initial commit

lib/screens/monthly_view.dart

@@ -52,16 +52,32 @@ class _MonthlyViewState extends State<MonthlyView> {
     DateTime.sunday: 0,
   };
 
-  late final ScrollController _hCtrl;
-  late final ScrollController _vCtrl;
+  // Scroll-Controller
+  late final ScrollController _hHeaderCtrl; // Header (nur mitgeführt)
+  late final ScrollController _hBodyCtrl;   // Body (führend)
+  late final ScrollController _vCtrl;       // Body vertikal
+  bool _syncingH = false;
 
   @override
   void initState() {
     super.initState();
     final now = DateTime.now();
     _monthStart = DateTime(now.year, now.month, 1);
-    _hCtrl = ScrollController();
+
+    _hHeaderCtrl = ScrollController();
+    _hBodyCtrl = ScrollController();
     _vCtrl = ScrollController();
+
+    // Body scrollt -> Header folgt
+    _hBodyCtrl.addListener(() {
+      if (_syncingH) return;
+      _syncingH = true;
+      if (_hHeaderCtrl.hasClients) {
+        _hHeaderCtrl.jumpTo(_hBodyCtrl.offset);
+      }
+      _syncingH = false;
+    });
+
     _client = http.Client();
     _bookingApi = BookingApi(client: _client);
     _dailyApi = DailyWorkingApi(client: _client);
@@ -76,7 +92,8 @@ class _MonthlyViewState extends State<MonthlyView> {
     for (final c in _controllers.values) {
       c.dispose();
     }
-    _hCtrl.dispose();
+    _hHeaderCtrl.dispose();
+    _hBodyCtrl.dispose();
     _vCtrl.dispose();
     _client.close();
     super.dispose();
@@ -235,42 +252,34 @@ class _MonthlyViewState extends State<MonthlyView> {
           ),
         ),
 
-      // FIXIERTE KOPFZEILE
-      Scrollbar(
-        controller: _hCtrl,
-        notificationPredicate: (n) => n.metrics.axis == Axis.horizontal,
-        thumbVisibility: true,
-        child: SingleChildScrollView(
-          controller: _hCtrl,
-          scrollDirection: Axis.horizontal,
-          child: ConstrainedBox(
-            constraints: BoxConstraints(minWidth: _tableMinWidth),
-            child: DataTableTheme(
-              data: DataTableThemeData(
-                headingRowHeight: 30,
-                columnSpacing: 10,
-                headingTextStyle: const TextStyle(fontWeight: FontWeight.w700).copyWith(
-                  fontSize: _fontSize,
-                ),
-              ),
-              child: DataTable(
-                showCheckboxColumn: false,
-                columns: headerColumns,
-                rows: const <DataRow>[],
+      // FIXIERTE KOPFZEILE (mitgeführt, nicht interaktiv)
+      SingleChildScrollView(
+        controller: _hHeaderCtrl,
+        physics: const NeverScrollableScrollPhysics(),
+        scrollDirection: Axis.horizontal,
+        child: ConstrainedBox(
+          constraints: BoxConstraints(minWidth: _tableMinWidth),
+          child: DataTableTheme(
+            data: DataTableThemeData(
+              headingRowHeight: 30,
+              columnSpacing: 10,
+              headingTextStyle: const TextStyle(fontWeight: FontWeight.w700).copyWith(
+                fontSize: _fontSize,
               ),
             ),
+            child: const _HeaderOnlyDataTable(),
           ),
         ),
       ),
 
-      // BODY
+      // BODY (horiz. & vert. Scroll; horizontale Scrollbar hier)
       Expanded(
         child: Scrollbar(
-          controller: _hCtrl,
+          controller: _hBodyCtrl,
           notificationPredicate: (n) => n.metrics.axis == Axis.horizontal,
           thumbVisibility: true,
           child: SingleChildScrollView(
-            controller: _hCtrl,
+            controller: _hBodyCtrl,
             padding: const EdgeInsets.only(bottom: 16),
             scrollDirection: Axis.horizontal,
             child: ConstrainedBox(
@@ -283,7 +292,7 @@ class _MonthlyViewState extends State<MonthlyView> {
                   controller: _vCtrl,
                   child: DataTableTheme(
                     data: const DataTableThemeData(
-                      headingRowHeight: 0,
+                      headingRowHeight: 0, // Header im Body ausblenden
                       dataRowMinHeight: 30,
                       dataRowMaxHeight: 34,
                       columnSpacing: 10,
@@ -498,6 +507,15 @@ class _MonthlyViewState extends State<MonthlyView> {
     return cells;
   }
 
+  // kleines Mono-Text-Widget für Zahlen
+  Widget _monoSmall(String s) => Text(
+        s,
+        style: const TextStyle(
+          fontSize: _fontSize,
+          fontFeatures: [FontFeature.tabularFigures()],
+        ),
+      );
+
   Widget _codeDropdown(int dayIndex, WorkDay day) {
     final value = day.code;
     final values = <String?>[null, ...kAbsenceCodes];
@@ -672,14 +690,6 @@ class _MonthlyViewState extends State<MonthlyView> {
     );
   }
 
-Widget _monoSmall(String s) => Text(
-  s,
-  style: const TextStyle(
-    fontSize: _fontSize,
-    fontFeatures: [FontFeature.tabularFigures()],
-  ),
-);
-
   TextAlign _toTextAlign(Alignment a) {
     if (a == Alignment.centerRight) return TextAlign.right;
     if (a == Alignment.centerLeft) return TextAlign.left;
@@ -687,6 +697,23 @@ Widget _monoSmall(String s) => Text(
   }
 }
 
+/// Minimaler Header-Table, damit die Kopfzeile fixiert bleiben kann.
+/// Nutzt die gleichen Spalten wie der Body, aber ohne Rows.
+class _HeaderOnlyDataTable extends StatelessWidget {
+  const _HeaderOnlyDataTable();
+
+  @override
+  Widget build(BuildContext context) {
+    final state = context.findAncestorStateOfType<_MonthlyViewState>()!;
+    final cols = state._buildColumns();
+    return DataTable(
+      showCheckboxColumn: false,
+      columns: cols,
+      rows: const <DataRow>[],
+    );
+  }
+}
+
 class _MonthHeader extends StatelessWidget {
   final DateTime month;
   final VoidCallback onPrev;