const tag = "ScheduleTest";

class ScheduleTestPage1 extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Center(
            child: Container(
              width: 50,
              height: 50,
              child: CircularProgressIndicator(),
            ),
          ),
          FlatButton(
              onPressed: () {
                Navigator.of(context).push(MaterialPageRoute(builder: (context) {
                  return ScheduleTestPage2();
                })).then((value) {
                  SchedulerBinding.instance.scheduleTask(() {
                    print("$tag>>>>>>scheduleTask1");
                  }, Priority.touch);

                  Future.delayed(Duration(seconds: 1), () {
                    SchedulerBinding.instance.scheduleTask(() {
                      print("$tag>>>>>>scheduleTask2");
                    }, Priority.touch);
                  });
                });
              },
              child: Text("click me "))
        ],
      ),
    );
  }
}

class ScheduleTestPage2 extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _ScheduleTest2State();
  }
}

class _ScheduleTest2State extends State<ScheduleTestPage2> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Container(
          width: 100,
          height: 50,
          child: FlatButton(
            onPressed: () {
              Navigator.of(context).pop();
            },
            child: Text("Back"),
          ),
        ),
      ),
    );
  }

  @override
  void dispose() {
    super.dispose();
    SchedulerBinding.instance.scheduleTask(() {
      print("$tag>>>>>> call ScheduleTestPage2 dispose");
      // do something such as Exception .    throw Exception("Exception Test");
    }, Priority.idle);
  }
}