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Flutter: mettre à jour les widgets sur Reprendre?

Dans Flutter, existe-t-il un moyen de mettre à jour les widgets lorsque l'utilisateur quitte l'application et y revient? Mon application est basée sur le temps, et il serait utile de mettre à jour l'heure dès que possible.

dartflutter
6
Joshua Van Deren

Vous pouvez écouter les événements du cycle de vie

class LifecycleEventHandler extends WidgetsBindingObserver {
  LifecycleEventHandler({this.resumeCallBack, this.suspendingCallBack});

  final FutureVoidCallback resumeCallBack;
  final FutureVoidCallback suspendingCallBack;

  @override
  Future<Null> didChangeAppLifecycleState(AppLifecycleState state) async {
    switch (state) {
      case AppLifecycleState.inactive:
      case AppLifecycleState.paused:
      case AppLifecycleState.suspending:
        await suspendingCallBack();
        break;
      case AppLifecycleState.resumed:
        await resumeCallBack();
        break;
    }
  }
}


class AppWidgetState extends State<AppWidget> {
  void initState() {
    super.initState();

    WidgetsBinding.instance.addObserver(
        new LifecycleEventHandler(resumeCallback(() => setState((){}))
    );
  }
  ...
}
7
Günter Zöchbauer

Utilisation du canal système:

import 'package:flutter/services.Dart';

SystemChannels.lifecycle.setMessageHandler((msg){
  debugPrint('SystemChannels> $msg');
  if(msg==AppLifecycleState.resumed.toString())setState((){});
});

`

3
UpaJah

Manière simple:

import 'package:flutter/services.Dart';

handleAppLifecycleState() {
    AppLifecycleState _lastLifecyleState;
    SystemChannels.lifecycle.setMessageHandler((msg) {

     print('SystemChannels> $msg');

        switch (msg) {
          case "AppLifecycleState.paused":
            _lastLifecyleState = AppLifecycleState.paused;
            break;
          case "AppLifecycleState.inactive":
            _lastLifecyleState = AppLifecycleState.inactive;
            break;
          case "AppLifecycleState.resumed":
            _lastLifecyleState = AppLifecycleState.resumed;
            break;
          case "AppLifecycleState.suspending":
            _lastLifecyleState = AppLifecycleState.suspending;
            break;
          default:
        }
    });
  }

ajoutez simplement handleAppLifecycleState() dans votre init()

OU

class AppLifecycleReactor extends StatefulWidget {
      const AppLifecycleReactor({ Key key }) : super(key: key);

      @override
      _AppLifecycleReactorState createState() => _AppLifecycleReactorState();
    }

    class _AppLifecycleReactorState extends State<AppLifecycleReactor> with WidgetsBindingObserver {
      @override
      void initState() {
        super.initState();
        WidgetsBinding.instance.addObserver(this);
      }

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

      AppLifecycleState _notification;

      @override
      void didChangeAppLifecycleState(AppLifecycleState state) {
        setState(() { _notification = state; });
      }

      @override
      Widget build(BuildContext context) {
        return Text('Last notification: $_notification');
      }
    }

Pour plus de détails, vous vous référez documentation

0
Rahul Mahadik