Limit timetable scrolling so no errors occur

lib/model/timetable/timetableProps.dart

@@ -105,4 +105,17 @@ class TimetableProps extends DataHolder {
       notifyListeners();
     }
   }
+
+  void resetWeek()  {
+    error = null;
+    notifyListeners();
+
+    DateTime queryWeek = DateTime.now().add(const Duration(days: 2));
+
+    startDate = getDate(queryWeek.subtract(Duration(days: queryWeek.weekday - 1)));
+    endDate = getDate(queryWeek.add(Duration(days: DateTime.daysPerWeek - queryWeek.weekday)));
+
+    run();
+    notifyListeners();
+  }
 }

lib/view/pages/timetable/timetable.dart

@@ -72,6 +72,12 @@ class _TimetableState extends State<Timetable> {
             return PlaceholderView(
               icon: Icons.calendar_month,
               text: "Webuntis error: ${value.error.toString()}",
+              button: TextButton(
+                child: const Text("Neu laden"),
+                onPressed: () {
+                  Provider.of<TimetableProps>(context, listen: false).resetWeek();
+                },
+              ),
             );
           }
 
@@ -90,6 +96,9 @@ class _TimetableState extends State<Timetable> {
               view: CalendarView.workWeek,
               dataSource: _buildTableEvents(value),
 
+              maxDate: DateTime.now().add(const Duration(days: 7)),
+              minDate: DateTime.now().subtract(const Duration (days: 14)),
+
               controller: controller,
 
               onViewChanged: (ViewChangedDetails details) {

lib/widget/placeholderView.dart

@@ -3,7 +3,8 @@ import 'package:flutter/material.dart';
 class PlaceholderView extends StatelessWidget {
   final IconData icon;
   final String text;
-  const PlaceholderView({Key? key, required this.icon, required this.text}) : super(key: key);
+  final Widget? button;
+  const PlaceholderView({Key? key, required this.icon, required this.text, this.button}) : super(key: key);
 
   @override
   Widget build(BuildContext context) {
@@ -25,6 +26,8 @@ class PlaceholderView extends StatelessWidget {
                 ),
                 textAlign: TextAlign.center,
               ),
+              const SizedBox(height: 30),
+              if(button != null) button!,
             ],
           ),
         ),