add image on tap

lib/src/channel_header.dart

@@ -57,15 +57,19 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
   /// By default it calls [Navigator.pop]
   final VoidCallback onBackPressed;
 
-  /// Callback to call when pressing the header is tapped.
+  /// Callback to call when the header is tapped.
   final VoidCallback onTitleTap;
 
+  /// Callback to call when the image is tapped.
+  final VoidCallback onImageTap;
+
   /// Creates a channel header
   ChannelHeader({
     Key key,
     this.showBackButton = true,
     this.onBackPressed,
     this.onTitleTap,
+    this.onImageTap,
   })  : preferredSize = Size.fromHeight(kToolbarHeight),
         super(key: key);
 
@@ -80,18 +84,16 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
       actions: <Widget>[
         Padding(
           padding: const EdgeInsets.only(right: 10.0),
-          child: Stack(
-            children: <Widget>[
-              Center(
-                child: ChannelImage(),
-              ),
-            ],
+          child: Center(
+            child: ChannelImage(
+              onTap: onImageTap,
+            ),
           ),
         ),
       ],
       centerTitle: true,
       title: InkWell(
-        onTap: () {},
+        onTap: onTitleTap,
         child: Container(
           height: preferredSize.height,
           width: preferredSize.width,

lib/src/channel_image.dart

@@ -47,6 +47,7 @@ class ChannelImage extends StatelessWidget {
     Key key,
     this.channel,
     this.constraints,
+    this.onTap,
   }) : super(key: key);
 
   /// The channel to show the image of
@@ -55,6 +56,9 @@ class ChannelImage extends StatelessWidget {
   /// The diameter of the image
   final BoxConstraints constraints;
 
+  /// The function called when the image is tapped
+  final VoidCallback onTap;
+
   @override
   Widget build(BuildContext context) {
     final client = StreamChat.of(context);
@@ -86,25 +90,36 @@ class ChannelImage extends StatelessWidget {
               decoration: BoxDecoration(
                 color: StreamChatTheme.of(context).accentColor,
               ),
-              child: image != null
-                  ? CachedNetworkImage(
-                      imageUrl: image,
-                      errorWidget: (_, __, ___) {
-                        return Center(
-                          child: Text(
-                            snapshot.data?.containsKey('name') ?? false
-                                ? snapshot.data['name'][0]
-                                : '',
-                            style: TextStyle(
-                              color: Colors.white,
-                              fontWeight: FontWeight.bold,
-                            ),
-                          ),
-                        );
-                      },
-                      fit: BoxFit.cover,
-                    )
-                  : SizedBox(),
+              child: Stack(
+                fit: StackFit.expand,
+                children: <Widget>[
+                  image != null
+                      ? CachedNetworkImage(
+                          imageUrl: image,
+                          errorWidget: (_, __, ___) {
+                            return Center(
+                              child: Text(
+                                snapshot.data?.containsKey('name') ?? false
+                                    ? snapshot.data['name'][0]
+                                    : '',
+                                style: TextStyle(
+                                  color: Colors.white,
+                                  fontWeight: FontWeight.bold,
+                                ),
+                              ),
+                            );
+                          },
+                          fit: BoxFit.cover,
+                        )
+                      : SizedBox(),
+                  Material(
+                    color: Colors.transparent,
+                    child: InkWell(
+                      onTap: onTap,
+                    ),
+                  ),
+                ],
+              ),
             ),
           );
         });