loading state and error handling refactor

lib/api/errors/app_exception.dart

@@ -0,0 +1,16 @@
+abstract class AppException implements Exception {
+  final String userMessage;
+  final String? technicalDetails;
+  final bool allowRetry;
+
+  const AppException({
+    required this.userMessage,
+    this.technicalDetails,
+    this.allowRetry = true,
+  });
+
+  @override
+  String toString() => technicalDetails == null
+      ? '$runtimeType: $userMessage'
+      : '$runtimeType: $userMessage ($technicalDetails)';
+}

lib/api/errors/auth_exception.dart

@@ -0,0 +1,23 @@
+import 'app_exception.dart';
+
+class AuthException extends AppException {
+  final int statusCode;
+
+  const AuthException({
+    required this.statusCode,
+    required super.userMessage,
+    super.technicalDetails,
+  }) : super(allowRetry: false);
+
+  factory AuthException.unauthorized({String? technicalDetails}) => AuthException(
+        statusCode: 401,
+        userMessage: 'Bitte melde dich erneut an, um fortzufahren.',
+        technicalDetails: technicalDetails,
+      );
+
+  factory AuthException.forbidden({String? technicalDetails}) => AuthException(
+        statusCode: 403,
+        userMessage: 'Du hast keine Berechtigung für diese Aktion.',
+        technicalDetails: technicalDetails,
+      );
+}

lib/api/errors/error_mapper.dart

@@ -0,0 +1,64 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:http/http.dart' as http;
+
+import '../apiError.dart';
+import '../marianumcloud/talk/talkError.dart';
+import '../webuntis/webuntisError.dart';
+import 'app_exception.dart';
+import 'network_exception.dart';
+import 'parse_exception.dart';
+import 'talk_exception.dart';
+import 'webuntis_exception.dart';
+
+const String _defaultFallback = 'Etwas ist schiefgelaufen. Bitte versuche es erneut.';
+
+String errorToUserMessage(Object? error, {String fallback = _defaultFallback}) {
+  if (error == null) return fallback;
+  if (error is AppException) return error.userMessage;
+
+  if (error is TalkError) return TalkException(error).userMessage;
+  if (error is WebuntisError) return WebuntisException(error).userMessage;
+
+  if (error is SocketException) {
+    return const NetworkException().userMessage;
+  }
+  if (error is TimeoutException) {
+    return NetworkException.timeout().userMessage;
+  }
+  if (error is http.ClientException) {
+    return const NetworkException().userMessage;
+  }
+  if (error is HandshakeException) {
+    return 'Sichere Verbindung konnte nicht hergestellt werden.';
+  }
+  if (error is FormatException) {
+    return const ParseException().userMessage;
+  }
+  if (error is ApiError) {
+    return _stripDioPrefix(error.message);
+  }
+
+  return fallback;
+}
+
+String? errorToTechnicalDetails(Object? error) {
+  if (error == null) return null;
+  if (error is AppException) return error.technicalDetails ?? error.toString();
+  if (error is TalkError) return TalkException(error).technicalDetails;
+  if (error is WebuntisError) return WebuntisException(error).technicalDetails;
+  return error.toString();
+}
+
+bool errorAllowsRetry(Object? error) {
+  if (error == null) return true;
+  if (error is AppException) return error.allowRetry;
+  return true;
+}
+
+String _stripDioPrefix(String raw) {
+  // ApiError messages embed full request URIs; only surface the first line.
+  final firstLine = raw.split('\n').first.trim();
+  return firstLine.isEmpty ? _defaultFallback : firstLine;
+}

lib/api/errors/network_exception.dart

@@ -0,0 +1,13 @@
+import 'app_exception.dart';
+
+class NetworkException extends AppException {
+  const NetworkException({
+    super.userMessage = 'Keine Internetverbindung. Bitte prüfe dein Netzwerk und versuche es erneut.',
+    super.technicalDetails,
+  }) : super(allowRetry: true);
+
+  factory NetworkException.timeout({String? technicalDetails}) => NetworkException(
+        userMessage: 'Der Server hat zu lange gebraucht. Bitte versuche es erneut.',
+        technicalDetails: technicalDetails,
+      );
+}

lib/api/errors/not_found_exception.dart

@@ -0,0 +1,8 @@
+import 'app_exception.dart';
+
+class NotFoundException extends AppException {
+  const NotFoundException({
+    super.userMessage = 'Der angeforderte Eintrag wurde nicht gefunden.',
+    super.technicalDetails,
+  }) : super(allowRetry: false);
+}

lib/api/errors/parse_exception.dart

@@ -0,0 +1,8 @@
+import 'app_exception.dart';
+
+class ParseException extends AppException {
+  const ParseException({
+    super.userMessage = 'Die Antwort des Servers konnte nicht gelesen werden.',
+    super.technicalDetails,
+  }) : super(allowRetry: true);
+}

lib/api/errors/server_exception.dart

@@ -0,0 +1,14 @@
+import 'app_exception.dart';
+
+class ServerException extends AppException {
+  final int statusCode;
+
+  ServerException({
+    required this.statusCode,
+    String? userMessage,
+    super.technicalDetails,
+  }) : super(
+          userMessage: userMessage ?? 'Der Server hat gerade Probleme (Status $statusCode). Bitte später erneut versuchen.',
+          allowRetry: true,
+        );
+}

lib/api/errors/talk_exception.dart

@@ -0,0 +1,33 @@
+import '../marianumcloud/talk/talkError.dart';
+import 'app_exception.dart';
+
+class TalkException extends AppException {
+  final TalkError source;
+
+  TalkException(this.source)
+      : super(
+          userMessage: _mapMessage(source),
+          technicalDetails: 'Talk ${source.status} (${source.code}): ${source.message}',
+          allowRetry: source.code >= 500,
+        );
+
+  static String _mapMessage(TalkError e) {
+    switch (e.code) {
+      case 401:
+        return 'Bitte melde dich erneut an, um auf Talk zuzugreifen.';
+      case 403:
+        return 'Du hast keine Berechtigung für diese Talk-Aktion.';
+      case 404:
+        return 'Dieser Chat existiert nicht oder wurde entfernt.';
+      case 412:
+        return 'Diese Aktion ist im aktuellen Chat-Zustand nicht erlaubt.';
+      case 429:
+        return 'Zu viele Anfragen. Bitte kurz warten und erneut versuchen.';
+      default:
+        if (e.code >= 500) {
+          return 'Talk-Server hat gerade Probleme (${e.code}).';
+        }
+        return e.message.isNotEmpty ? e.message : 'Talk meldet einen Fehler (${e.code}).';
+    }
+  }
+}

lib/api/errors/webuntis_exception.dart

@@ -0,0 +1,31 @@
+import '../webuntis/webuntisError.dart';
+import 'app_exception.dart';
+
+class WebuntisException extends AppException {
+  final WebuntisError source;
+
+  WebuntisException(this.source)
+      : super(
+          userMessage: _mapMessage(source),
+          technicalDetails: 'WebUntis (${source.code}): ${source.message}',
+          allowRetry: true,
+        );
+
+  static String _mapMessage(WebuntisError e) {
+    switch (e.code) {
+      case -8504:
+      case -8502:
+        return 'WebUntis-Anmeldung abgelaufen. Bitte erneut anmelden.';
+      case -8520:
+        return 'Bitte melde dich erneut an.';
+      case -7004:
+        return 'Für diesen Zeitraum sind keine Stundenplandaten verfügbar.';
+      case -32601:
+        return 'WebUntis kennt diese Anfrage nicht. Bitte App aktualisieren.';
+      default:
+        return e.message.isNotEmpty
+            ? 'WebUntis: ${e.message}'
+            : 'WebUntis konnte die Anfrage nicht bearbeiten (Code ${e.code}).';
+    }
+  }
+}

lib/api/marianumcloud/talk/talkApi.dart

@@ -1,11 +1,17 @@
+import 'dart:async';
 import 'dart:developer';
+import 'dart:io';
 
 import 'package:http/http.dart' as http;
 
-import '../../apiError.dart';
 import '../../apiParams.dart';
 import '../../apiRequest.dart';
 import '../../apiResponse.dart';
+import '../../errors/auth_exception.dart';
+import '../../errors/network_exception.dart';
+import '../../errors/not_found_exception.dart';
+import '../../errors/parse_exception.dart';
+import '../../errors/server_exception.dart';
 import '../nextcloud_ocs.dart';
 
 enum TalkApiMethod {
@@ -32,16 +38,32 @@ abstract class TalkApi<T extends ApiResponse?> extends ApiRequest {
     final endpoint = NextcloudOcs.uri('apps/spreed/api/$path', queryParameters: getParameters);
     final mergedHeaders = {...NextcloudOcs.headers(), ...?headers};
 
-    http.Response? data;
+    final http.Response data;
     try {
-      data = await request(endpoint, body, mergedHeaders);
-      if (data == null) throw Exception('No response Data');
-      if (data.statusCode >= 400 || data.statusCode < 200) {
-        throw Exception("Response status code '${data.statusCode}' might indicate an error");
+      final raw = await request(endpoint, body, mergedHeaders);
+      if (raw == null) {
+        throw const NetworkException(
+          userMessage: 'Keine Antwort vom Talk-Server erhalten.',
+          technicalDetails: 'Talk request returned null',
+        );
       }
-    } catch (e) {
-      log(e.toString());
-      throw ApiError('Request $endpoint could not be dispatched: ${e.toString()}');
+      data = raw;
+    } on SocketException catch (e) {
+      throw NetworkException(technicalDetails: 'Talk $endpoint: ${e.message}');
+    } on TimeoutException catch (e) {
+      throw NetworkException.timeout(technicalDetails: 'Talk $endpoint: $e');
+    } on http.ClientException catch (e) {
+      throw NetworkException(technicalDetails: 'Talk $endpoint: ${e.message}');
+    }
+
+    final status = data.statusCode;
+    if (status < 200 || status >= 300) {
+      final detail = 'Talk $endpoint -> HTTP $status';
+      log(detail);
+      if (status == 401) throw AuthException.unauthorized(technicalDetails: detail);
+      if (status == 403) throw AuthException.forbidden(technicalDetails: detail);
+      if (status == 404) throw NotFoundException(technicalDetails: detail);
+      throw ServerException(statusCode: status, technicalDetails: detail);
     }
 
     try {
@@ -49,10 +71,7 @@ abstract class TalkApi<T extends ApiResponse?> extends ApiRequest {
       assembled?.headers = data.headers;
       return assembled;
     } catch (e) {
-      final message = 'Error assembling Talk API ${T.toString()} message: ${e.toString()}'
-          ' response with request body: $body and request headers: $mergedHeaders';
-      log(message);
-      throw Exception(message);
+      throw ParseException(technicalDetails: 'Talk $endpoint assemble: $e');
     }
   }
 }

lib/api/mhsl/mhslApi.dart

@@ -1,9 +1,14 @@
+import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
 
 import 'package:http/http.dart' as http;
 import 'package:jiffy/jiffy.dart';
-import '../apiError.dart';
+
 import '../apiRequest.dart';
+import '../errors/network_exception.dart';
+import '../errors/parse_exception.dart';
+import '../errors/server_exception.dart';
 
 abstract class MhslApi<T> extends ApiRequest {
   String subpath;
@@ -15,18 +20,38 @@ abstract class MhslApi<T> extends ApiRequest {
   T assemble(String raw);
 
   Future<T> run() async {
-    var endpoint = Uri.parse('https://mhsl.eu/marianum/marianummobile/$subpath');
+    final endpoint = Uri.parse('https://mhsl.eu/marianum/marianummobile/$subpath');
 
-    var data = await request(endpoint);
-    if(data == null) {
-      throw ApiError('Request could not be dispatched!');
+    final http.Response data;
+    try {
+      final raw = await request(endpoint);
+      if (raw == null) {
+        throw const NetworkException(
+          userMessage: 'Keine Antwort vom MHSL-Dienst erhalten.',
+          technicalDetails: 'mhsl request returned null',
+        );
+      }
+      data = raw;
+    } on SocketException catch (e) {
+      throw NetworkException(technicalDetails: 'mhsl $subpath: ${e.message}');
+    } on TimeoutException catch (e) {
+      throw NetworkException.timeout(technicalDetails: 'mhsl $subpath: $e');
+    } on http.ClientException catch (e) {
+      throw NetworkException(technicalDetails: 'mhsl $subpath: ${e.message}');
     }
 
-    if(data.statusCode > 299) {
-      throw ApiError('Non 200 Status code from mhsl services: $subpath: ${data.statusCode}');
+    if (data.statusCode > 299) {
+      throw ServerException(
+        statusCode: data.statusCode,
+        technicalDetails: 'mhsl $subpath HTTP ${data.statusCode}',
+      );
     }
 
-    return assemble(utf8.decode(data.bodyBytes));
+    try {
+      return assemble(utf8.decode(data.bodyBytes));
+    } catch (e) {
+      throw ParseException(technicalDetails: 'mhsl $subpath assemble: $e');
+    }
   }
 
   static String dateTimeToJson(DateTime time) => Jiffy.parseFromDateTime(time).format(pattern: 'yyyy-MM-dd HH:mm:ss');

lib/api/webuntis/webuntisApi.dart

@@ -1,10 +1,15 @@
+import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
+
 import 'package:http/http.dart' as http;
 
 import '../../model/endpoint_data.dart';
 import '../apiParams.dart';
 import '../apiRequest.dart';
 import '../apiResponse.dart';
+import '../errors/network_exception.dart';
+import '../errors/parse_exception.dart';
 import 'queries/authenticate/authenticate.dart';
 import 'webuntisError.dart';
 
@@ -29,10 +34,15 @@ abstract class WebuntisApi extends ApiRequest {
     var data = await post(query, {'Cookie': 'JSESSIONID=$sessionId'});
     response = data;
 
-    dynamic jsonData = jsonDecode(data.body);
+    final dynamic jsonData;
+    try {
+      jsonData = jsonDecode(data.body);
+    } on FormatException catch (e) {
+      throw ParseException(technicalDetails: 'WebUntis JSON decode: ${e.message}');
+    }
     if(jsonData['error'] != null) {
       if(jsonData['error']['code'] == -8520) {
-        if(retry) throw WebuntisError('Authentication was tried (probably session timeout), but was not successful!', 1);
+        if(retry) throw WebuntisError('Authentication was tried (probably session timeout), but was not successful!', -8520);
         await Authenticate.createSession();
         return await this.query(untis, retry: true);
       } else {
@@ -51,10 +61,16 @@ abstract class WebuntisApi extends ApiRequest {
 
   String _body() => genericParam == null ? '{}' : jsonEncode(genericParam);
 
-  Future<http.Response> post(String data, Map<String, String>? headers) async => await http
-        .post(endpoint, body: data, headers: headers)
-        .timeout(
-        const Duration(seconds: 10),
-        onTimeout: () => throw WebuntisError('Timeout', 1)
-    );
+  Future<http.Response> post(String data, Map<String, String>? headers) async {
+    try {
+      return await http.post(endpoint, body: data, headers: headers).timeout(
+            const Duration(seconds: 10),
+            onTimeout: () => throw NetworkException.timeout(technicalDetails: 'WebUntis $method timed out after 10s'),
+          );
+    } on SocketException catch (e) {
+      throw NetworkException(technicalDetails: 'WebUntis $method: ${e.message}');
+    } on http.ClientException catch (e) {
+      throw NetworkException(technicalDetails: 'WebUntis $method: ${e.message}');
+    }
+  }
 }

lib/main.dart

@@ -32,7 +32,7 @@ import 'storage/settings.dart';
 import 'theming/dark_app_theme.dart';
 import 'theming/light_app_theme.dart';
 import 'view/login/login.dart';
-import 'widget/placeholder_view.dart';
+import 'widget/app_progress_indicator.dart';
 
 Future<void> main() async {
   log('MarianumMobile started');
@@ -68,9 +68,21 @@ Future<void> main() async {
   );
 
   if (kReleaseMode) {
-    ErrorWidget.builder = (error) => PlaceholderView(
-          icon: Icons.phonelink_erase_rounded,
-          text: error.toStringShort(),
+    ErrorWidget.builder = (error) => Material(
+          color: Colors.white,
+          child: Center(
+            child: Padding(
+              padding: const EdgeInsets.all(24),
+              child: Column(
+                mainAxisSize: MainAxisSize.min,
+                children: [
+                  const Icon(Icons.phonelink_erase_rounded, size: 40),
+                  const SizedBox(height: 12),
+                  Text(error.toStringShort(), textAlign: TextAlign.center),
+                ],
+              ),
+            ),
+          ),
         );
   }
 
@@ -156,7 +168,18 @@ class _MainState extends State<Main> {
                         case AccountStatus.loggedOut:
                           return const Login();
                         case AccountStatus.undefined:
-                          return const PlaceholderView(icon: Icons.timer, text: 'Daten werden geladen');
+                          return const Scaffold(
+                            body: Center(
+                              child: Column(
+                                mainAxisAlignment: MainAxisAlignment.center,
+                                children: [
+                                  AppProgressIndicator.large(),
+                                  SizedBox(height: 16),
+                                  Text('Konto wird geladen…'),
+                                ],
+                              ),
+                            ),
+                          );
                       }
                     },
                   ),

lib/state/app/infrastructure/loadableState/bloc/loadable_state_bloc.dart

@@ -41,6 +41,12 @@ class LoadableStateBloc extends Bloc<LoadableStateEvent, LoadableStateState> {
       ? Colors.grey.shade600
       : Theme.of(context).primaryColor;
 
+  Color connectionForegroundColor(BuildContext context) => connectivityStatusKnown() && !isConnected()
+      ? Colors.white
+      : ThemeData.estimateBrightnessForColor(Theme.of(context).primaryColor) == Brightness.dark
+          ? Colors.white
+          : Colors.black;
+
   String connectionText({int? lastUpdated}) => connectivityStatusKnown()
       ? isConnected()
         ? 'Verbindung fehlgeschlagen'

lib/state/app/infrastructure/loadableState/loading_error.dart

@@ -6,6 +6,7 @@ part 'loading_error.freezed.dart';
 abstract class LoadingError with _$LoadingError {
   const factory LoadingError({
     required String message,
+    String? technicalDetails,
     @Default(false) bool allowRetry,
   }) = _LoadingError;
 }

lib/state/app/infrastructure/loadableState/loading_error.freezed.dart

@@ -14,7 +14,7 @@ T _$identity<T>(T value) => value;
 /// @nodoc
 mixin _$LoadingError {
 
- String get message; bool get allowRetry;
+ String get message; String? get technicalDetails; bool get allowRetry;
 /// Create a copy of LoadingError
 /// with the given fields replaced by the non-null parameter values.
 @JsonKey(includeFromJson: false, includeToJson: false)
@@ -25,16 +25,16 @@ $LoadingErrorCopyWith<LoadingError> get copyWith => _$LoadingErrorCopyWithImpl<L
 
 @override
 bool operator ==(Object other) {
-  return identical(this, other) || (other.runtimeType == runtimeType&&other is LoadingError&&(identical(other.message, message) || other.message == message)&&(identical(other.allowRetry, allowRetry) || other.allowRetry == allowRetry));
+  return identical(this, other) || (other.runtimeType == runtimeType&&other is LoadingError&&(identical(other.message, message) || other.message == message)&&(identical(other.technicalDetails, technicalDetails) || other.technicalDetails == technicalDetails)&&(identical(other.allowRetry, allowRetry) || other.allowRetry == allowRetry));
 }
 
 
 @override
-int get hashCode => Object.hash(runtimeType,message,allowRetry);
+int get hashCode => Object.hash(runtimeType,message,technicalDetails,allowRetry);
 
 @override
 String toString() {
-  return 'LoadingError(message: $message, allowRetry: $allowRetry)';
+  return 'LoadingError(message: $message, technicalDetails: $technicalDetails, allowRetry: $allowRetry)';
 }
 
 
@@ -45,7 +45,7 @@ abstract mixin class $LoadingErrorCopyWith<$Res>  {
   factory $LoadingErrorCopyWith(LoadingError value, $Res Function(LoadingError) _then) = _$LoadingErrorCopyWithImpl;
 @useResult
 $Res call({
- String message, bool allowRetry
+ String message, String? technicalDetails, bool allowRetry
 });
 
 
@@ -62,10 +62,11 @@ class _$LoadingErrorCopyWithImpl<$Res>
 
 /// Create a copy of LoadingError
 /// with the given fields replaced by the non-null parameter values.
-@pragma('vm:prefer-inline') @override $Res call({Object? message = null,Object? allowRetry = null,}) {
+@pragma('vm:prefer-inline') @override $Res call({Object? message = null,Object? technicalDetails = freezed,Object? allowRetry = null,}) {
   return _then(_self.copyWith(
 message: null == message ? _self.message : message // ignore: cast_nullable_to_non_nullable
-as String,allowRetry: null == allowRetry ? _self.allowRetry : allowRetry // ignore: cast_nullable_to_non_nullable
+as String,technicalDetails: freezed == technicalDetails ? _self.technicalDetails : technicalDetails // ignore: cast_nullable_to_non_nullable
+as String?,allowRetry: null == allowRetry ? _self.allowRetry : allowRetry // ignore: cast_nullable_to_non_nullable
 as bool,
   ));
 }
@@ -151,10 +152,10 @@ return $default(_that);case _:
 /// }
 /// ```
 
-@optionalTypeArgs TResult maybeWhen<TResult extends Object?>(TResult Function( String message,  bool allowRetry)?  $default,{required TResult orElse(),}) {final _that = this;
+@optionalTypeArgs TResult maybeWhen<TResult extends Object?>(TResult Function( String message,  String? technicalDetails,  bool allowRetry)?  $default,{required TResult orElse(),}) {final _that = this;
 switch (_that) {
 case _LoadingError() when $default != null:
-return $default(_that.message,_that.allowRetry);case _:
+return $default(_that.message,_that.technicalDetails,_that.allowRetry);case _:
   return orElse();
 
 }
@@ -172,10 +173,10 @@ return $default(_that.message,_that.allowRetry);case _:
 /// }
 /// ```
 
-@optionalTypeArgs TResult when<TResult extends Object?>(TResult Function( String message,  bool allowRetry)  $default,) {final _that = this;
+@optionalTypeArgs TResult when<TResult extends Object?>(TResult Function( String message,  String? technicalDetails,  bool allowRetry)  $default,) {final _that = this;
 switch (_that) {
 case _LoadingError():
-return $default(_that.message,_that.allowRetry);case _:
+return $default(_that.message,_that.technicalDetails,_that.allowRetry);case _:
   throw StateError('Unexpected subclass');
 
 }
@@ -192,10 +193,10 @@ return $default(_that.message,_that.allowRetry);case _:
 /// }
 /// ```
 
-@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? Function( String message,  bool allowRetry)?  $default,) {final _that = this;
+@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? Function( String message,  String? technicalDetails,  bool allowRetry)?  $default,) {final _that = this;
 switch (_that) {
 case _LoadingError() when $default != null:
-return $default(_that.message,_that.allowRetry);case _:
+return $default(_that.message,_that.technicalDetails,_that.allowRetry);case _:
   return null;
 
 }
@@ -207,10 +208,11 @@ return $default(_that.message,_that.allowRetry);case _:
 
 
 class _LoadingError implements LoadingError {
-  const _LoadingError({required this.message, this.allowRetry = false});
+  const _LoadingError({required this.message, this.technicalDetails, this.allowRetry = false});
   
 
 @override final  String message;
+@override final  String? technicalDetails;
 @override@JsonKey() final  bool allowRetry;
 
 /// Create a copy of LoadingError
@@ -223,16 +225,16 @@ _$LoadingErrorCopyWith<_LoadingError> get copyWith => __$LoadingErrorCopyWithImp
 
 @override
 bool operator ==(Object other) {
-  return identical(this, other) || (other.runtimeType == runtimeType&&other is _LoadingError&&(identical(other.message, message) || other.message == message)&&(identical(other.allowRetry, allowRetry) || other.allowRetry == allowRetry));
+  return identical(this, other) || (other.runtimeType == runtimeType&&other is _LoadingError&&(identical(other.message, message) || other.message == message)&&(identical(other.technicalDetails, technicalDetails) || other.technicalDetails == technicalDetails)&&(identical(other.allowRetry, allowRetry) || other.allowRetry == allowRetry));
 }
 
 
 @override
-int get hashCode => Object.hash(runtimeType,message,allowRetry);
+int get hashCode => Object.hash(runtimeType,message,technicalDetails,allowRetry);
 
 @override
 String toString() {
-  return 'LoadingError(message: $message, allowRetry: $allowRetry)';
+  return 'LoadingError(message: $message, technicalDetails: $technicalDetails, allowRetry: $allowRetry)';
 }
 
 
@@ -243,7 +245,7 @@ abstract mixin class _$LoadingErrorCopyWith<$Res> implements $LoadingErrorCopyWi
   factory _$LoadingErrorCopyWith(_LoadingError value, $Res Function(_LoadingError) _then) = __$LoadingErrorCopyWithImpl;
 @override @useResult
 $Res call({
- String message, bool allowRetry
+ String message, String? technicalDetails, bool allowRetry
 });
 
 
@@ -260,10 +262,11 @@ class __$LoadingErrorCopyWithImpl<$Res>
 
 /// Create a copy of LoadingError
 /// with the given fields replaced by the non-null parameter values.
-@override @pragma('vm:prefer-inline') $Res call({Object? message = null,Object? allowRetry = null,}) {
+@override @pragma('vm:prefer-inline') $Res call({Object? message = null,Object? technicalDetails = freezed,Object? allowRetry = null,}) {
   return _then(_LoadingError(
 message: null == message ? _self.message : message // ignore: cast_nullable_to_non_nullable
-as String,allowRetry: null == allowRetry ? _self.allowRetry : allowRetry // ignore: cast_nullable_to_non_nullable
+as String,technicalDetails: freezed == technicalDetails ? _self.technicalDetails : technicalDetails // ignore: cast_nullable_to_non_nullable
+as String?,allowRetry: null == allowRetry ? _self.allowRetry : allowRetry // ignore: cast_nullable_to_non_nullable
 as bool,
   ));
 }

lib/state/app/infrastructure/loadableState/view/loadable_state_consumer.dart

@@ -88,6 +88,7 @@ class LoadableStateConsumer<TController extends Bloc<LoadableHydratedBlocEvent<T
               visible: showErrorBar,
               hasContent: hasContent,
               message: loadableState.error?.message,
+              technicalDetails: loadableState.error?.technicalDetails,
               lastUpdated: loadableState.lastFetch,
             ),
             Expanded(
@@ -95,7 +96,11 @@ class LoadableStateConsumer<TController extends Bloc<LoadableHydratedBlocEvent<T
                 children: [
                   LoadableStatePrimaryLoading(visible: showPrimaryLoading),
                   LoadableStateBackgroundLoading(visible: showBackgroundLoading),
-                  LoadableStateErrorScreen(visible: showError, message: loadableState.error?.message),
+                  LoadableStateErrorScreen(
+                    visible: showError,
+                    message: loadableState.error?.message,
+                    technicalDetails: loadableState.error?.technicalDetails,
+                  ),
 
                   AnimatedOpacity(
                     opacity: hasContent ? 1.0 : 0.0,

lib/state/app/infrastructure/loadableState/view/loadable_state_error_bar.dart

@@ -10,11 +10,13 @@ class LoadableStateErrorBar extends StatelessWidget {
   final bool visible;
   final bool hasContent;
   final String? message;
+  final String? technicalDetails;
   final int? lastUpdated;
   const LoadableStateErrorBar({
     required this.visible,
     this.hasContent = false,
     this.message,
+    this.technicalDetails,
     this.lastUpdated,
     super.key,
   });
@@ -48,7 +50,12 @@ class LoadableStateErrorBar extends StatelessWidget {
                   return InkWell(
                     onTap: () {
                       if(!bloc.isConnected()) return;
-                      InfoDialog.show(context, 'Exception: ${message.toString()}');
+                      final body = [
+                        if (message != null && message!.isNotEmpty) message!,
+                        if (technicalDetails != null && technicalDetails!.isNotEmpty) technicalDetails!,
+                      ].join('\n\n');
+                      if (body.isEmpty) return;
+                      InfoDialog.show(context, body);
                     },
                     child: Container(
                       height: 20,
@@ -85,13 +92,17 @@ class _LoadableStateErrorBarTextState extends State<LoadableStateErrorBarText> {
   @override
   Widget build(BuildContext context) {
     var bloc = context.watch<LoadableStateBloc>();
+    final foreground = bloc.connectionForegroundColor(context);
 
     return Row(
       mainAxisAlignment: MainAxisAlignment.center,
       children: [
-        Icon(bloc.connectionIcon(), size: 14),
+        Icon(bloc.connectionIcon(), size: 14, color: foreground),
         const SizedBox(width: 10),
-        Text(bloc.connectionText(lastUpdated: widget.lastUpdated), style: const TextStyle(fontSize: 12))
+        Text(
+          bloc.connectionText(lastUpdated: widget.lastUpdated),
+          style: TextStyle(fontSize: 12, color: foreground),
+        ),
       ],
     );
   }

lib/state/app/infrastructure/loadableState/view/loadable_state_error_screen.dart

@@ -1,49 +1,69 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
+import '../../../../../widget/info_dialog.dart';
 import '../bloc/loadable_state_bloc.dart';
 import 'loadable_state_consumer.dart';
 
 class LoadableStateErrorScreen extends StatelessWidget {
   final bool visible;
   final String? message;
-  const LoadableStateErrorScreen({required this.visible, this.message, super.key});
-
+  final String? technicalDetails;
+  const LoadableStateErrorScreen({
+    required this.visible,
+    this.message,
+    this.technicalDetails,
+    super.key,
+  });
 
   @override
   Widget build(BuildContext context) {
     final bloc = context.watch<LoadableStateBloc>();
+    final isOffline = bloc.connectivityStatusKnown() && !bloc.isConnected();
+    final headline = isOffline ? bloc.connectionText() : (message ?? bloc.connectionText());
+
     return AnimatedOpacity(
       opacity: visible ? 1.0 : 0.0,
       duration: LoadableStateConsumer.animationDuration,
       curve: Curves.easeInOut,
       child: !visible ? null : Center(
-        child: Column(
-          mainAxisAlignment: MainAxisAlignment.center,
-          crossAxisAlignment: CrossAxisAlignment.center,
-          children: [
-            Icon(bloc.connectionIcon(), size: 40),
-            const SizedBox(height: 10),
-            Text(bloc.connectionText(), style: const TextStyle(fontSize: 20)),
-
-            if(bloc.allowRetry()) ...[
-              const SizedBox(height: 10),
-              TextButton(onPressed: () => bloc.reFetch!(), child: const Text('Erneut versuschen')),
-              const SizedBox(height: 40),
-              Padding(
-                padding: const EdgeInsets.symmetric(horizontal: 20),
-                child: Text(
-                  message ?? 'Task failed successfully :)',
-                  style: TextStyle(
-                      color: Theme.of(context).hintColor,
-                      fontSize: 12
-                  ),
-                  maxLines: 10,
-                  overflow: TextOverflow.ellipsis,
-                ),
+        child: Padding(
+          padding: const EdgeInsets.symmetric(horizontal: 24),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            crossAxisAlignment: CrossAxisAlignment.center,
+            children: [
+              Icon(bloc.connectionIcon(), size: 40),
+              const SizedBox(height: 12),
+              Text(
+                headline,
+                style: const TextStyle(fontSize: 20),
+                textAlign: TextAlign.center,
               ),
+              if (!isOffline && message != null && message != headline) ...[
+                const SizedBox(height: 8),
+                Text(
+                  message!,
+                  style: TextStyle(color: Theme.of(context).hintColor, fontSize: 14),
+                  textAlign: TextAlign.center,
+                ),
+              ],
+              if (bloc.allowRetry()) ...[
+                const SizedBox(height: 16),
+                TextButton(
+                  onPressed: () => bloc.reFetch!(),
+                  child: const Text('Erneut versuchen'),
+                ),
+              ],
+              if (technicalDetails != null) ...[
+                const SizedBox(height: 4),
+                TextButton(
+                  onPressed: () => InfoDialog.show(context, technicalDetails!),
+                  child: const Text('Details anzeigen'),
+                ),
+              ],
             ],
-          ],
+          ),
         ),
       ),
     );

lib/state/app/infrastructure/loadableState/view/loadable_state_primary_loading.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+import '../../../../../widget/app_progress_indicator.dart';
 import 'loadable_state_consumer.dart';
 
 class LoadableStatePrimaryLoading extends StatelessWidget {
@@ -11,6 +12,6 @@ class LoadableStatePrimaryLoading extends StatelessWidget {
       opacity: visible ? 1.0 : 0.0,
       duration: LoadableStateConsumer.animationDuration,
       curve: Curves.easeInOut,
-      child: const Center(child: CircularProgressIndicator()),
+      child: const Center(child: AppProgressIndicator.large()),
     );
 }

lib/state/app/infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart

@@ -2,6 +2,7 @@ import 'dart:developer';
 
 import 'package:hydrated_bloc/hydrated_bloc.dart';
 
+import '../../../../../api/errors/error_mapper.dart';
 import '../../loadableState/loading_error.dart';
 import '../../repository/repository.dart';
 import 'loadable_hydrated_bloc_event.dart';
@@ -78,8 +79,9 @@ abstract class LoadableHydratedBloc<
       (e) {
         log('Error while fetching ${TState.toString()}: ${e.toString()}');
         add(Error(LoadingError(
-          message: e.message ?? e.toString(),
-          allowRetry: true,
+          message: errorToUserMessage(e),
+          technicalDetails: errorToTechnicalDetails(e),
+          allowRetry: errorAllowsRetry(e),
         )));
       },
     ).then((value) {

lib/state/app/modules/chat/bloc/chat_bloc.dart

@@ -1,3 +1,4 @@
+import '../../../../../api/errors/error_mapper.dart';
 import '../../../../../api/marianumcloud/talk/chat/getChatResponse.dart';
 import '../../../infrastructure/loadableState/loading_error.dart';
 import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart';
@@ -75,8 +76,9 @@ class ChatBloc extends LoadableHydratedBloc<ChatEvent, ChatState, ChatRepository
     }
     if (capturedError != null) {
       add(Error(LoadingError(
-        message: capturedError.toString(),
-        allowRetry: true,
+        message: errorToUserMessage(capturedError),
+        technicalDetails: errorToTechnicalDetails(capturedError),
+        allowRetry: errorAllowsRetry(capturedError),
       )));
     }
   }

lib/state/app/modules/chatList/bloc/chat_list_bloc.dart

@@ -1,5 +1,6 @@
 import 'package:flutter_app_badge/flutter_app_badge.dart';
 
+import '../../../../../api/errors/error_mapper.dart';
 import '../../../infrastructure/loadableState/loading_error.dart';
 import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart';
 import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc_event.dart';
@@ -59,8 +60,9 @@ class ChatListBloc extends LoadableHydratedBloc<ChatListEvent, ChatListState, Ch
     }
     if (capturedError != null) {
       add(Error(LoadingError(
-        message: capturedError.toString(),
-        allowRetry: true,
+        message: errorToUserMessage(capturedError),
+        technicalDetails: errorToTechnicalDetails(capturedError),
+        allowRetry: errorAllowsRetry(capturedError),
       )));
     }
   }

lib/state/app/modules/files/bloc/files_bloc.dart

@@ -1,3 +1,4 @@
+import '../../../../../api/errors/error_mapper.dart';
 import '../../../../../api/marianumcloud/webdav/queries/listFiles/listFilesResponse.dart';
 import '../../../infrastructure/loadableState/loading_error.dart';
 import '../../../infrastructure/utilityWidgets/loadableHydratedBloc/loadable_hydrated_bloc.dart';
@@ -74,8 +75,9 @@ class FilesBloc extends LoadableHydratedBloc<FilesEvent, FilesState, FilesReposi
     }
     if (capturedError != null) {
       add(Error(LoadingError(
-        message: capturedError.toString(),
-        allowRetry: true,
+        message: errorToUserMessage(capturedError),
+        technicalDetails: errorToTechnicalDetails(capturedError),
+        allowRetry: errorAllowsRetry(capturedError),
       )));
     }
   }

lib/state/app/modules/settings/bloc/settings_cubit.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:developer';
 
 import 'package:easy_debounce/easy_debounce.dart';
@@ -9,14 +10,23 @@ import '../../app_modules.dart';
 
 class SettingsCubit extends HydratedCubit<Settings> {
   static const _debounceTag = 'settings_persist';
+  bool _emitScheduled = false;
 
   SettingsCubit() : super(DefaultSettings.get());
 
   Settings val({bool write = false}) {
     if (write) {
-      // Notify listeners immediately so the UI reflects the mutation right away;
-      // debounce the actual persistence to disk to avoid hammering on rapid edits.
-      _emitFreshInstance();
+      // Defer the emit until the synchronous mutation on the returned object
+      // has finished. Without this scheduleMicrotask the cubit emits a copy
+      // captured *before* the assignment runs, so listeners (and HydratedBloc
+      // persistence) see the old value on the first emit.
+      if (!_emitScheduled) {
+        _emitScheduled = true;
+        scheduleMicrotask(() {
+          _emitScheduled = false;
+          _emitFreshInstance();
+        });
+      }
       EasyDebounce.debounce(_debounceTag, const Duration(milliseconds: 500), _emitFreshInstance);
     }
     return state;

lib/theming/app_theme.dart

@@ -2,6 +2,17 @@ import 'package:flutter/material.dart';
 
 import '../widget/dropdown_display.dart';
 
+class AppSpacing {
+  static const double xs = 4;
+  static const double sm = 8;
+  static const double md = 16;
+  static const double lg = 24;
+  static const double xl = 40;
+}
+
+TextStyle inputErrorStyle(BuildContext context) =>
+    TextStyle(color: Theme.of(context).colorScheme.error);
+
 class AppTheme {
   static DropdownDisplay getDisplayOptions(ThemeMode theme) {
     switch(theme) {

lib/view/pages/files/files.dart

@@ -2,7 +2,6 @@ import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
-import 'package:loader_overlay/loader_overlay.dart';
 import 'package:persistent_bottom_nav_bar_v2/persistent_bottom_nav_bar_v2.dart';
 
 import '../../../api/marianumcloud/webdav/queries/listFiles/cacheableFile.dart';
@@ -12,6 +11,7 @@ import '../../../state/app/infrastructure/utilityWidgets/bloc_module.dart';
 import '../../../state/app/modules/files/bloc/files_bloc.dart';
 import '../../../state/app/modules/files/bloc/files_state.dart';
 import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
+import '../../../widget/async_action_button.dart';
 import '../../../widget/file_pick.dart';
 import '../../../widget/placeholder_view.dart';
 import 'widgets/file_element.dart';
@@ -175,12 +175,10 @@ class _FilesViewState extends State<_FilesView> {
             foldersToTop: context.watch<SettingsCubit>().val().fileSettings.sortFoldersToTop,
             reversed: currentSortDirection,
           );
-          return LoaderOverlay(
-            child: ListView.builder(
-              padding: EdgeInsets.zero,
-              itemCount: files.length,
-              itemBuilder: (context, index) => FileElement(files[index], widget.path, bloc.refresh),
-            ),
+          return ListView.builder(
+            padding: EdgeInsets.zero,
+            itemCount: files.length,
+            itemBuilder: (context, index) => FileElement(files[index], widget.path, bloc.refresh),
           );
         },
       ),
@@ -233,15 +231,17 @@ class _FilesViewState extends State<_FilesView> {
         content: TextField(
           controller: inputController,
           decoration: const InputDecoration(labelText: 'Name'),
+          autofocus: true,
         ),
         actions: [
-          TextButton(onPressed: () => Navigator.of(dialogCtx).pop(), child: const Text('Abbrechen')),
-          TextButton(
-            onPressed: () {
-              bloc.createFolder(inputController.text);
-              Navigator.of(dialogCtx).pop();
+          AsyncDialogAction(
+            confirmLabel: 'Ordner erstellen',
+            onConfirm: () async {
+              if (inputController.text.trim().isEmpty) {
+                throw Exception('Bitte einen Namen eingeben.');
+              }
+              await bloc.createFolder(inputController.text.trim());
             },
-            child: const Text('Ordner erstellen'),
           ),
         ],
       ),

lib/view/pages/files/files_upload_dialog.dart

@@ -254,7 +254,7 @@ class _FilesUploadDialogState extends State<FilesUploadDialog> {
                         border: const UnderlineInputBorder(),
                         label: Text('Datei ${index+1}'),
                         errorText: currentFile.isConflicting ? 'existiert bereits' : null,
-                        errorStyle: const TextStyle(color: Colors.red),
+                        errorStyle: TextStyle(color: Theme.of(context).colorScheme.error),
                       ),
                       onChanged: (input) {
                         currentFile.fileName = input;

lib/view/pages/files/widgets/file_element.dart

@@ -159,11 +159,12 @@ class _FileElementState extends State<FileElement> {
                   showDialog(context: context, builder: (context) => ConfirmDialog(
                     title: 'Element löschen?',
                     content: 'Das Element wird unwiederruflich gelöscht.',
-                    onConfirm: () {
-                      WebdavApi.webdav
-                          .then((value) => value.delete(PathUri.parse(widget.file.path)))
-                          .then((value) => widget.refetch());
-                    }
+                    confirmButton: 'Löschen',
+                    onConfirmAsync: () async {
+                      final webdav = await WebdavApi.webdav;
+                      await webdav.delete(PathUri.parse(widget.file.path));
+                      widget.refetch();
+                    },
                   ));
                 },
               ),

lib/view/pages/settings/sections/about_section.dart

@@ -16,7 +16,7 @@ class AboutSection extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final settings = context.read<SettingsCubit>();
+    final settings = context.watch<SettingsCubit>();
     return Column(
       children: [
         ListTile(

lib/view/pages/settings/sections/account_section.dart

@@ -22,11 +22,11 @@ class AccountSection extends StatelessWidget {
   void _showLogoutDialog(BuildContext context) {
     showDialog(
       context: context,
-      builder: (context) => ConfirmDialog(
+      builder: (dialogContext) => ConfirmDialog(
         title: 'Abmelden?',
         content: 'Möchtest du dich wirklich abmelden?',
         confirmButton: 'Abmelden',
-        onConfirm: () async {
+        onConfirmAsync: () async {
           final prefs = await SharedPreferences.getInstance();
           await prefs.clear();
           PaintingBinding.instance.imageCache.clear();

lib/view/pages/settings/sections/appearance_section.dart

@@ -9,7 +9,7 @@ class AppearanceSection extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final settings = context.read<SettingsCubit>();
+    final settings = context.watch<SettingsCubit>();
     return ListTile(
       leading: const Icon(Icons.dark_mode_outlined),
       title: const Text('Farbgebung'),

lib/view/pages/settings/sections/dev_tools_section.dart

@@ -6,6 +6,7 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../../../../routing/app_routes.dart';
 import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
+import '../../../../storage/settings.dart' as model;
 import '../../../../widget/centered_leading.dart';
 import '../../../../widget/confirm_dialog.dart';
 import '../../../../widget/debug/cache_view.dart';
@@ -28,34 +29,43 @@ class _DevToolsSectionState extends State<DevToolsSection> {
           title: const Text('Performance overlays'),
           trailing: const Icon(Icons.arrow_right),
           onTap: () {
-            showDialog(context: context, builder: (context) => SimpleDialog(
-              children: [
-                ListTile(
-                  leading: const Icon(Icons.auto_graph_outlined),
-                  title: const Text('Performance graph'),
-                  trailing: Checkbox(
-                    value: widget.settings.val().devToolsSettings.showPerformanceOverlay,
-                    onChanged: (e) => widget.settings.val(write: true).devToolsSettings.showPerformanceOverlay = e!,
-                  ),
-                ),
-                ListTile(
-                  leading: const Icon(Icons.screen_search_desktop_outlined),
-                  title: const Text('Indicate offscreen layers'),
-                  trailing: Checkbox(
-                    value: widget.settings.val().devToolsSettings.checkerboardOffscreenLayers,
-                    onChanged: (e) => widget.settings.val(write: true).devToolsSettings.checkerboardOffscreenLayers = e!,
-                  ),
-                ),
-                ListTile(
-                  leading: const Icon(Icons.imagesearch_roller_outlined),
-                  title: const Text('Indicate raster cache images'),
-                  trailing: Checkbox(
-                    value: widget.settings.val().devToolsSettings.checkerboardRasterCacheImages,
-                    onChanged: (e) => widget.settings.val(write: true).devToolsSettings.checkerboardRasterCacheImages = e!,
-                  ),
-                ),
-              ],
-            ));
+            showDialog(
+              context: context,
+              builder: (dialogCtx) => BlocBuilder<SettingsCubit, model.Settings>(
+                bloc: widget.settings,
+                builder: (_, _) {
+                  final dev = widget.settings.val().devToolsSettings;
+                  return SimpleDialog(
+                    children: [
+                      ListTile(
+                        leading: const Icon(Icons.auto_graph_outlined),
+                        title: const Text('Performance graph'),
+                        trailing: Checkbox(
+                          value: dev.showPerformanceOverlay,
+                          onChanged: (e) => widget.settings.val(write: true).devToolsSettings.showPerformanceOverlay = e!,
+                        ),
+                      ),
+                      ListTile(
+                        leading: const Icon(Icons.screen_search_desktop_outlined),
+                        title: const Text('Indicate offscreen layers'),
+                        trailing: Checkbox(
+                          value: dev.checkerboardOffscreenLayers,
+                          onChanged: (e) => widget.settings.val(write: true).devToolsSettings.checkerboardOffscreenLayers = e!,
+                        ),
+                      ),
+                      ListTile(
+                        leading: const Icon(Icons.imagesearch_roller_outlined),
+                        title: const Text('Indicate raster cache images'),
+                        trailing: Checkbox(
+                          value: dev.checkerboardRasterCacheImages,
+                          onChanged: (e) => widget.settings.val(write: true).devToolsSettings.checkerboardRasterCacheImages = e!,
+                        ),
+                      ),
+                    ],
+                  );
+                },
+              ),
+            );
           },
         ),
         ListTile(

lib/view/pages/settings/sections/files_section.dart

@@ -8,7 +8,7 @@ class FilesSection extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final settings = context.read<SettingsCubit>();
+    final settings = context.watch<SettingsCubit>();
     return Column(
       children: [
         ListTile(

lib/view/pages/settings/sections/talk_section.dart

@@ -10,7 +10,7 @@ class TalkSection extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final settings = context.read<SettingsCubit>();
+    final settings = context.watch<SettingsCubit>();
     final talkSettings = settings.val().talkSettings;
     final notificationSettings = settings.val().notificationSettings;
     return Column(

lib/view/pages/settings/sections/timetable_section.dart

@@ -2,7 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
-import '../../../../state/app/modules/timetable/bloc/timetable_bloc.dart';
 import '../../../../view/pages/timetable/data/timetable_name_mode.dart';
 
 class TimetableSection extends StatelessWidget {
@@ -10,8 +9,7 @@ class TimetableSection extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final settings = context.read<SettingsCubit>();
-    final timetableBloc = context.read<TimetableBloc>();
+    final settings = context.watch<SettingsCubit>();
     final timetableSettings = settings.val().timetableSettings;
     return Column(
       children: [
@@ -34,10 +32,8 @@ class TimetableSection extends StatelessWidget {
                       ),
                     ))
                 .toList(),
-            onChanged: (value) {
-              settings.val(write: true).timetableSettings.timetableNameMode = value!;
-              timetableBloc.refresh();
-            },
+            onChanged: (value) =>
+                settings.val(write: true).timetableSettings.timetableNameMode = value!,
           ),
         ),
         ListTile(
@@ -45,10 +41,8 @@ class TimetableSection extends StatelessWidget {
           title: const Text('Doppelstunden zusammenhängend anzeigen'),
           trailing: Checkbox(
             value: timetableSettings.connectDoubleLessons,
-            onChanged: (e) {
-              settings.val(write: true).timetableSettings.connectDoubleLessons = e!;
-              timetableBloc.refresh();
-            },
+            onChanged: (e) =>
+                settings.val(write: true).timetableSettings.connectDoubleLessons = e!,
           ),
         ),
       ],

lib/view/pages/settings/settings.dart

@@ -1,8 +1,5 @@
 import 'package:flutter/material.dart';
-import 'package:flutter_bloc/flutter_bloc.dart';
 
-import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
-import '../../../storage/settings.dart' as model;
 import 'sections/about_section.dart';
 import 'sections/account_section.dart';
 import 'sections/appearance_section.dart';
@@ -14,24 +11,22 @@ class Settings extends StatelessWidget {
   const Settings({super.key});
 
   @override
-  Widget build(BuildContext context) => BlocBuilder<SettingsCubit, model.Settings>(
-        builder: (context, _) => Scaffold(
-          appBar: AppBar(title: const Text('Einstellungen')),
-          body: ListView(
-            children: const [
-              AccountSection(),
-              Divider(),
-              AppearanceSection(),
-              Divider(),
-              TimetableSection(),
-              Divider(),
-              TalkSection(),
-              Divider(),
-              FilesSection(),
-              Divider(),
-              AboutSection(),
-            ],
-          ),
+  Widget build(BuildContext context) => Scaffold(
+        appBar: AppBar(title: const Text('Einstellungen')),
+        body: ListView(
+          children: const [
+            AccountSection(),
+            Divider(),
+            AppearanceSection(),
+            Divider(),
+            TimetableSection(),
+            Divider(),
+            TalkSection(),
+            Divider(),
+            FilesSection(),
+            Divider(),
+            AboutSection(),
+          ],
         ),
       );
 }

lib/view/pages/talk/chat_list.dart

@@ -12,6 +12,7 @@ import '../../../state/app/modules/chatList/bloc/chat_list_state.dart';
 import '../../../notification/notify_updater.dart';
 import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
 import '../../../widget/confirm_dialog.dart';
+import '../../../widget/placeholder_view.dart';
 import 'widgets/chat_tile.dart';
 import 'widgets/split_view_placeholder.dart';
 import 'join_chat.dart';
@@ -144,9 +145,7 @@ class _ChatListViewState extends State<_ChatListView> {
                   title: 'Chat starten',
                   content: "Möchtest du einen Chat mit Nutzer '$username' starten?",
                   confirmButton: 'Chat starten',
-                  onConfirm: () {
-                    bloc.createDirectChat(username);
-                  },
+                  onConfirmAsync: () => bloc.createDirectChat(username),
                 ).asDialog(context);
               });
             },
@@ -164,6 +163,13 @@ class _ChatListViewState extends State<_ChatListView> {
                 unreadToTop: talkSettings.sortUnreadToTop,
               );
 
+              if (sorted.isEmpty) {
+                return const PlaceholderView(
+                  icon: Icons.chat_bubble_outline,
+                  text: 'Noch keine Chats — starte einen über das +-Symbol.',
+                );
+              }
+
               return ListView(
                 padding: EdgeInsets.zero,
                 children: sorted.map((room) {

lib/view/pages/talk/join_chat.dart

@@ -2,9 +2,11 @@
 import 'package:async/async.dart';
 import 'package:flutter/material.dart';
 
+import '../../../api/errors/error_mapper.dart';
 import '../../../api/marianumcloud/autocomplete/autocompleteApi.dart';
 import '../../../api/marianumcloud/autocomplete/autocompleteResponse.dart';
 import '../../../model/endpoint_data.dart';
+import '../../../widget/app_progress_indicator.dart';
 import '../../../widget/placeholder_view.dart';
 
 class JoinChat extends SearchDelegate<String> {
@@ -16,17 +18,9 @@ class JoinChat extends SearchDelegate<String> {
         future: future!.value,
         builder: (context, snapshot) {
           if(snapshot.connectionState != ConnectionState.done) {
-            return Container(
-              padding: const EdgeInsets.all(10),
-              child: const Center(
-                child: SizedBox(
-                  height: 20,
-                  width: 20,
-                  child: CircularProgressIndicator(
-                    strokeWidth: 3,
-                  ),
-                ),
-              ),
+            return const Padding(
+              padding: EdgeInsets.all(10),
+              child: Center(child: AppProgressIndicator.medium()),
             );
           }
           return const SizedBox.shrink();
@@ -76,10 +70,13 @@ class JoinChat extends SearchDelegate<String> {
             }
           );
         } else if(snapshot.hasError) {
-          return const PlaceholderView(icon: Icons.search_off, text: 'Ein fehler ist aufgetreten. Bist du mit dem Internet verbunden?');
+          return PlaceholderView(
+            icon: Icons.search_off,
+            text: errorToUserMessage(snapshot.error),
+          );
         }
 
-        return const Center(child: CircularProgressIndicator());
+        return const Center(child: AppProgressIndicator.large());
       },
     );
   }

lib/view/pages/talk/widgets/chat_bubble.dart

@@ -14,6 +14,7 @@ import '../../../../api/marianumcloud/talk/reactMessage/reactMessageParams.dart'
 import '../../../../api/marianumcloud/talk/room/getRoomResponse.dart';
 import '../../../../extensions/text.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
+import '../../../../widget/async_action_button.dart';
 import '../../../../widget/loading_spinner.dart';
 import '../../files/widgets/file_element.dart';
 import '../data/chat_bubble_styles.dart';
@@ -306,22 +307,22 @@ class _ChatBubbleState extends State<ChatBubble> with SingleTickerProviderStateM
                       padding: EdgeInsets.zero,
                       backgroundColor: hasSelfReacted ? Theme.of(context).primaryColor : null,
                       onPressed: () {
-                        if(hasSelfReacted) {
-                          // Delete existing reaction
-                          DeleteReactMessage(
-                            chatToken: widget.chatData.token,
-                            messageId: widget.bubbleData.id,
-                            params: DeleteReactMessageParams(e.key),
-                          ).run().then((value) => widget.refetch(renew: true));
-
-                        } else {
-                          // Add reaction
-                          ReactMessage(
-                            chatToken: widget.chatData.token,
-                            messageId: widget.bubbleData.id,
-                            params: ReactMessageParams(e.key)
-                          ).run().then((value) => widget.refetch(renew: true));
-                        }
+                        runWithErrorDialog(context, () async {
+                          if (hasSelfReacted) {
+                            await DeleteReactMessage(
+                              chatToken: widget.chatData.token,
+                              messageId: widget.bubbleData.id,
+                              params: DeleteReactMessageParams(e.key),
+                            ).run();
+                          } else {
+                            await ReactMessage(
+                              chatToken: widget.chatData.token,
+                              messageId: widget.bubbleData.id,
+                              params: ReactMessageParams(e.key),
+                            ).run();
+                          }
+                          widget.refetch(renew: true);
+                        });
                       },
                     ),
                   );

lib/view/pages/talk/widgets/chat_message_options_dialog.dart

@@ -11,6 +11,8 @@ import '../../../../api/marianumcloud/talk/reactMessage/reactMessageParams.dart'
 import '../../../../api/marianumcloud/talk/room/getRoomResponse.dart';
 import '../../../../routing/app_routes.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
+import '../../../../widget/app_progress_indicator.dart';
+import '../../../../widget/async_action_button.dart';
 import '../../../../widget/debug/debug_tile.dart';
 
 const _commonReactions = <String>['👍', '👎', '😆', '❤️', '👀'];
@@ -78,14 +80,12 @@ Future<void> showChatMessageOptionsDialog(
             onTap: () => Navigator.of(dialogCtx).pop(),
           ),
         if (canDelete)
-          ListTile(
+          AsyncListTile(
             leading: const Icon(Icons.delete_outline),
             title: const Text('Nachricht löschen'),
-            onTap: () async {
+            onPressed: () async {
               await DeleteMessage(chatData.token, bubbleData.id).run();
-              if (!dialogCtx.mounted) return;
-              dialogCtx.read<ChatBloc>().refresh();
-              Navigator.of(dialogCtx).pop();
+              if (dialogCtx.mounted) dialogCtx.read<ChatBloc>().refresh();
             },
           ),
         DebugTile(dialogCtx).jsonData(bubbleData.toJson()),
@@ -94,7 +94,7 @@ Future<void> showChatMessageOptionsDialog(
   );
 }
 
-class _ReactionsRow extends StatelessWidget {
+class _ReactionsRow extends StatefulWidget {
   final String chatToken;
   final int messageId;
   final void Function({bool renew}) onRefetch;
@@ -107,46 +107,83 @@ class _ReactionsRow extends StatelessWidget {
     required this.dialogContext,
   });
 
-  void _react(String emoji) {
-    Navigator.of(dialogContext).pop();
-    ReactMessage(
-      chatToken: chatToken,
-      messageId: messageId,
-      params: ReactMessageParams(emoji),
-    ).run().then((_) => onRefetch(renew: true));
+  @override
+  State<_ReactionsRow> createState() => _ReactionsRowState();
+}
+
+class _ReactionsRowState extends State<_ReactionsRow> {
+  final AsyncActionController _controller = AsyncActionController();
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  Future<void> _react(String emoji) async {
+    final ok = await _controller.run(() async {
+      await ReactMessage(
+        chatToken: widget.chatToken,
+        messageId: widget.messageId,
+        params: ReactMessageParams(emoji),
+      ).run();
+    });
+    if (!mounted) return;
+    if (ok) {
+      widget.onRefetch(renew: true);
+      if (widget.dialogContext.mounted) Navigator.of(widget.dialogContext).pop();
+    }
   }
 
   @override
-  Widget build(BuildContext context) => Column(
-        mainAxisSize: MainAxisSize.min,
-        children: [
-          Wrap(
-            alignment: WrapAlignment.center,
+  Widget build(BuildContext context) => AnimatedBuilder(
+        animation: _controller,
+        builder: (context, _) {
+          final busy = _controller.busy;
+          final err = _controller.error;
+          return Column(
+            mainAxisSize: MainAxisSize.min,
             children: [
-              ..._commonReactions.map(
-                (emoji) => TextButton(
-                  style: TextButton.styleFrom(
-                    padding: EdgeInsets.zero,
-                    tapTargetSize: MaterialTapTargetSize.shrinkWrap,
-                    minimumSize: const Size(40, 40),
+              Wrap(
+                alignment: WrapAlignment.center,
+                children: [
+                  ..._commonReactions.map(
+                    (emoji) => TextButton(
+                      style: TextButton.styleFrom(
+                        padding: EdgeInsets.zero,
+                        tapTargetSize: MaterialTapTargetSize.shrinkWrap,
+                        minimumSize: const Size(40, 40),
+                      ),
+                      onPressed: busy ? null : () => _react(emoji),
+                      child: Text(emoji),
+                    ),
                   ),
-                  onPressed: () => _react(emoji),
-                  child: Text(emoji),
-                ),
+                  IconButton(
+                    onPressed: busy ? null : () => _showEmojiPicker(context),
+                    style: IconButton.styleFrom(
+                      padding: EdgeInsets.zero,
+                      tapTargetSize: MaterialTapTargetSize.shrinkWrap,
+                      minimumSize: const Size(40, 40),
+                    ),
+                    icon: busy
+                        ? const AppProgressIndicator.small()
+                        : const Icon(Icons.add_circle_outline_outlined),
+                  ),
+                ],
               ),
-              IconButton(
-                onPressed: () => _showEmojiPicker(context),
-                style: IconButton.styleFrom(
-                  padding: EdgeInsets.zero,
-                  tapTargetSize: MaterialTapTargetSize.shrinkWrap,
-                  minimumSize: const Size(40, 40),
+              if (err != null)
+                Padding(
+                  padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
+                  child: Text(
+                    err,
+                    textAlign: TextAlign.center,
+                    style: TextStyle(color: Theme.of(context).colorScheme.error, fontSize: 12),
+                  ),
                 ),
-                icon: const Icon(Icons.add_circle_outline_outlined),
-              ),
+              const Divider(),
             ],
-          ),
-          const Divider(),
-        ],
+          );
+        },
       );
 
   void _showEmojiPicker(BuildContext rowContext) {

lib/view/pages/talk/widgets/chat_textfield.dart

@@ -12,6 +12,7 @@ import '../../../../api/marianumcloud/talk/sendMessage/sendMessageParams.dart';
 import '../../../../api/marianumcloud/webdav/webdavApi.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../../../../state/app/modules/settings/bloc/settings_cubit.dart';
+import '../../../../widget/async_action_button.dart';
 import '../../../../widget/file_pick.dart';
 import '../../../../widget/focus_behaviour.dart';
 import '../../files/files_upload_dialog.dart';
@@ -30,7 +31,8 @@ class ChatTextfield extends StatefulWidget {
 class _ChatTextfieldState extends State<ChatTextfield> {
   late SettingsCubit settings;
   final TextEditingController _textBoxController = TextEditingController();
-  bool isLoading = false;
+  final AsyncActionController _sendController = AsyncActionController();
+  String? _sendError;
 
   void share(String shareFolder, List<String> filePaths) {
     for (final element in filePaths) {
@@ -92,6 +94,29 @@ class _ChatTextfieldState extends State<ChatTextfield> {
     }
   }
 
+  @override
+  void dispose() {
+    _sendController.dispose();
+    super.dispose();
+  }
+
+  Future<void> _sendMessage(ChatBloc chatBloc) async {
+    if (_textBoxController.text.isEmpty) return;
+    final text = _textBoxController.text;
+    final replyTo = chatBloc.state.data?.referenceMessageId?.toString();
+    setState(() => _sendError = null);
+    await SendMessage(
+      widget.sendToToken,
+      SendMessageParams(text, replyTo: replyTo),
+    ).run();
+    if (!mounted) return;
+    chatBloc.refresh();
+    _textBoxController.text = '';
+    _setDraft('');
+    chatBloc.setReferenceMessageId(null);
+    _setDraftReply(null);
+  }
+
   @override
   Widget build(BuildContext context) {
     _textBoxController.text = settings.val().talkSettings.drafts[widget.sendToToken] ?? '';
@@ -135,6 +160,14 @@ class _ChatTextfieldState extends State<ChatTextfield> {
           child: Column(
             children: [
               replyBanner,
+              if (_sendError != null)
+                Padding(
+                  padding: const EdgeInsets.only(bottom: 4),
+                  child: Text(
+                    _sendError!,
+                    style: TextStyle(color: Theme.of(context).colorScheme.error, fontSize: 12),
+                  ),
+                ),
               Row(children: <Widget>[
                 GestureDetector(
                   onTap: () {
@@ -200,36 +233,19 @@ class _ChatTextfieldState extends State<ChatTextfield> {
                   ),
                 ),
                 const SizedBox(width: 15),
-                FloatingActionButton(
-                  mini: true,
-                  onPressed: () {
-                    if (_textBoxController.text.isEmpty || isLoading) return;
-
-                    setState(() => isLoading = true);
-                    SendMessage(
-                      widget.sendToToken,
-                      SendMessageParams(
-                        _textBoxController.text,
-                        replyTo: chatBloc.state.data?.referenceMessageId?.toString(),
-                      ),
-                    ).run().then((_) {
-                      if (!mounted) return;
-                      chatBloc.refresh();
-                      setState(() => isLoading = false);
-                      _textBoxController.text = '';
-                      _setDraft('');
-                      chatBloc.setReferenceMessageId(null);
-                      _setDraftReply(null);
-                    });
-                  },
-                  backgroundColor: Theme.of(context).primaryColor,
-                  elevation: 5,
-                  child: isLoading
-                      ? Container(
-                          padding: const EdgeInsets.all(10),
-                          child: const CircularProgressIndicator(color: Colors.white, strokeWidth: 2),
-                        )
-                      : const Icon(Icons.send, color: Colors.white, size: 18),
+                ValueListenableBuilder<TextEditingValue>(
+                  valueListenable: _textBoxController,
+                  builder: (context, value, _) => AsyncFab(
+                    mini: true,
+                    heroTag: 'chatSend_${widget.sendToToken}',
+                    icon: Icons.send,
+                    backgroundColor: Theme.of(context).primaryColor,
+                    foregroundColor: Colors.white,
+                    controller: _sendController,
+                    onPressed: value.text.trim().isEmpty ? null : () => _sendMessage(chatBloc),
+                    onError: (message) => setState(() => _sendError = message),
+                    onSuccess: () => setState(() => _sendError = null),
+                  ),
                 ),
               ]),
             ],

lib/view/pages/talk/widgets/chat_tile.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -11,6 +12,7 @@ import '../../../../api/marianumcloud/talk/setReadMarker/setReadMarkerParams.dar
 import '../../../../model/account_data.dart';
 import '../../../../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../../../../state/app/modules/chatList/bloc/chat_list_bloc.dart';
+import '../../../../widget/async_action_button.dart';
 import '../../../../widget/confirm_dialog.dart';
 import '../../../../widget/debug/debug_tile.dart';
 import '../../../../widget/user_avatar.dart';
@@ -42,15 +44,14 @@ class _ChatTileState extends State<ChatTile> {
 
   void _refreshList() => context.read<ChatListBloc>().refresh();
 
-  void setCurrentAsRead() {
-    SetReadMarker(
+  Future<void> _setCurrentAsRead() async {
+    await SetReadMarker(
       widget.data.token,
       true,
       setReadMarkerParams: SetReadMarkerParams(lastReadMessage: widget.data.lastMessage.id),
-    ).run().then((_) {
-      if (!mounted) return;
-      _refreshList();
-    });
+    ).run();
+    if (!mounted) return;
+    _refreshList();
   }
 
   @override
@@ -116,7 +117,7 @@ class _ChatTileState extends State<ChatTile> {
             ),
       onTap: () {
         if (selfUsername == null) return;
-        setCurrentAsRead();
+        unawaited(_setCurrentAsRead());
         final view = ChatView(room: widget.data, selfId: selfUsername!, avatar: circleAvatar);
         TalkNavigator.pushSplitView(context, view, overrideToSingleSubScreen: true);
         context.read<ChatBloc>().setToken(widget.data.token);
@@ -125,65 +126,53 @@ class _ChatTileState extends State<ChatTile> {
         if (widget.disableContextActions) return;
         showDialog(context: context, builder: (dialogCtx) => SimpleDialog(
           children: [
-            Visibility(
-              visible: widget.data.unreadMessages > 0,
-              replacement: ListTile(
-                leading: const Icon(Icons.mark_chat_unread_outlined),
-                title: const Text('Als ungelesen markieren'),
-                onTap: () {
-                  SetReadMarker(widget.data.token, false).run().then((_) {
-                    if (mounted) _refreshList();
-                  });
-                  Navigator.of(dialogCtx).pop();
-                },
-              ),
-              child: ListTile(
+            if (widget.data.unreadMessages > 0)
+              AsyncListTile(
                 leading: const Icon(Icons.mark_chat_read_outlined),
                 title: const Text('Als gelesen markieren'),
-                onTap: () {
-                  setCurrentAsRead();
-                  Navigator.of(dialogCtx).pop();
+                onPressed: _setCurrentAsRead,
+              )
+            else
+              AsyncListTile(
+                leading: const Icon(Icons.mark_chat_unread_outlined),
+                title: const Text('Als ungelesen markieren'),
+                onPressed: () async {
+                  await SetReadMarker(widget.data.token, false).run();
+                  if (mounted) _refreshList();
                 },
               ),
-            ),
-            Visibility(
-              visible: widget.data.isFavorite,
-              replacement: ListTile(
-                leading: const Icon(Icons.star_outline),
-                title: const Text('Zu Favoriten hinzufügen'),
-                onTap: () {
-                  SetFavorite(widget.data.token, true).run().then((_) {
-                    if (mounted) _refreshList();
-                  });
-                  Navigator.of(dialogCtx).pop();
-                },
-              ),
-              child: ListTile(
+            if (widget.data.isFavorite)
+              AsyncListTile(
                 leading: const Icon(Icons.stars_outlined),
                 title: const Text('Von Favoriten entfernen'),
-                onTap: () {
-                  SetFavorite(widget.data.token, false).run().then((_) {
-                    if (mounted) _refreshList();
-                  });
-                  Navigator.of(dialogCtx).pop();
+                onPressed: () async {
+                  await SetFavorite(widget.data.token, false).run();
+                  if (mounted) _refreshList();
+                },
+              )
+            else
+              AsyncListTile(
+                leading: const Icon(Icons.star_outline),
+                title: const Text('Zu Favoriten hinzufügen'),
+                onPressed: () async {
+                  await SetFavorite(widget.data.token, true).run();
+                  if (mounted) _refreshList();
                 },
               ),
-            ),
             ListTile(
               leading: const Icon(Icons.delete_outline),
               title: const Text('Konversation verlassen'),
               onTap: () {
+                Navigator.of(dialogCtx).pop();
                 ConfirmDialog(
                   title: 'Chat verlassen',
                   content: 'Du benötigst ggf. eine Einladung um erneut beizutreten.',
-                  confirmButton: 'Löschen',
-                  onConfirm: () {
-                    LeaveRoom(widget.data.token).run().then((_) {
-                      if (mounted) _refreshList();
-                    });
-                    Navigator.of(dialogCtx).pop();
+                  confirmButton: 'Verlassen',
+                  onConfirmAsync: () async {
+                    await LeaveRoom(widget.data.token).run();
+                    if (mounted) _refreshList();
                   },
-                ).asDialog(dialogCtx);
+                ).asDialog(context);
               },
             ),
             DebugTile(dialogCtx).jsonData(widget.data.toJson()),

lib/view/pages/timetable/details/delete_custom_event.dart

@@ -15,9 +15,7 @@ Completer<void> showDeleteCustomEventDialog(BuildContext context, CustomTimetabl
     content: 'Der ${event.rrule.isEmpty ? "Termin" : "Serientermin"} wird unwiederruflich gelöscht.',
     confirmButton: 'Löschen',
     onConfirm: () {
-      bloc.removeCustomEvent(event.id).then(completer.complete).onError((Object error, StackTrace stack) {
-        completer.completeError(error, stack);
-      });
+      bloc.removeCustomEvent(event.id).then(completer.complete).onError(completer.completeError);
     },
   ).asDialog(context);
   return completer;

lib/view/pages/timetable/timetable.dart

@@ -8,6 +8,7 @@ import '../../../state/app/infrastructure/loadableState/view/loadable_state_cons
 import '../../../state/app/modules/timetable/bloc/timetable_bloc.dart';
 import '../../../state/app/modules/timetable/bloc/timetable_state.dart';
 import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
+import '../../../storage/timetable_settings.dart';
 import 'custom_events/custom_event_edit_dialog.dart';
 import 'data/arbitrary_appointment.dart';
 import 'data/lesson_period_schedule.dart';
@@ -30,6 +31,7 @@ class _TimetableState extends State<Timetable> {
 
   List<Appointment>? _cachedAppointments;
   int? _lastDataVersion;
+  TimetableSettings? _lastTimetableSettings;
 
   DateTime _initialDisplayDate() => DateTime.now().add(const Duration(days: 2));
 
@@ -51,18 +53,21 @@ class _TimetableState extends State<Timetable> {
   }
 
   List<Appointment> _appointments(TimetableState state) {
-    if (_cachedAppointments != null && _lastDataVersion == state.dataVersion) {
+    final timetableSettings = context.watch<SettingsCubit>().val().timetableSettings;
+    if (_cachedAppointments != null &&
+        _lastDataVersion == state.dataVersion &&
+        identical(_lastTimetableSettings, timetableSettings)) {
       return _cachedAppointments!;
     }
     _lastDataVersion = state.dataVersion;
+    _lastTimetableSettings = timetableSettings;
 
-    final settings = context.read<SettingsCubit>();
     return _cachedAppointments = TimetableAppointmentFactory(
       lessons: state.getAllKnownLessons().toList(),
       customEvents: state.customEvents?.events ?? const [],
       rooms: state.rooms!,
       subjects: state.subjects!,
-      settings: settings.val().timetableSettings,
+      settings: timetableSettings,
       now: DateTime.now(),
     ).build();
   }

lib/widget/app_progress_indicator.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+
+class AppProgressIndicator extends StatelessWidget {
+  final double size;
+  final double strokeWidth;
+  final Color? color;
+
+  const AppProgressIndicator._({
+    required this.size,
+    required this.strokeWidth,
+    this.color,
+  });
+
+  const AppProgressIndicator.small({Color? color})
+      : this._(size: 16, strokeWidth: 2, color: color);
+
+  const AppProgressIndicator.medium({Color? color})
+      : this._(size: 24, strokeWidth: 2.5, color: color);
+
+  const AppProgressIndicator.large({Color? color})
+      : this._(size: 40, strokeWidth: 3, color: color);
+
+  @override
+  Widget build(BuildContext context) {
+    final resolved = color ?? Theme.of(context).colorScheme.primary;
+    return SizedBox(
+      width: size,
+      height: size,
+      child: CircularProgressIndicator(
+        strokeWidth: strokeWidth,
+        valueColor: AlwaysStoppedAnimation<Color>(resolved),
+      ),
+    );
+  }
+}

lib/widget/async_action_button.dart

@@ -0,0 +1,541 @@
+import 'package:flutter/material.dart';
+
+import '../api/errors/error_mapper.dart';
+import 'app_progress_indicator.dart';
+import 'info_dialog.dart';
+
+Future<bool> runWithErrorDialog(
+  BuildContext context,
+  AsyncActionCallback action, {
+  AsyncErrorBuilder? errorBuilder,
+}) async {
+  try {
+    await action();
+    return true;
+  } catch (e) {
+    if (!context.mounted) return false;
+    final message = errorBuilder != null ? errorBuilder(e) : errorToUserMessage(e);
+    InfoDialog.show(context, message);
+    return false;
+  }
+}
+
+typedef AsyncActionCallback = Future<void> Function();
+typedef AsyncErrorBuilder = String Function(Object error);
+
+class AsyncActionController extends ChangeNotifier {
+  bool _busy = false;
+  String? _error;
+
+  bool get busy => _busy;
+  String? get error => _error;
+
+  Future<bool> run(
+    AsyncActionCallback action, {
+    AsyncErrorBuilder? errorBuilder,
+  }) async {
+    if (_busy) return false;
+    _busy = true;
+    _error = null;
+    notifyListeners();
+    try {
+      await action();
+      _busy = false;
+      notifyListeners();
+      return true;
+    } catch (e) {
+      _busy = false;
+      _error = errorBuilder != null ? errorBuilder(e) : errorToUserMessage(e);
+      notifyListeners();
+      return false;
+    }
+  }
+
+  void clearError() {
+    if (_error == null) return;
+    _error = null;
+    notifyListeners();
+  }
+}
+
+class _AsyncMixin extends StatefulWidget {
+  final AsyncActionCallback? onPressed;
+  final AsyncActionController? controller;
+  final AsyncErrorBuilder? errorBuilder;
+  final void Function(String message)? onError;
+  final VoidCallback? onSuccess;
+  final Widget Function(BuildContext context, bool busy, VoidCallback? handler) builder;
+
+  const _AsyncMixin({
+    required this.onPressed,
+    required this.builder,
+    this.controller,
+    this.errorBuilder,
+    this.onError,
+    this.onSuccess,
+  });
+
+  @override
+  State<_AsyncMixin> createState() => _AsyncMixinState();
+}
+
+class _AsyncMixinState extends State<_AsyncMixin> {
+  late final AsyncActionController _internal;
+  AsyncActionController get _controller => widget.controller ?? _internal;
+
+  @override
+  void initState() {
+    super.initState();
+    if (widget.controller == null) {
+      _internal = AsyncActionController();
+    }
+    _controller.addListener(_onControllerChange);
+  }
+
+  @override
+  void didUpdateWidget(covariant _AsyncMixin oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.controller != widget.controller) {
+      (oldWidget.controller ?? _internal).removeListener(_onControllerChange);
+      _controller.addListener(_onControllerChange);
+    }
+  }
+
+  @override
+  void dispose() {
+    _controller.removeListener(_onControllerChange);
+    if (widget.controller == null) {
+      _internal.dispose();
+    }
+    super.dispose();
+  }
+
+  void _onControllerChange() {
+    if (mounted) setState(() {});
+  }
+
+  Future<void> _trigger() async {
+    final action = widget.onPressed;
+    if (action == null) return;
+    final success = await _controller.run(action, errorBuilder: widget.errorBuilder);
+    if (!mounted) return;
+    if (success) {
+      widget.onSuccess?.call();
+    } else if (widget.onError != null && _controller.error != null) {
+      widget.onError!(_controller.error!);
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final handler = widget.onPressed == null ? null : _trigger;
+    return widget.builder(context, _controller.busy, _controller.busy ? null : handler);
+  }
+}
+
+class AsyncActionButton extends StatelessWidget {
+  final AsyncActionCallback? onPressed;
+  final Widget child;
+  final IconData? icon;
+  final ButtonStyle? style;
+  final AsyncActionController? controller;
+  final AsyncErrorBuilder? errorBuilder;
+  final void Function(String message)? onError;
+  final VoidCallback? onSuccess;
+  final bool showInlineError;
+
+  const AsyncActionButton({
+    required this.onPressed,
+    required this.child,
+    this.icon,
+    this.style,
+    this.controller,
+    this.errorBuilder,
+    this.onError,
+    this.onSuccess,
+    this.showInlineError = true,
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) => _AsyncMixin(
+        onPressed: onPressed,
+        controller: controller,
+        errorBuilder: errorBuilder,
+        onError: onError,
+        onSuccess: onSuccess,
+        builder: (context, busy, handler) {
+          final spinner = AppProgressIndicator.small(
+            color: Theme.of(context).colorScheme.onPrimary,
+          );
+          final content = busy
+              ? Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [spinner, const SizedBox(width: 8), child],
+                )
+              : (icon != null
+                  ? Row(
+                      mainAxisSize: MainAxisSize.min,
+                      children: [Icon(icon), const SizedBox(width: 8), child],
+                    )
+                  : child);
+          final button = ElevatedButton(
+            onPressed: handler,
+            style: style,
+            child: content,
+          );
+          return _withInlineError(context, button);
+        },
+      );
+
+  Widget _withInlineError(BuildContext context, Widget button) {
+    if (!showInlineError) return button;
+    return _InlineErrorWrapper(controller: controller, child: button);
+  }
+}
+
+class AsyncTextButton extends StatelessWidget {
+  final AsyncActionCallback? onPressed;
+  final Widget child;
+  final AsyncActionController? controller;
+  final AsyncErrorBuilder? errorBuilder;
+  final void Function(String message)? onError;
+  final VoidCallback? onSuccess;
+  final bool showInlineError;
+
+  const AsyncTextButton({
+    required this.onPressed,
+    required this.child,
+    this.controller,
+    this.errorBuilder,
+    this.onError,
+    this.onSuccess,
+    this.showInlineError = true,
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) => _AsyncMixin(
+        onPressed: onPressed,
+        controller: controller,
+        errorBuilder: errorBuilder,
+        onError: onError,
+        onSuccess: onSuccess,
+        builder: (context, busy, handler) {
+          final content = busy
+              ? Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    AppProgressIndicator.small(
+                      color: Theme.of(context).colorScheme.primary,
+                    ),
+                    const SizedBox(width: 8),
+                    child,
+                  ],
+                )
+              : child;
+          return _InlineErrorWrapper(
+            controller: controller,
+            child: TextButton(onPressed: handler, child: content),
+          );
+        },
+      );
+}
+
+class AsyncIconButton extends StatelessWidget {
+  final AsyncActionCallback? onPressed;
+  final IconData icon;
+  final Color? color;
+  final String? tooltip;
+  final AsyncActionController? controller;
+  final AsyncErrorBuilder? errorBuilder;
+  final void Function(String message)? onError;
+  final VoidCallback? onSuccess;
+
+  const AsyncIconButton({
+    required this.onPressed,
+    required this.icon,
+    this.color,
+    this.tooltip,
+    this.controller,
+    this.errorBuilder,
+    this.onError,
+    this.onSuccess,
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) => _AsyncMixin(
+        onPressed: onPressed,
+        controller: controller,
+        errorBuilder: errorBuilder,
+        onError: onError,
+        onSuccess: onSuccess,
+        builder: (context, busy, handler) {
+          if (busy) {
+            return Padding(
+              padding: const EdgeInsets.all(12),
+              child: AppProgressIndicator.small(color: color),
+            );
+          }
+          return IconButton(
+            icon: Icon(icon, color: color),
+            tooltip: tooltip,
+            onPressed: handler,
+          );
+        },
+      );
+}
+
+class AsyncFab extends StatelessWidget {
+  final AsyncActionCallback? onPressed;
+  final IconData icon;
+  final Color? backgroundColor;
+  final Color? foregroundColor;
+  final Object? heroTag;
+  final AsyncActionController? controller;
+  final AsyncErrorBuilder? errorBuilder;
+  final void Function(String message)? onError;
+  final VoidCallback? onSuccess;
+  final bool mini;
+
+  const AsyncFab({
+    required this.onPressed,
+    required this.icon,
+    this.backgroundColor,
+    this.foregroundColor,
+    this.heroTag,
+    this.controller,
+    this.errorBuilder,
+    this.onError,
+    this.onSuccess,
+    this.mini = false,
+    super.key,
+  });
+
+  @override
+  Widget build(BuildContext context) => _AsyncMixin(
+        onPressed: onPressed,
+        controller: controller,
+        errorBuilder: errorBuilder,
+        onError: onError,
+        onSuccess: onSuccess,
+        builder: (context, busy, handler) {
+          final fg = foregroundColor ?? Theme.of(context).colorScheme.onPrimary;
+          return FloatingActionButton(
+            heroTag: heroTag,
+            backgroundColor: backgroundColor,
+            foregroundColor: fg,
+            mini: mini,
+            onPressed: handler,
+            child: busy ? AppProgressIndicator.small(color: fg) : Icon(icon),
+          );
+        },
+      );
+}
+
+class AsyncListTile extends StatefulWidget {
+  final AsyncActionCallback onPressed;
+  final Widget? leading;
+  final Widget title;
+  final Widget? subtitle;
+  final bool closeOnSuccess;
+  final VoidCallback? onSuccess;
+  final AsyncErrorBuilder? errorBuilder;
+  final bool enabled;
+
+  const AsyncListTile({
+    required this.onPressed,
+    required this.title,
+    this.leading,
+    this.subtitle,
+    this.closeOnSuccess = true,
+    this.onSuccess,
+    this.errorBuilder,
+    this.enabled = true,
+    super.key,
+  });
+
+  @override
+  State<AsyncListTile> createState() => _AsyncListTileState();
+}
+
+class _AsyncListTileState extends State<AsyncListTile> {
+  final AsyncActionController _controller = AsyncActionController();
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  Future<void> _handleTap() async {
+    final ok = await _controller.run(widget.onPressed, errorBuilder: widget.errorBuilder);
+    if (!mounted) return;
+    if (ok) {
+      widget.onSuccess?.call();
+      if (widget.closeOnSuccess && Navigator.of(context).canPop()) {
+        Navigator.of(context).pop();
+      }
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) => AnimatedBuilder(
+        animation: _controller,
+        builder: (context, _) {
+          final busy = _controller.busy;
+          final err = _controller.error;
+          final leading = busy
+              ? const SizedBox(
+                  width: 24,
+                  height: 24,
+                  child: AppProgressIndicator.small(),
+                )
+              : widget.leading;
+          return Column(
+            mainAxisSize: MainAxisSize.min,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              ListTile(
+                leading: leading,
+                title: widget.title,
+                subtitle: widget.subtitle,
+                enabled: widget.enabled && !busy,
+                onTap: busy ? null : _handleTap,
+              ),
+              if (err != null)
+                Padding(
+                  padding: const EdgeInsets.only(left: 16, right: 16, bottom: 8),
+                  child: Text(
+                    err,
+                    style: TextStyle(color: Theme.of(context).colorScheme.error, fontSize: 13),
+                  ),
+                ),
+            ],
+          );
+        },
+      );
+}
+
+class _InlineErrorWrapper extends StatelessWidget {
+  final AsyncActionController? controller;
+  final Widget child;
+  const _InlineErrorWrapper({required this.controller, required this.child});
+
+  @override
+  Widget build(BuildContext context) {
+    final c = controller;
+    if (c == null) return child;
+    return AnimatedBuilder(
+      animation: c,
+      builder: (context, _) {
+        final err = c.error;
+        return Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.center,
+          children: [
+            child,
+            if (err != null) ...[
+              const SizedBox(height: 8),
+              Text(
+                err,
+                textAlign: TextAlign.center,
+                style: TextStyle(color: Theme.of(context).colorScheme.error, fontSize: 13),
+              ),
+            ],
+          ],
+        );
+      },
+    );
+  }
+}
+
+class AsyncDialogAction extends StatefulWidget {
+  final String confirmLabel;
+  final AsyncActionCallback onConfirm;
+  final String? cancelLabel;
+  final AsyncErrorBuilder? errorBuilder;
+  final ButtonStyle? confirmStyle;
+
+  const AsyncDialogAction({
+    required this.confirmLabel,
+    required this.onConfirm,
+    this.cancelLabel = 'Abbrechen',
+    this.errorBuilder,
+    this.confirmStyle,
+    super.key,
+  });
+
+  @override
+  State<AsyncDialogAction> createState() => _AsyncDialogActionState();
+}
+
+class _AsyncDialogActionState extends State<AsyncDialogAction> {
+  final AsyncActionController _controller = AsyncActionController();
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) => AnimatedBuilder(
+        animation: _controller,
+        builder: (context, _) {
+          final err = _controller.error;
+        return Column(
+          mainAxisSize: MainAxisSize.min,
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: [
+            if (err != null)
+              Padding(
+                padding: const EdgeInsets.only(bottom: 8),
+                child: Text(
+                  err,
+                  textAlign: TextAlign.center,
+                  style: TextStyle(color: Theme.of(context).colorScheme.error, fontSize: 13),
+                ),
+              ),
+            Row(
+              mainAxisAlignment: MainAxisAlignment.end,
+              children: [
+                if (widget.cancelLabel != null)
+                  TextButton(
+                    onPressed: _controller.busy ? null : () => Navigator.of(context).pop(),
+                    child: Text(widget.cancelLabel!),
+                  ),
+                TextButton(
+                  style: widget.confirmStyle,
+                  onPressed: _controller.busy
+                      ? null
+                      : () async {
+                          final ok = await _controller.run(
+                            widget.onConfirm,
+                            errorBuilder: widget.errorBuilder,
+                          );
+                          if (ok && context.mounted) {
+                            Navigator.of(context).pop(true);
+                          }
+                        },
+                  child: _controller.busy
+                      ? Row(
+                          mainAxisSize: MainAxisSize.min,
+                          children: [
+                            AppProgressIndicator.small(
+                              color: Theme.of(context).colorScheme.primary,
+                            ),
+                            const SizedBox(width: 8),
+                            Text(widget.confirmLabel),
+                          ],
+                        )
+                      : Text(widget.confirmLabel),
+                ),
+              ],
+            ),
+          ],
+        );
+        },
+      );
+}

lib/widget/confirm_dialog.dart

@@ -1,14 +1,30 @@
 import 'package:flutter/material.dart';
 import 'package:url_launcher/url_launcher.dart';
 
+import 'async_action_button.dart';
+
 class ConfirmDialog extends StatelessWidget {
   final String title;
   final String content;
   final IconData? icon;
   final String confirmButton;
   final String cancelButton;
-  final void Function() onConfirm;
-  const ConfirmDialog({super.key, required this.title, this.content = '', this.icon, this.confirmButton = 'Ok', this.cancelButton = 'Abbrechen', required this.onConfirm});
+  final void Function()? onConfirm;
+  final AsyncActionCallback? onConfirmAsync;
+  final AsyncErrorBuilder? errorBuilder;
+
+  const ConfirmDialog({
+    super.key,
+    required this.title,
+    this.content = '',
+    this.icon,
+    this.confirmButton = 'Ok',
+    this.cancelButton = 'Abbrechen',
+    this.onConfirm,
+    this.onConfirmAsync,
+    this.errorBuilder,
+  }) : assert(onConfirm != null || onConfirmAsync != null,
+          'ConfirmDialog requires either onConfirm or onConfirmAsync');
 
   void asDialog(BuildContext context) {
     showDialog(context: context, builder: build);
@@ -16,19 +32,32 @@ class ConfirmDialog extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) => AlertDialog(
-      icon: icon != null ? Icon(icon) : null,
-      title: Text(title),
-      content: Text(content),
-      actions: [
-        TextButton(onPressed: () {
-          Navigator.of(context).pop();
-        }, child: Text(cancelButton)),
-        TextButton(onPressed: () {
-          Navigator.of(context).pop();
-          onConfirm();
-        }, child: Text(confirmButton)),
-      ],
-    );
+        icon: icon != null ? Icon(icon) : null,
+        title: Text(title),
+        content: Text(content),
+        actions: onConfirmAsync != null
+            ? [
+                AsyncDialogAction(
+                  confirmLabel: confirmButton,
+                  cancelLabel: cancelButton,
+                  onConfirm: onConfirmAsync!,
+                  errorBuilder: errorBuilder,
+                ),
+              ]
+            : [
+                TextButton(
+                  onPressed: () => Navigator.of(context).pop(),
+                  child: Text(cancelButton),
+                ),
+                TextButton(
+                  onPressed: () {
+                    Navigator.of(context).pop();
+                    onConfirm!();
+                  },
+                  child: Text(confirmButton),
+                ),
+              ],
+      );
 
   static void openBrowser(BuildContext context, String url) {
     showDialog(