detect "returned to the app" , "App went to background" (didChangeAppLifecycleState) (iOS & Android work)

class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {

 @override

void initState() {
  super.initState();
  WidgetsBinding.instance!.addObserver(this);
}

// ...

@override
void dispose() {
  WidgetsBinding.instance!.removeObserver(this);
  super.dispose();
}

@override
void didChangeAppLifecycleState(AppLifecycleState state) {
  super.didChangeAppLifecycleState(state);
  print('AppLifecycleState: $state');
  if (state == AppLifecycleState.resumed) {
    // User has returned to the app (app is in the foreground and active)
    print('myState: User returned to the app!');
    // Perform actions here, e.g., refresh data, show a message, etc.
  } else if (state == AppLifecycleState.paused) {
    // App is in the background
    print('myState: App went to background');
  } else if (state == AppLifecycleState.inactive) {
    // App is inactive (e.g., a phone call came in, or app is about to go to background)
    print('myState: App is inactive');
  }
}