use random pngs

lib/src/stream_chat_theme.dart

@@ -1,3 +1,4 @@
+import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:stream_chat/stream_chat.dart';
 import 'package:stream_chat_flutter/src/channel_header.dart';
@@ -5,6 +6,7 @@ import 'package:stream_chat_flutter/src/channel_preview.dart';
 import 'package:stream_chat_flutter/src/message_input.dart';
 import 'package:stream_chat_flutter/src/reaction_icon.dart';
 import 'package:stream_chat_flutter/src/stream_icons.dart';
+import 'package:stream_chat_flutter/src/utils.dart';
 
 /// Inherited widget providing the [StreamChatThemeData] to the widget tree
 class StreamChatTheme extends InheritedWidget {
@@ -226,9 +228,9 @@ class StreamChatThemeData {
       defaultChannelImage: (context, channel) => SizedBox(),
       backgroundColor: isDark ? Colors.black : Colors.white,
       defaultUserImage: (context, user) => Center(
-        child: Text(
-          user.name?.substring(0, 1) ?? '',
-          style: TextStyle(color: Colors.white),
+        child: CachedNetworkImage(
+          imageUrl: getRandomPicUrl(user),
+          fit: BoxFit.cover,
         ),
       ),
       channelPreviewTheme: ChannelPreviewTheme(

lib/src/user_avatar.dart

@@ -27,6 +27,7 @@ class UserAvatar extends StatelessWidget {
     final hasImage = user.extraData?.containsKey('image') == true &&
         user.extraData['image'] != null &&
         user.extraData['image'] != '';
+    final streamChatTheme = StreamChatTheme.of(context);
     return GestureDetector(
       onTap: onTap != null
           ? () {
@@ -39,36 +40,22 @@ class UserAvatar extends StatelessWidget {
         children: <Widget>[
           ClipRRect(
             borderRadius: borderRadius ??
-                StreamChatTheme.of(context)
-                    .ownMessageTheme
-                    .avatarTheme
-                    .borderRadius,
+                streamChatTheme.ownMessageTheme.avatarTheme.borderRadius,
             child: Container(
               constraints: constraints ??
-                  StreamChatTheme.of(context)
-                      .ownMessageTheme
-                      .avatarTheme
-                      .constraints,
+                  streamChatTheme.ownMessageTheme.avatarTheme.constraints,
               decoration: BoxDecoration(
-                color: StreamChatTheme.of(context).accentColor,
+                color: streamChatTheme.accentColor,
               ),
               child: hasImage
                   ? CachedNetworkImage(
                       imageUrl: user.extraData['image'],
                       errorWidget: (_, __, ___) {
-                        return Center(
-                          child: Text(
-                            user.name[0],
-                            style: TextStyle(
-                              color: Colors.white,
-                              fontWeight: FontWeight.bold,
-                            ),
-                          ),
-                        );
+                        return streamChatTheme.defaultUserImage(context, user);
                       },
                       fit: BoxFit.cover,
                     )
-                  : StreamChatTheme.of(context).defaultUserImage(context, user),
+                  : streamChatTheme.defaultUserImage(context, user),
             ),
           ),
           if (showOnlineStatus && user.online == true)

lib/src/utils.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:stream_chat/stream_chat.dart';
 import 'package:url_launcher/url_launcher.dart';
 
 Future<void> launchURL(BuildContext context, String url) async {
@@ -42,3 +43,7 @@ Future<bool> showConfirmationDialog(
     },
   );
 }
+
+/// Get random png with initials
+String getRandomPicUrl(User user) =>
+    'https://getstream.io/random_png/?id=${user.id}&name=${user.name}';