implemented scheduled updates for widgets

lib/main.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 import 'dart:developer';
 import 'dart:io';
 
+import 'package:background_fetch/background_fetch.dart';
 import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_messaging/firebase_messaging.dart';
 import 'package:flutter/foundation.dart';
@@ -17,6 +18,7 @@ import 'package:provider/provider.dart';
 
 import 'api/mhsl/breaker/getBreakers/getBreakersResponse.dart';
 import 'app.dart';
+import 'background_tasks/scheduledTask.dart';
 import 'firebase_options.dart';
 import 'model/accountData.dart';
 import 'model/accountModel.dart';
@@ -84,6 +86,8 @@ Future<void> main() async {
         child: const Main(),
       )
   );
+
+  BackgroundFetch.registerHeadlessTask(ScheduledTask.headless);
 }
 
 class Main extends StatefulWidget {
@@ -111,6 +115,7 @@ class _MainState extends State<Main> {
       Provider.of<BreakerProps>(context, listen: false).run();
     });
 
+    ScheduledTask.configure();
     super.initState();
   }
 
@@ -146,7 +151,7 @@ class _MainState extends State<Main> {
                   child: Consumer<AccountModel>(
                     builder: (context, accountModel, child) {
                       switch(accountModel.state) {
-                        case AccountModelState.loggedIn: return const App();
+                        case AccountModelState.loggedIn: return App(key: App.appContext);
                         case AccountModelState.loggedOut: return const Login();
                         case AccountModelState.undefined: return const PlaceholderView(icon: Icons.timer, text: 'Daten werden geladen');
                       }