further improved accessibility across the application and add tooltips to action buttons

lib/view/login/widgets/login_error_banner.dart

@@ -18,6 +18,14 @@ class LoginErrorBanner extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final showDetails = details != null
+        ? () => InfoDialog.show(
+            context,
+            details!,
+            copyable: true,
+            title: 'Fehlerdetails',
+          )
+        : null;
     return AnimatedSize(
       duration: const Duration(milliseconds: 180),
       curve: Curves.easeOut,
@@ -25,18 +33,20 @@ class LoginErrorBanner extends StatelessWidget {
           ? const SizedBox(height: 0, width: double.infinity)
           : Padding(
               padding: const EdgeInsets.only(top: 14),
+              child: Semantics(
+                button: showDetails != null,
+                label: showDetails != null
+                    ? '${message!}, Fehlerdetails anzeigen'
+                    : message,
+                onTap: showDetails,
+                child: ExcludeSemantics(
                   child: Material(
-                color: theme.colorScheme.errorContainer.withValues(alpha: 0.6),
+                    color: theme.colorScheme.errorContainer.withValues(
+                      alpha: 0.6,
+                    ),
                     borderRadius: BorderRadius.circular(12),
                     child: InkWell(
-                  onTap: details != null
+                      onTap: showDetails,
-                      ? () => InfoDialog.show(
-                          context,
-                          details!,
-                          copyable: true,
-                          title: 'Fehlerdetails',
-                        )
-                      : null,
                       borderRadius: BorderRadius.circular(12),
                       child: Padding(
                         padding: const EdgeInsets.symmetric(
@@ -76,6 +86,8 @@ class LoginErrorBanner extends StatelessWidget {
                     ),
                   ),
                 ),
+              ),
+            ),
     );
   }
 }

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

@@ -23,6 +23,8 @@ class FilesSortActions extends StatelessWidget {
       mainAxisSize: MainAxisSize.min,
       children: [
         PopupMenuButton<bool>(
+          tooltip:
+              'Sortierrichtung: ${ascending ? 'aufsteigend' : 'absteigend'}',
           icon: Icon(
             ascending ? Icons.text_rotate_up : Icons.text_rotation_down,
           ),
@@ -47,6 +49,8 @@ class FilesSortActions extends StatelessWidget {
           onSelected: onDirectionChanged,
         ),
         PopupMenuButton<SortOption>(
+          tooltip:
+              'Sortieren nach: ${SortOptions.getOption(currentSort).displayName}',
           icon: const Icon(Icons.sort),
           itemBuilder: (context) => SortOptions.options.keys
               .map(

lib/view/pages/grade_averages/grade_averages_view.dart

@@ -35,6 +35,8 @@ class GradeAveragesView extends StatelessWidget {
                 ),
               ),
               PopupMenuButton<bool>(
+                tooltip:
+                    'Notensystem: ${bloc.isMiddleSchool() ? 'Realschule' : 'Oberstufe'}',
                 initialValue: bloc.isMiddleSchool(),
                 icon: const Icon(Icons.more_horiz),
                 itemBuilder: (context) => [true, false]

lib/view/pages/holidays/holidays_view.dart

@@ -43,6 +43,8 @@ class HolidaysView extends StatelessWidget {
               onPressed: showDisclaimer,
             ),
             PopupMenuButton<bool>(
+              tooltip:
+                  'Vergangene Ferien ${bloc.showPastHolidays() ? 'ausblenden' : 'anzeigen'}',
               initialValue: bloc.showPastHolidays(),
               icon: const Icon(Icons.history),
               itemBuilder: (context) => [true, false]
@@ -82,9 +84,7 @@ class HolidaysView extends StatelessWidget {
                 text: 'Keine Schulferien verfügbar',
               );
             }
-            return ListViewUtil.fromList<McHoliday>(
+            return ListViewUtil.fromList<McHoliday>(holidays, (holiday) {
-            holidays,
-            (holiday) {
               String holidayYear() {
                 final startYear = holiday.startDate.year;
                 final endYear = holiday.endDate.year;
@@ -94,9 +94,7 @@ class HolidaysView extends StatelessWidget {
 
               return ListTile(
                 leading: const CenteredLeading(Icon(Icons.calendar_month)),
-                title: Text(
+                title: Text('${holiday.longName} ${holidayYear()}'),
-                  '${holiday.longName} ${holidayYear()}',
-                ),
                 subtitle: Text(
                   '${holiday.startDate.formatDate()} - ${holiday.endDate.formatDate()}',
                 ),
@@ -148,8 +146,7 @@ class HolidaysView extends StatelessWidget {
                 ),
                 trailing: const Icon(Icons.arrow_right),
               );
-            },
+            });
-          );
           },
         ),
       );

lib/view/pages/marianum_dates/marianum_dates_view.dart

@@ -32,8 +32,9 @@ class MarianumDatesView extends StatelessWidget {
   }
 
   @override
-  Widget build(BuildContext context) =>
+  Widget build(
-      BlocModule<MarianumDatesBloc, LoadableState<MarianumDatesState>>(
+    BuildContext context,
+  ) => BlocModule<MarianumDatesBloc, LoadableState<MarianumDatesState>>(
     create: (context) => MarianumDatesBloc(),
     autoRebuild: true,
     child: (context, bloc, state) => Scaffold(
@@ -41,6 +42,8 @@ class MarianumDatesView extends StatelessWidget {
         title: const Text('Marianum Termine'),
         actions: [
           PopupMenuButton<bool>(
+            tooltip:
+                'Vergangene Termine ${bloc.showPastEvents() ? 'ausblenden' : 'anzeigen'}',
             initialValue: bloc.showPastEvents(),
             icon: const Icon(Icons.history),
             itemBuilder: (context) => [true, false]
@@ -57,9 +60,7 @@ class MarianumDatesView extends StatelessWidget {
                           color: Theme.of(context).colorScheme.onSurface,
                         ),
                         const SizedBox(width: 15),
-                            Text(
+                        Text(e ? 'Alle anzeigen' : 'Nur zukünftige anzeigen'),
-                              e ? 'Alle anzeigen' : 'Nur zukünftige anzeigen',
-                            ),
                       ],
                     ),
                   ),

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

@@ -91,7 +91,14 @@ class _ChatTileState extends State<ChatTile> {
           : null,
       leading: Stack(
         children: [
-          circleAvatar,
+          // Der Name steht bereits im Titel der Zeile – das Avatarbild selbst
+          // muss der Screenreader nicht ansagen. Nur bei Gruppen ist der
+          // Hinweis „Gruppe" nützlich (sonst nicht vom Einzelchat zu
+          // unterscheiden).
+          Semantics(
+            label: isGroup ? A11yLabels.group : null,
+            child: ExcludeSemantics(child: circleAvatar),
+          ),
           Visibility(
             visible: widget.data.isFavorite,
             child: Positioned(

lib/view/pages/timetable/timetable.dart

@@ -106,6 +106,10 @@ class _TimetableState extends State<Timetable> {
         .canViewForeignTimetables;
     return Scaffold(
       appBar: AppBar(
+        // Der Kalender scrollt nicht (nur ziehen/reloaden), aber seine internen
+        // Scrollables feuern ScrollNotifications, die sonst den Material-3
+        // "scrolled under"-Farbwechsel der AppBar dauerhaft auslösen.
+        notificationPredicate: (_) => false,
         title: const Text('Stunden & Vertretungsplan'),
         actions: [
           IconButton(
@@ -114,6 +118,7 @@ class _TimetableState extends State<Timetable> {
             onPressed: atToday ? null : _jumpToToday,
           ),
           PopupMenuButton<_CalendarAction>(
+            tooltip: 'Kalendereinträge',
             icon: const Icon(Icons.edit_calendar_outlined),
             onSelected: _onAction,
             itemBuilder: (_) => const [
@@ -176,6 +181,9 @@ class _TimetableState extends State<Timetable> {
         .canViewForeignTimetables;
     return Scaffold(
       appBar: AppBar(
+        // Siehe _buildOwnPlan: den scroll-under-Farbwechsel unterdrücken, weil
+        // der Kalender nicht scrollt, aber ScrollNotifications feuert.
+        notificationPredicate: (_) => false,
         title: const Text('Stunden & Vertretungsplan'),
         actions: [
           IconButton(
@@ -285,7 +293,9 @@ class _ViewingBanner extends StatelessWidget {
             ),
             compactButton(
               icon: isFavorite ? Icons.star : Icons.star_border,
-              tooltip: isFavorite ? 'Favorit entfernen' : 'Als Favorit markieren',
+              tooltip: isFavorite
+                  ? 'Favorit entfernen'
+                  : 'Als Favorit markieren',
               onPressed: () => _toggleFavorite(context),
             ),
             const SizedBox(width: 4),

lib/view/pages/timetable/widgets/calendar/week_grid.dart

@@ -34,7 +34,15 @@ class _WeekGrid extends StatelessWidget {
     return Row(
       crossAxisAlignment: CrossAxisAlignment.stretch,
       children: [
-        _PeriodRuler(schedule: schedule, layout: layout, width: rulerWidth),
+        // Reine Orientierungshilfe – der Screenreader soll die Zeitleiste nicht
+        // vorlesen; jede Termin-Kachel trägt ihre Uhrzeit selbst im Label.
+        ExcludeSemantics(
+          child: _PeriodRuler(
+            schedule: schedule,
+            layout: layout,
+            width: rulerWidth,
+          ),
+        ),
         for (var d = 0; d < 5; d++)
           Expanded(
             child: _DayColumn(
@@ -279,9 +287,25 @@ class _DayColumn extends StatelessWidget {
     final isTablet = MediaQuery.of(context).size.shortestSide >= 600;
     final laidOut = assignLanes(dayAppointments, maxLanes: isTablet ? 3 : 2);
 
-    return GestureDetector(
+    final dayName = DateFormat(
+      'EEEE',
+      Localizations.localeOf(context).toString(),
+    ).format(date);
+    final headerLabel = isToday
+        ? '$dayName, ${date.formatDateShort()}, ${A11yLabels.today}'
+        : '$dayName, ${date.formatDateShort()}';
+
+    // container + OrdinalSortKey ⇒ der Screenreader liest Tag für Tag (Mo→Fr),
+    // jeden Tag vollständig, statt zeilenweise quer über alle Spalten. Der
+    // Header steckt als erstes Element in der Spalte, damit „Montag: …" vor den
+    // Stunden angesagt wird.
+    return Semantics(
+      container: true,
+      sortKey: OrdinalSortKey(date.weekday.toDouble()),
+      child: GestureDetector(
         behavior: HitTestBehavior.translucent,
-      onLongPressStart: (details) => _handleLongPress(details, dayAppointments),
+        onLongPressStart: (details) =>
+            _handleLongPress(details, dayAppointments),
         child: DecoratedBox(
           decoration: BoxDecoration(
             color: isToday ? theme.colorScheme.primary.withAlpha(14) : null,
@@ -298,6 +322,16 @@ class _DayColumn extends StatelessWidget {
               return Stack(
                 clipBehavior: Clip.none,
                 children: [
+                  Positioned(
+                    top: 0,
+                    left: 0,
+                    right: 0,
+                    child: Semantics(
+                      header: true,
+                      label: headerLabel,
+                      child: const SizedBox(height: 1),
+                    ),
+                  ),
                   for (final period in schedule.periods)
                     Positioned(
                       top: layout.topOf(period),
@@ -352,8 +386,11 @@ class _DayColumn extends StatelessWidget {
                         ),
                         LaidOutOverflow(:final appointments) => Semantics(
                           button: true,
-                        label: A11yLabels.moreAppointments(appointments.length),
+                          label: A11yLabels.moreAppointments(
-                        onTap: () => _showOverflowSheet(context, appointments),
+                            appointments.length,
+                          ),
+                          onTap: () =>
+                              _showOverflowSheet(context, appointments),
                           child: ExcludeSemantics(
                             child: GestureDetector(
                               behavior: HitTestBehavior.opaque,
@@ -379,6 +416,7 @@ class _DayColumn extends StatelessWidget {
             },
           ),
         ),
+      ),
     );
   }
 }

lib/view/pages/timetable/widgets/custom_workweek_calendar.dart

@@ -9,6 +9,7 @@ import 'dart:async';
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/semantics.dart';
 import 'package:intl/intl.dart';
 import 'package:syncfusion_flutter_calendar/calendar.dart';
 
@@ -103,11 +104,7 @@ class CustomWorkWeekCalendarState extends State<CustomWorkWeekCalendar> {
     final newTotalWeeks =
         newLastMonday.difference(newFirstMonday).inDays ~/ 7 + 1;
     final visibleWeekStart = _firstMonday.addDays(_currentWeekIndex * 7);
-    final newIndex = visibleWeekStart
+    final newIndex = visibleWeekStart.difference(newFirstMonday).inDays ~/ 7;
-        .difference(newFirstMonday)
-        .inDays
-        ~/
-        7;
     final clampedIndex = newIndex.clamp(0, newTotalWeeks - 1);
     final oldController = _pageController;
     _pageController = PageController(initialPage: clampedIndex);
@@ -167,6 +164,10 @@ class CustomWorkWeekCalendarState extends State<CustomWorkWeekCalendar> {
                 child: child,
               ),
             ),
+            // Die visuelle „MO/14"-Leiste ist für den Screenreader unbrauchbar;
+            // die Tag-Info wird stattdessen als Header in jede Tagesspalte
+            // eingehängt (siehe _DayColumn).
+            child: ExcludeSemantics(
               child: _DayHeaderStrip(
                 key: ValueKey(visibleWeekStart),
                 weekStart: visibleWeekStart,
@@ -175,6 +176,7 @@ class CustomWorkWeekCalendarState extends State<CustomWorkWeekCalendar> {
               ),
             ),
           ),
+        ),
         ClipRect(
           child: AnimatedSize(
             duration: const Duration(milliseconds: 320),

lib/widget/a11y/a11y_labels.dart

@@ -16,15 +16,17 @@ abstract final class A11yLabels {
   static const draft = 'Entwurf';
   static const yourReaction = 'deine Reaktion';
 
-  // Bilder
+  // Bilder / Kontakte
   static const profilePicture = 'Profilbild';
   static const groupPicture = 'Gruppenbild';
+  static const group = 'Gruppe';
   static const roomPlan = 'Raumplan der Schule als Grafik';
 
   // Stundenplan
   static const cancelled = 'Ausfall';
   static const breakTime = 'Pause';
   static const allDay = 'Ganztägig';
+  static const today = 'heute';
 
   /// Beschreibt eine Stundenplan-Kachel für den Screenreader, z.B.
   /// „Mathe, Raum 101, 08:00–08:45, Ausfall". Zeilenumbrüche in [location]

lib/widget/details_bottom_sheet.dart

@@ -22,6 +22,10 @@ Future<void> showDetailsBottomSheet(
         padding: EdgeInsets.only(
           bottom: 16 + MediaQuery.viewInsetsOf(sheetContext).bottom,
         ),
+        // Ohne dieses innere Material malt ListTile-Ink aufs Sheet-Material
+        // außerhalb des Scrollbereichs und stretcht beim Overscroll nicht mit.
+        child: Material(
+          type: MaterialType.transparency,
           child: Column(
             mainAxisSize: MainAxisSize.min,
             crossAxisAlignment: CrossAxisAlignment.stretch,
@@ -32,5 +36,6 @@ Future<void> showDetailsBottomSheet(
           ),
         ),
       ),
+    ),
   );
 }

lib/widget/downloads/download_tray.dart

@@ -154,7 +154,8 @@ class _DownloadTrayHostState extends State<DownloadTrayHost>
   /// The chip only shows when there's something the inline UI can't already
   /// convey: multiple downloads, a finished/failed one (no inline progress
   /// left), or a lone download whose originating screen the user has left.
-  bool _shouldShowChip(List<DownloadJob> jobs, int epoch) => shouldShowDownloadChip(
+  bool _shouldShowChip(List<DownloadJob> jobs, int epoch) =>
+      shouldShowDownloadChip(
         sheetOpen: _sheetOpen,
         jobCount: jobs.length,
         anySurfaced: jobs.any(
@@ -311,7 +312,12 @@ class _TrayChip extends StatelessWidget {
         label = doneCount == 1 ? 'Download fertig' : '$doneCount fertig';
       }
 
-      return Material(
+      return Semantics(
+        button: true,
+        label: '$label, Downloads anzeigen',
+        onTap: onTap,
+        child: ExcludeSemantics(
+          child: Material(
             color: colors.surfaceContainerHigh,
             elevation: 4,
             borderRadius: BorderRadius.circular(24),
@@ -320,7 +326,10 @@ class _TrayChip extends StatelessWidget {
               borderRadius: BorderRadius.circular(24),
               onTap: onTap,
               child: Padding(
-            padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
+                padding: const EdgeInsets.symmetric(
+                  horizontal: 16,
+                  vertical: 10,
+                ),
                 child: Row(
                   mainAxisSize: MainAxisSize.min,
                   children: [
@@ -337,11 +346,17 @@ class _TrayChip extends StatelessWidget {
                       ),
                     ),
                     const SizedBox(width: 8),
-                Icon(Icons.expand_less, size: 20, color: colors.onSurfaceVariant),
+                    Icon(
+                      Icons.expand_less,
+                      size: 20,
+                      color: colors.onSurfaceVariant,
+                    ),
                   ],
                 ),
               ),
             ),
+          ),
+        ),
       );
     },
   );

lib/widget/file_viewer.dart

@@ -186,6 +186,7 @@ class _FileViewerState extends State<FileViewer> {
       ...actions,
       if (showActionsMenu)
         PopupMenuButton<FileViewingActions>(
+          tooltip: 'Dateiaktionen',
           onSelected: _handleAction,
           itemBuilder: (context) => _availableActions()
               .map(
@@ -282,8 +283,10 @@ class _FileViewerState extends State<FileViewer> {
     ),
   );
 
-  Widget _buildPdfView() =>
+  Widget _buildPdfView() => Scaffold(
-      Scaffold(appBar: _appbar(), body: DeferredPdfViewer(path: widget.path));
+    appBar: _appbar(),
+    body: DeferredPdfViewer(path: widget.path),
+  );
 
   Widget _buildVideoView() => Scaffold(
     appBar: _appbar(),