCallback paginateData;
 }
@@ -207,15 +207,14 @@ class StreamChannelState extends State<StreamChannel> {
    int after = 20,
    bool preferOffline = false,
  }) =>
-      queryAtMessage(
+      _queryAtMessage(
        messageId: messageId,
        before: before,
        after: after,
        preferOffline: preferOffline,
      );

-  ///
-  Future<void> queryAtMessage({
+  Future<void> _queryAtMessage({
    String messageId,
    int before = 20,
    int after = 20,
@@ -297,7 +296,7 @@ class StreamChannelState extends State<StreamChannel> {
  }

  /// Reloads the channel with latest message
-  Future<void> reloadChannel() => queryAtMessage(before: 30);
+  Future<void> reloadChannel() => _queryAtMessage(before: 30);

  List<Future<bool>> _futures;

@@ -305,8 +304,7 @@ class StreamChannelState extends State<StreamChannel> {
    try {
      await loadChannelAtMessage(initialMessageId);
      return true;
-    } catch (e, stk) {
-      print('Error: $e\nStack: $stk');
+    } catch (_) {
      rethrow;
    }
  }
@@ -349,9 +347,6 @@ class StreamChannelState extends State<StreamChannel> {
      ],
      builder: (context, snapshot) {
        if (snapshot.hasError) {
-          if (snapshot.error is Error) {
-            print((snapshot.error as Error).stackTrace);
-          }
          var message = snapshot.error.toString();
          if (snapshot.error is DioError) {
            final dioError = snapshot.error as DioError;
@@ -361,9 +356,7 @@ class StreamChannelState extends State<StreamChannel> {
              message = 'Check your connection and retry';
            }
          }
-          return Center(
-            child: Text(message),
-          );
+          return Center(child: Text(message));
        }
        final initialized = snapshot.data[0];
        // ignore: avoid_bool_literals_in_conditional_expressions
@@ -93,10 +93,10 @@ class StreamChatCoreState extends State<StreamChatCore>
  Widget build(BuildContext context) => widget.child;

  /// The current user
-  User get user => widget.client.state.user;
+  User get user => client.state?.user;

  /// The current user as a stream
-  Stream<User> get userStream => widget.client.state.userStream;
+  Stream<User> get userStream => client.state?.userStream;

  @override
  void initState() {
@@ -108,21 +108,25 @@ class StreamChatCoreState extends State<StreamChatCore>

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
-    if (client.state?.user != null) {
+    if (user != null) {
      if (state == AppLifecycleState.paused) {
-        if (widget.onBackgroundEventReceived != null) {
-          _eventSubscription =
-              client.on().listen(widget.onBackgroundEventReceived);
-          _disconnectTimer = Timer(
-            widget.backgroundKeepAlive,
-            client.disconnect,
-          );
-        } else {
+        if (widget.onBackgroundEventReceived == null) {
+          client.disconnect();
+          return;
+        }
+        _eventSubscription = client.on().listen(
+              widget.onBackgroundEventReceived,
+            );
+
+        void onTimerComplete() {
+          _eventSubscription.cancel();
          client.disconnect();
        }
+
+        _disconnectTimer = Timer(widget.backgroundKeepAlive, onTimerComplete);
      } else if (state == AppLifecycleState.resumed) {
-        _eventSubscription?.cancel();
        if (_disconnectTimer?.isActive == true) {
+          _eventSubscription.cancel();
          _disconnectTimer.cancel();
        } else {
          if (client.wsConnectionStatus == ConnectionStatus.disconnected) {
@@ -80,7 +80,7 @@ class UserListCore extends StatefulWidget {
  final UserListController userListController;

  /// The builder that will be used in case of error
-  final Widget Function(Error error) errorBuilder;
+  final Widget Function(Object error) errorBuilder;

  /// The builder that will be used to build the list
  final Widget Function(BuildContext context, List<ListItem> users) listBuilder;
@@ -120,21 +120,16 @@ class UserListCore extends StatefulWidget {
  final bool groupAlphabetically;

  @override
-  _UserListCoreState createState() => _UserListCoreState();
+  UserListCoreState createState() => UserListCoreState();
 }

-class _UserListCoreState extends State<UserListCore>
+/// The current state of the [UserListCore].
+class UserListCoreState extends State<UserListCore>
    with WidgetsBindingObserver {
  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
-    UsersBloc.of(context).queryUsers(
-      filter: widget.filter,
-      sort: widget.sort,
-      pagination: widget.pagination,
-      options: widget.options,
-    );
-
+    loadData();
    if (widget.userListController != null) {
      widget.userListController.loadData = loadData;
      widget.userListController.paginateData = paginateData;
@@ -144,11 +139,10 @@ class _UserListCoreState extends State<UserListCore>
  @override
  Widget build(BuildContext context) {
    final _usersBloc = UsersBloc.of(context);
-
    return _buildListView(_usersBloc);
  }

-  bool get isListAlreadySorted =>
+  bool get _isListAlreadySorted =>
      widget.sort?.any((e) => e.field == 'name' && e.direction == 1) ?? false;

  Stream<List<ListItem>> _buildUserStream(
@@ -158,7 +152,7 @@ class _UserListCoreState extends State<UserListCore>
        (users) {
          if (widget.groupAlphabetically) {
            var temp = users;
-            if (!isListAlreadySorted) {
+            if (!_isListAlreadySorted) {
              temp = users
                ..sort((curr, next) => curr.name.compareTo(next.name));
            }
@@ -186,33 +180,23 @@ class _UserListCoreState extends State<UserListCore>
        stream: _buildUserStream(usersBlocState),
        builder: (context, snapshot) {
          if (snapshot.hasError) {
-            if (snapshot.error is Error) {
-              print((snapshot.error as Error).stackTrace);
-            }
-
            return widget.errorBuilder(snapshot.error);
          }
-
          if (!snapshot.hasData) {
            return widget.loadingBuilder(context);
          }
-
          final items = snapshot.data;
-
          if (items.isEmpty) {
            return widget.emptyBuilder(context);
          }
-
-          if (items.isEmpty) {
-            return widget.emptyBuilder(context);
-          }
-
          return widget.listBuilder(context, items);
        },
      );

-  void loadData() {
-    UsersBloc.of(context).queryUsers(
+  // ignore: public_member_api_docs
+  Future<void> loadData() {
+    final _usersBloc = UsersBloc.of(context);
+    return _usersBloc.queryUsers(
      filter: widget.filter,
      sort: widget.sort,
      pagination: widget.pagination,
@@ -220,10 +204,10 @@ class _UserListCoreState extends State<UserListCore>
    );
  }

-  void paginateData() {
+  // ignore: public_member_api_docs
+  Future<void> paginateData() {
    final _usersBloc = UsersBloc.of(context);
-
-    _usersBloc.queryUsers(
+    return _usersBloc.queryUsers(
      filter: widget.filter,
      sort: widget.sort,
      pagination: widget.pagination.copyWith(
@@ -238,15 +222,10 @@ class _UserListCoreState extends State<UserListCore>
    super.didUpdateWidget(oldWidget);
    if (widget.filter?.toString() != oldWidget.filter?.toString() ||
        jsonEncode(widget.sort) != jsonEncode(oldWidget.sort) ||
+        widget.options?.toString() != oldWidget.options?.toString() ||
        widget.pagination?.toJson()?.toString() !=
-            oldWidget.pagination?.toJson()?.toString() ||
-        widget.options?.toString() != oldWidget.options?.toString()) {
-      UsersBloc.of(context).queryUsers(
-        filter: widget.filter,
-        sort: widget.sort,
-        pagination: widget.pagination,
-        options: widget.options,
-      );
+            oldWidget.pagination?.toJson()?.toString()) {
+      loadData();
    }
  }
 }
@@ -255,11 +234,11 @@ class _UserListCoreState extends State<UserListCore>
 /// Header items are prefixed with the key `HEADER` While users are prefixed
 /// with `USER`.
 abstract class ListItem {
-  // ignore: public_member_api_docs
+  /// Unique key per list item
  String get key {
    if (this is ListHeaderItem) {
      final header = (this as ListHeaderItem).heading;
-      return 'HEADER-$header';
+      return 'HEADER-${header.toLowerCase()}';
    }
    if (this is ListUserItem) {
      final user = (this as ListUserItem).user;
@@ -268,7 +247,8 @@ abstract class ListItem {
    return null;
  }

-  // ignore: public_member_api_docs
+  /// Helper function to build widget based on ListItem type
+  // ignore: missing_return
  Widget when({
    @required Widget Function(String heading) headerItem,
    @required Widget Function(User user) userItem,
@@ -279,33 +259,32 @@ abstract class ListItem {
    if (this is ListUserItem) {
      return userItem((this as ListUserItem).user);
    }
-    return const SizedBox();
  }
 }

-// ignore: public_member_api_docs
+/// Header Item
 class ListHeaderItem extends ListItem {
-  // ignore: public_member_api_docs
+  /// Constructs a new [ListHeaderItem]
  ListHeaderItem(this.heading);

-  // ignore: public_member_api_docs
+  /// Heading used to build the item.
  final String heading;
 }

-// ignore: public_member_api_docs
+/// User Item
 class ListUserItem extends ListItem {
-  // ignore: public_member_api_docs
+  /// Constructs a new [ListUserItem]
  ListUserItem(this.user);

-  // ignore: public_member_api_docs
+  /// [User] used to build the item.
  final User user;
 }

 /// Controller used for paginating data in [ChannelListView]
 class UserListController {
  /// Call this function to reload data
-  VoidCallback loadData;
+  AsyncCallback loadData;

  /// Call this function to load further data
-  VoidCallback paginateData;
+  AsyncCallback paginateData;
 }
@@ -51,10 +51,9 @@ class UsersBlocState extends State<UsersBloc>
  /// The current users list as a stream
  Stream<List<User>> get usersStream => _usersController.stream;

-  final BehaviorSubject<List<User>> _usersController = BehaviorSubject();
+  final _usersController = BehaviorSubject<List<User>>();

-  final BehaviorSubject<bool> _queryUsersLoadingController =
-      BehaviorSubject.seeded(false);
+  final _queryUsersLoadingController = BehaviorSubject.seeded(false);

  /// The stream notifying the state of queryUsers call
  Stream<bool> get queryUsersLoading => _queryUsersLoadingController.stream;
@@ -70,11 +69,12 @@ class UsersBlocState extends State<UsersBloc>
  }) async {
    final client = StreamChatCore.of(context).client;

-    if (client.state?.user == null ||
-        _queryUsersLoadingController.value == true) {
-      return;
+    if (_queryUsersLoadingController.value == true) return;
+
+    if (_usersController.hasValue) {
+      _queryUsersLoadingController.add(true);
    }
-    _queryUsersLoadingController.add(true);
+
    try {
      final clear = pagination == null ||
          pagination.offset == null ||
@@ -95,10 +95,15 @@ class UsersBlocState extends State<UsersBloc>
        final temp = oldUsers + usersResponse.users;
        _usersController.add(temp);
      }
-
-      _queryUsersLoadingController.add(false);
-    } catch (err, stackTrace) {
-      _queryUsersLoadingController.addError(err, stackTrace);
+      if (_usersController.hasValue && _queryUsersLoadingController.value) {
+        _queryUsersLoadingController.add(false);
+      }
+    } catch (e, stk) {
+      if (_usersController.hasValue) {
+        _queryUsersLoadingController.addError(e, stk);
+      } else {
+        _usersController.addError(e, stk);
+      }
    }
  }

@@ -2,14 +2,14 @@ library stream_chat_flutter_core;

 export 'package:stream_chat/stream_chat.dart';

-export 'src/channel_list_core.dart';
+export 'src/channel_list_core.dart' hide ChannelListCoreState;
 export 'src/channels_bloc.dart';
 export 'src/lazy_load_scroll_view.dart';
-export 'src/message_list_core.dart';
+export 'src/message_list_core.dart' hide MessageListCoreState;
 export 'src/message_search_bloc.dart';
-export 'src/message_search_list_core.dart';
+export 'src/message_search_list_core.dart' hide MessageSearchListCoreState;
 export 'src/stream_channel.dart';
 export 'src/stream_chat_core.dart';
 export 'src/typedef.dart';
-export 'src/user_list_core.dart';
+export 'src/user_list_core.dart' hide UserListCoreState;
 export 'src/users_bloc.dart';