Add button to change image of chat

lib/room.dart

@@ -1,5 +1,7 @@
 import 'dart:async';
+import 'dart:io';
 
+import 'package:file_picker/file_picker.dart';
 import 'package:flutter/material.dart';
 import 'package:matrix/matrix.dart';
 
@@ -34,6 +36,16 @@ class _RoomPageState extends State<RoomPage> {
     });
   }
 
+  void setAvatar() async {
+    final participants = widget.room.getParticipants();
+    final picked = await FilePicker.platform.pickFiles(type: FileType.image);
+    if (picked == null) return;
+    final file = File(picked.files.single.path!);
+    final bytes = await file.readAsBytes();
+    final uri = await widget.room.client.uploadContent(bytes);
+    await widget.room.client.setAvatarUrl(participants[0].id, uri);
+  }
+
   @override
   void dispose() {
     super.dispose();
@@ -90,6 +102,9 @@ class _RoomPageState extends State<RoomPage> {
       appBar: AppBar(
         backgroundColor: Theme.of(context).colorScheme.inversePrimary,
         title: Text(widget.room.getLocalizedDisplayname()),
+        actions: [
+          IconButton(onPressed: setAvatar, icon: const Icon(Icons.image))
+        ],
       ),
       body: Padding(
           padding: const EdgeInsets.all(16.0),