Merge pull request #1213 from GetStream/feature/openToUnread

feat(ui): open message list to unread position

packages/stream_chat_flutter/CHANGELOG.md

@@ -16,6 +16,7 @@
   color of pinned messages.
 - Added unread messages divider in `StreamMessageListView`.
 - Added `StreamMessageListView.unreadMessagesSeparatorBuilder`.
+- Now `StreamMessageListView` opens to the oldest unread message by default.
 
 ## 4.2.0
 

packages/stream_chat_flutter/lib/src/message_list_view.dart

@@ -387,6 +387,11 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
       if (index != 0) return index + 1;
       return index;
     }
+
+    if (unreadCount > 0) {
+      return unreadCount + 1;
+    }
+
     return 0;
   }
 
@@ -932,6 +937,9 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
     if (unreadCount > 0) {
       streamChannel!.channel.markRead();
     }
+
+    final index = unreadCount > 0 ? unreadCount + 1 : 0;
+
     if (!_upToDate) {
       _bottomPaginationActive = false;
       initialAlignment = 0;
@@ -939,11 +947,11 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
       await streamChannel!.reloadChannel();
 
       WidgetsBinding.instance.addPostFrameCallback((_) {
-        _scrollController!.jumpTo(index: unreadCount);
+        _scrollController!.jumpTo(index: index);
       });
     } else {
       _scrollController!.scrollTo(
-        index: unreadCount,
+        index: index,
         duration: const Duration(seconds: 1),
         curve: Curves.easeInOut,
       );
@@ -1366,6 +1374,8 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
     if (newStreamChannel != streamChannel) {
       streamChannel = newStreamChannel;
       _messageNewListener?.cancel();
+
+      unreadCount = streamChannel?.channel.state?.unreadCount ?? 0;
       initialIndex = _initialIndex;
       initialAlignment = _initialAlignment;
 
@@ -1377,7 +1387,10 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
       }
 
       _messageNewListener =
-          streamChannel!.channel.on(EventType.messageNew).listen((event) {
+          streamChannel!.channel.on(EventType.messageNew).skip(1)
+              //skipping the first event because
+              //the StreamController is a BehaviorSubject
+              .listen((event) {
         if (_upToDate) {
           _bottomPaginationActive = false;
         }