add unread indicator in backbutton

lib/src/back_button.dart

@@ -1,21 +1,29 @@
 import 'package:flutter/material.dart';
+import 'package:stream_chat_flutter/src/stream_icons.dart';
+import 'package:stream_chat_flutter/src/unread_indicator.dart';
+import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
 class StreamBackButton extends StatelessWidget {
   const StreamBackButton({
     Key key,
     this.onPressed,
     this.icon = Icons.arrow_back_ios_outlined,
+    this.showUnreads = false,
   }) : super(key: key);
 
   final VoidCallback onPressed;
   final IconData icon;
+  final bool showUnreads;
 
   @override
   Widget build(BuildContext context) {
-    return Padding(
+    return Stack(
+      children: [
+        Padding(
           padding: const EdgeInsets.all(14.0),
           child: RawMaterialButton(
-        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(4)),
+            shape:
+                RoundedRectangleBorder(borderRadius: BorderRadius.circular(4)),
             elevation: 0,
             highlightElevation: 0,
             focusElevation: 0,
@@ -28,17 +36,22 @@ class StreamBackButton extends StatelessWidget {
                 Navigator.of(context).pop();
               }
             },
-        fillColor: Theme.of(context).brightness == Brightness.dark
-            ? Colors.white.withOpacity(.1)
-            : Colors.black.withOpacity(.1),
             child: Icon(
-          icon ?? Icons.arrow_back_ios_outlined,
+              icon ?? StreamIcons.left,
-          size: 15,
+              size: 24,
               color: Theme.of(context).brightness == Brightness.dark
                   ? Colors.white
                   : Colors.black,
             ),
           ),
+        ),
+        if (showUnreads)
+          Positioned(
+            top: 7,
+            right: 7,
+            child: UnreadIndicator(),
+          ),
+      ],
     );
   }
 }

lib/src/channel_header.dart

@@ -81,7 +81,10 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
       brightness: Theme.of(context).brightness,
       elevation: 1,
       leading: showBackButton
-          ? StreamBackButton(onPressed: onBackPressed)
+          ? StreamBackButton(
+              onPressed: onBackPressed,
+              showUnreads: true,
+            )
           : SizedBox(),
       backgroundColor:
           StreamChatTheme.of(context).channelTheme.channelHeaderTheme.color,

lib/src/channel_preview.dart

@@ -2,10 +2,10 @@ import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:jiffy/jiffy.dart';
 import 'package:stream_chat/stream_chat.dart';
-import 'package:stream_chat_flutter/src/unread_indicator.dart';
 
 import '../stream_chat_flutter.dart';
 import 'channel_name.dart';
+import 'channel_unread_indicator.dart';
 
 /// ![screenshot](https://raw.githubusercontent.com/GetStream/stream-chat-flutter/master/screenshots/channel_preview.png)
 /// ![screenshot](https://raw.githubusercontent.com/GetStream/stream-chat-flutter/master/screenshots/channel_preview_paint.png)
@@ -80,7 +80,7 @@ class ChannelPreview extends StatelessWidget {
                                 e.user.id == channel.client.state.user.id)) {
                           return SizedBox();
                         }
-                        return UnreadIndicator(
+                        return ChannelUnreadIndicator(
                           channel: channel,
                         );
                       }),

lib/src/channel_unread_indicator.dart

@@ -0,0 +1,48 @@
+import 'package:flutter/material.dart';
+import 'package:stream_chat/stream_chat.dart';
+import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
+
+class ChannelUnreadIndicator extends StatelessWidget {
+  const ChannelUnreadIndicator({
+    Key key,
+    @required this.channel,
+  }) : super(key: key);
+
+  final Channel channel;
+
+  @override
+  Widget build(BuildContext context) {
+    return StreamBuilder<int>(
+      stream: channel.state.unreadCountStream,
+      initialData: channel.state.unreadCount,
+      builder: (context, snapshot) {
+        if (!snapshot.hasData || snapshot.data == 0) {
+          return SizedBox();
+        }
+        return Material(
+          borderRadius: BorderRadius.circular(8),
+          color: StreamChatTheme.of(context)
+              .channelPreviewTheme
+              .unreadCounterColor,
+          child: Padding(
+            padding: const EdgeInsets.only(
+              left: 5.0,
+              right: 5.0,
+              top: 2,
+              bottom: 1,
+            ),
+            child: Center(
+              child: Text(
+                '${snapshot.data}',
+                style: TextStyle(
+                  fontSize: 11,
+                  color: Colors.white,
+                ),
+              ),
+            ),
+          ),
+        );
+      },
+    );
+  }
+}

lib/src/unread_indicator.dart

@@ -1,20 +1,18 @@
 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';
 
 class UnreadIndicator extends StatelessWidget {
   const UnreadIndicator({
     Key key,
-    @required this.channel,
   }) : super(key: key);
 
-  final Channel channel;
-
   @override
   Widget build(BuildContext context) {
+    final client = StreamChat.of(context).client;
     return StreamBuilder<int>(
-        stream: channel.state.unreadCountStream,
+      stream: client.state.totalUnreadCountStream,
-        initialData: channel.state.unreadCount,
+      initialData: client.state.totalUnreadCount,
       builder: (context, snapshot) {
         if (!snapshot.hasData || snapshot.data == 0) {
           return SizedBox();
@@ -42,6 +40,7 @@ class UnreadIndicator extends StatelessWidget {
             ),
           ),
         );
-        });
+      },
+    );
   }
 }