add channel muted ui

lib/src/channel_preview.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
 import 'package:jiffy/jiffy.dart';
+import 'package:line_awesome_icons/line_awesome_icons.dart';
 import 'package:stream_chat/stream_chat.dart';
 import 'package:stream_chat_flutter/src/unread_indicator.dart';
 
@@ -42,7 +43,9 @@ class ChannelPreview extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return ListTile(
+    return Opacity(
+      opacity: channel.isMuted ? 0.5 : 1,
+      child: ListTile(
         onTap: () {
           if (onTap != null) {
             onTap(channel);
@@ -61,7 +64,8 @@ class ChannelPreview extends StatelessWidget {
           children: <Widget>[
             Flexible(
               child: ChannelName(
-              textStyle: StreamChatTheme.of(context).channelPreviewTheme.title,
+                textStyle:
+                    StreamChatTheme.of(context).channelPreviewTheme.title,
               ),
             ),
             if (channel.state.unreadCount > 0)
@@ -96,6 +100,7 @@ class ChannelPreview extends StatelessWidget {
             _buildDate(context),
           ],
         ),
+      ),
     );
   }
 
@@ -129,15 +134,35 @@ class ChannelPreview extends StatelessWidget {
   }
 
   Widget _buildSubtitle(BuildContext context) {
+    if (channel.isMuted) {
+      return Row(
+        crossAxisAlignment: CrossAxisAlignment.end,
+        children: <Widget>[
+          Icon(
+            LineAwesomeIcons.volume_off,
+            size: 15,
+          ),
+          Text(
+            'Channel is muted',
+            style: StreamChatTheme.of(context)
+                .channelPreviewTheme
+                .subtitle
+                .copyWith(
+                  color: StreamChatTheme.of(context)
+                      .channelPreviewTheme
+                      .subtitle
+                      .color,
+                ),
+          ),
+        ],
+      );
+    }
     return TypingIndicator(
       channel: channel,
       alternativeWidget: _buildLastMessage(context),
       style: StreamChatTheme.of(context).channelPreviewTheme.subtitle.copyWith(
-            color: StreamChatTheme.of(context)
-                .channelPreviewTheme
-                .subtitle
-                .color
-                .withOpacity(0.5),
+            color:
+                StreamChatTheme.of(context).channelPreviewTheme.subtitle.color,
           ),
     );
   }
@@ -186,8 +211,7 @@ class ChannelPreview extends StatelessWidget {
                     color: StreamChatTheme.of(context)
                         .channelPreviewTheme
                         .subtitle
-                        .color
-                        .withOpacity(0.5),
+                        .color,
                     fontStyle: (lastMessage.isSystem || lastMessage.isDeleted)
                         ? FontStyle.italic
                         : FontStyle.normal,

lib/src/stream_chat_theme.dart

@@ -231,7 +231,7 @@ class StreamChatThemeData {
         ),
         subtitle: TextStyle(
           fontSize: 12.5,
-          color: isDark ? Colors.white : Colors.black,
+          color: (isDark ? Colors.white : Colors.black).withOpacity(0.5),
         ),
         lastMessageAt: TextStyle(
           fontSize: 11,