[Flutter] AppLifecycleState

The observable lifecycle events are:

• inactive — The application is in an inactive state and is not receiving user input. This event only works on iOS, as there is no equivalent event to map to on Android

• paused — The application is not currently visible to the user, not responding to user input, and running in the background. This is equivalent to onPause() in Android

• resumed — The application is visible and responding to user input. This is equivalent to onPostResume() in Android

• suspending — The application is suspended momentarily. This is equivalent to onStop in Android; it is not triggered on iOS as there is no equivalent event to map to on iOS

flutter: AppLifecycleState.inactive
flutter: AppLifecycleState.paused
flutter: AppLifecycleState.inactive
flutter: AppLifecycleState.resumed

如果我們想監聽App級別的生命週期需要使用WidgetsBinding來監聽WidgetsBindingObserver.

Example:

class extends StatefulWidget {

  LifeCycle({Key key}): super(key: key);

  LifeCycleState createState() => new LifeCycleState();
}

class LifeCycleState extends State<LifeCycle> with WidgetsBindingObserver {

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

  @override
  Widget build(BuildContext context){
    return new MaterialApp(
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text(''),
        ),
        body: new Center(
          child: new Text(''),
        ),
      ),
    );
  }

 @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    switch (state) {
      case AppLifecycleState.inactive:
        print('AppLifecycleState.inactive');
        break;
      case AppLifecycleState.paused:
        print('AppLifecycleState.paused');
        break;
      case AppLifecycleState.resumed:
        print('AppLifecycleState.resumed');
        break;
      case AppLifecycleState.suspending:
        print('AppLifecycleState.suspending');
        break;
    }

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