How to execute code before app exit flutter

Question

I want to detect when a user quit my app and execute some code before but I don\'t know how to do this. I tried to use this package: https://pub.dev/packages/flutter_lifecyc

Answer 1

What about putting your main/home/top Scaffold widget inside a WillPopScope?

class MyGreatestApp extends StatefulWidget {
  @override
  _MyGreatestAppState createState() => _MyGreatestAppState();
}

class _MyGreatestAppState extends State {
  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      child: Scaffold(...),
      onWillPop: _doNastyStuffsBeforeExit,
    );
  }

  Future _doNastyStuffsBeforeExit() async{
    // Since this is an async method, anything you do here will not block UI thread
    // So you should inform user there is a work need to do before exit, I recommend SnackBar

    // Do your pre-exit works here...

    // also, you must decide whether the app should exit or not after the work above, by returning a future boolean value:

    return Future.value(true); // this will close the app,
    return Future.value(false); // and this will prevent the app from exiting (by tapping the back button on home route)
  }
}