Flutter Isolate doesn't go do setState after navigate to a other page and back

Question

Hello I have a badge with a counter and whenever I start my Android Alarm Manager it should increase the counter and also update the UI live. I do this with Isolate. Everything works fine but when I go to a new page route and then go back the SetState is not executed anymore. Where is my error?

  int _counter = 0;

  String isolateName = 'isolate';
  final ReceivePort port = ReceivePort();
  static SendPort uiSendPort;


  @override
  void initState() {
    super.initState();
    AndroidAlarmManager.initialize();

    IsolateNameServer.registerPortWithName(
      port.sendPort,
      isolateName,
    );

    port.listen((_) async => await _incrementCounter());
  }

  Future<void> _incrementCounter() async {
    print('Increment counter!');

    // Ensure we've loaded the updated count from the background isolate.
    await prefs.reload();

    if (!mounted) return;
    setState(() {
      print("geht in die SetState");
      _counter++;
    });
  }

///
///This is in my Callback for my Android Alarm Manager...
          final prefs = await SharedPreferences.getInstance();
          int currentCount = prefs.getInt(countKey) ?? 0;
          await prefs.setInt(countKey, currentCount + 1);

          // This will be null if we're running in the background.
          uiSendPort ??= IsolateNameServer.lookupPortByName('isolate');
          uiSendPort?.send(null);

Solution

initState is not called again after returning, try to force the function you want after returning

something like that

Navigator.of(context)
  .push(MaterialPageRoute(
     builder: (context) => YourScreen№2(),
  ))
  .then((value) {
    Foo() <- your func
  });

Comments

[tyler.morton]

Thank you for your answer. What do you mean by force the function after returning?

[novol]

I did edit answer

[novol]

I mean this code in initState void initState() { super.initState(); AndroidAlarmManager.initialize(); IsolateNameServer.registerPortWithName( port.sendPort, isolateName, ); port.listen((_) async => await _incrementCounter()); }

[tyler.morton]

Okay thank you that worked but just with Navigator.of(context).push. Is it at also possible to get the same result with Navigator.pushAndRemoveUntil(context, MaterialPageRoute(builder: (context) => My2Site(),),(_) => false); ?

[novol]

seems ye, more here api.flutter.dev/flutter/widgets/Navigator/…

[novol]

But why delete the previous screens if you want to return to them?