How do I check if the Flutter application is in the foreground or not?

Question

I don\'t want to show notification when the app is in foreground. How can I check live state of my app?

Answer 1

Simply create a bool variable which will keep track of all your background/foreground stuff.

Full code:

class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
  // This variable will tell you whether the application is in foreground or not. 
  bool _isInForeground = true;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }
  
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);
    _isInForeground = state == AppLifecycleState.resumed;
  }

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

  @override
  Widget build(BuildContext context) => Scaffold();
}

Answer 2

My Answer may be late but may be helpful for someone. I also faced this problem there is a plugin which works on both android and ios

https://pub.dev/packages/flutter_app_lock

Where you can put you desired lockscreen also it is very flexible.

Hope someone who stuck like me can get this easily done.

Answer 3

To extend on the above answer, you can use a switch statement to make it nice and neat:

 @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    switch(state){
      case AppLifecycleState.resumed:
        print("app in resumed");
        break;
      case AppLifecycleState.inactive:
        print("app in inactive");
        break;
      case AppLifecycleState.paused:
        print("app in paused");
        break;
      case AppLifecycleState.detached:
        print("app in detached");
        break;
    }
}

Answer 4

In your State<...> class you need to implement WidgetsBindingObserver interface and listen for widget state changes. Something like this:

class _MyHomePageState extends State<MyHomePage> with WidgetsBindingObserver {
  AppLifecycleState _notification; 
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    setState(() {
      _notification = state;
    });
  }

  @override
  initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    ...
  }

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

Then when you want to know what is the state, check _notification.index property. _notification == null => no state changes happened, 0 - resumed, 1 - inactive, 2 - paused.