implemented support for viewing large group profile pictures

lib/widget/large_profile_picture_view.dart

@@ -1,20 +1,36 @@
 import 'package:flutter/material.dart';
 import 'package:photo_view/photo_view.dart';
 
+import '../model/account_data.dart';
 import '../model/endpoint_data.dart';
 
 class LargeProfilePictureView extends StatelessWidget {
-  final String username;
-  const LargeProfilePictureView(this.username, {super.key});
+  final String id;
+  final bool isGroup;
+
+  const LargeProfilePictureView({
+    required this.id,
+    this.isGroup = false,
+    super.key,
+  });
+
+  String _imageUrl() {
+    final host = EndpointData().nextcloud().full();
+    if (isGroup) {
+      return 'https://$host/ocs/v2.php/apps/spreed/api/v1/room/$id/avatar';
+    }
+    return 'https://$host/avatar/$id/1024';
+  }
 
   @override
   Widget build(BuildContext context) => Scaffold(
-    appBar: AppBar(title: const Text('Profilbild')),
+    appBar: AppBar(title: Text(isGroup ? 'Gruppenbild' : 'Profilbild')),
     body: PhotoView(
       minScale: 0.5,
       maxScale: 3.0,
       imageProvider: Image.network(
-        'https://${EndpointData().nextcloud().full()}/avatar/$username/1024',
+        _imageUrl(),
+        headers: {'Authorization': AccountData().getBasicAuthHeader()},
       ).image,
       backgroundDecoration: BoxDecoration(
         color: Theme.of(context).colorScheme.surface,