颤动：恢复小部件更新小部件？-Java 学习之路

在Flutter中，有没有办法在用户离开应用程序并更新回来时更新小部件？我的应用程序是基于时间的，尽快更新时间会很有帮助 .

2 回答

您可以收听生命周期事件

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((){}))
    );
  }
  ...
}

回复于 2024-04-28T15:54:01+08:00

使用系统 Channels ：

import 'package:flutter/services.dart';

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

回复于 2024-04-28T15:54:01+08:00

颤动：恢复小部件更新小部件？

2 回答

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