fix thread unread indicator

lib/src/back_button.dart

@@ -9,11 +9,15 @@ class StreamBackButton extends StatelessWidget {
     Key key,
     this.onPressed,
     this.showUnreads = false,
+    this.cid,
   }) : super(key: key);
 
   final VoidCallback onPressed;
   final bool showUnreads;
 
+  /// Channel cid used to retrieve unread count
+  final String cid;
+
   @override
   Widget build(BuildContext context) {
     return Stack(
@@ -45,7 +49,9 @@ class StreamBackButton extends StatelessWidget {
           Positioned(
             top: 7,
             right: 7,
-            child: UnreadIndicator(),
+            child: UnreadIndicator(
+              cid: cid,
+            ),
           ),
       ],
     );

lib/src/message_list_view.dart

@@ -187,7 +187,6 @@ class MessageListView extends StatefulWidget {
 
 class _MessageListViewState extends State<MessageListView> {
   ItemScrollController _scrollController;
-  bool _bottomWasVisible = false;
   Function _onThreadTap;
   bool _showScrollToBottom = false;
   ItemPositionsListener _itemPositionListener;
@@ -692,14 +691,13 @@ class _MessageListViewState extends State<MessageListView> {
       key: ValueKey<String>('BOTTOM-MESSAGE'),
       onVisibilityChanged: (visibility) {
         final isVisible = visibility.visibleBounds != Rect.zero;
-        if (isVisible && !_bottomWasVisible) {
+        if (isVisible) {
           final channel = streamChannel.channel;
           if (_upToDate &&
               channel.config?.readEvents == true &&
               channel.state.unreadCount > 0) {
             streamChannel.channel.markRead();
           }
-          _bottomWasVisible = !isVisible;
         }
         if (mounted) {
           setState(() => _showScrollToBottom = !isVisible);

lib/src/thread_header.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:stream_chat/stream_chat.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
+import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 import 'back_button.dart';
 import 'channel_name.dart';
@@ -81,6 +82,7 @@ class ThreadHeader extends StatelessWidget implements PreferredSizeWidget {
       elevation: 1,
       leading: showBackButton
           ? StreamBackButton(
+              cid: StreamChannel.of(context).channel.cid,
               onPressed: onBackPressed,
               showUnreads: true,
             )

lib/src/unread_indicator.dart

@@ -5,14 +5,22 @@ import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 class UnreadIndicator extends StatelessWidget {
   const UnreadIndicator({
     Key key,
+    this.cid,
   }) : super(key: key);
 
+  /// Channel cid used to retrieve unread count
+  final String cid;
+
   @override
   Widget build(BuildContext context) {
     final client = StreamChat.of(context).client;
     return StreamBuilder<int>(
-      stream: client.state.totalUnreadCountStream,
-      initialData: client.state.totalUnreadCount,
+      stream: cid != null
+          ? client.state.channels[cid].state.unreadCountStream
+          : client.state.totalUnreadCountStream,
+      initialData: cid != null
+          ? client.state.channels[cid].state.unreadCount
+          : client.state.totalUnreadCount,
       builder: (context, snapshot) {
         if (!snapshot.hasData || snapshot.data == 0) {
           return SizedBox();