feat: Added sticky header to display position data

lib/src/message_list_view.dart

@@ -6,6 +6,7 @@ import 'package:stream_chat/stream_chat.dart';
 import 'package:stream_chat_flutter/src/message_widget.dart';
 import 'package:stream_chat_flutter/src/system_message.dart';
 import 'package:visibility_detector/visibility_detector.dart';
+import 'package:widgets_visibility_provider/widgets_visibility_provider.dart';
 
 import '../stream_chat_flutter.dart';
 import 'date_divider.dart';
@@ -149,13 +150,16 @@ class _MessageListViewState extends State<MessageListView> {
   List<Message> _newMessageList = [];
   Function _onThreadTap;
   bool _showScrollToBottom = false;
+  var positionData;
 
   @override
   Widget build(BuildContext context) {
     final streamChannel = StreamChannel.of(context);
 
     /// TODO: find a better solution when (https://github.com/flutter/flutter/issues/21023) is fixed
-    return Stack(
+    return WidgetsVisibilityProvider(
+      condition: (c) => null,
+      child: Stack(
         children: [
           NotificationListener<ScrollNotification>(
             onNotification: (_) {
@@ -268,7 +272,7 @@ class _MessageListViewState extends State<MessageListView> {
                     );
                   }
 
-                return messageWidget;
+                  return VisibleNotifierWidget(child: messageWidget);
                 },
                 childCount: _messages.length + 2,
                 findChildIndexCallback: (key) {
@@ -292,7 +296,21 @@ class _MessageListViewState extends State<MessageListView> {
                   }
                   return _buildScrollToBottom(streamChannel);
                 }),
+          Positioned(
+            top: 20.0,
+            child: WidgetsVisibilityListener(
+               listener: (context, event) {
+                 setState(() {
+                   positionData = event.positionDataList.first.startPosition;
+                 });
+               },
+               child: Chip(
+                 label: Text(positionData.toString()),
+               ),
+             ),
+          ),
         ],
+      ),
     );
   }
 

pubspec.yaml

@@ -30,6 +30,7 @@ dependencies:
   flutter_slidable: ^0.5.4
   carousel_slider: ^2.2.1
   clipboard: ^0.1.2+8
+  widgets_visibility_provider: ^2.0.2
 
 flutter:
   fonts: