在 Flutter 中,有没有一种方法可以在用户离开应用程序并立即返回时更新小部件?我的应用是基于时间的,尽快更新时间会很有帮助。
最佳答案
例如,您可以通过这样做来监听生命周期事件:
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
class LifecycleEventHandler extends WidgetsBindingObserver {
final AsyncCallback resumeCallBack;
final AsyncCallback suspendingCallBack;
LifecycleEventHandler({
this.resumeCallBack,
this.suspendingCallBack,
});
@override
Future<void> didChangeAppLifecycleState(AppLifecycleState state) async {
switch (state) {
case AppLifecycleState.resumed:
if (resumeCallBack != null) {
await resumeCallBack();
}
break;
case AppLifecycleState.inactive:
case AppLifecycleState.paused:
case AppLifecycleState.detached:
if (suspendingCallBack != null) {
await suspendingCallBack();
}
break;
}
}
}
class AppWidgetState extends State<AppWidget> {
void initState() {
super.initState();
WidgetsBinding.instance.addObserver(
LifecycleEventHandler(resumeCallBack: () async => setState(() {
// do something
}))
);
}
...
}
https://stackoverflow.com/questions/49869873/