[英]Check if Stateless widget is disposed in flutter
当我的无状态小部件构建时,我使用以下代码按顺序播放一些声音:
await _audioPlayer.play(contentPath1, isLocal: true);
await Future.delayed(Duration(seconds: 4));
await _audioPlayer.play(contentPath2, isLocal: true);
await Future.delayed(Duration(seconds: 4));
await _audioPlayer.play(contentPath3, isLocal: true);
当用户在完成播放声音之前关闭当前小部件时,即使在使用以下代码关闭当前路由后声音仍然有效:
Navigator.pop(context);
我的解决方法是使用布尔变量来指示关闭操作是否已完成。
播放声音代码:
await _audioPlayer.play(contentPath1, isLocal: true);
if (closed) return;
await Future.delayed(Duration(seconds: 4));
if (closed) return;
await _audioPlayer.play(contentPath2, isLocal: true);
if (closed) return;
await Future.delayed(Duration(seconds: 4));
if (closed) return;
await _audioPlayer.play(contentPath3, isLocal: true);
关闭当前小部件:
closed = true;
_audioPlayer.stop();
如果我的小部件关闭,是否有更好的方法来停止异步方法?
如果您将小部件更改为 StatefulWidget,那么您可以拥有如下功能:
void _playSounds() {
await _audioPlayer.play(contentPath1, isLocal: true);
await Future.delayed(Duration(seconds: 4));
if (!mounted) return;
await _audioPlayer.play(contentPath2, isLocal: true);
await Future.delayed(Duration(seconds: 4));
if (!mounted) return;
await _audioPlayer.play(contentPath3, isLocal: true);
}
然后在 dispose 方法中处理播放器:
@override
void dispose() {
_audioPlayer?.dispose();
super.dispose();
}
mounted
getter 目前已合并到 master 频道中,但在稳定频道中仍不可用。
https://github.com/flutter/flutter/pull/111619
同时,我们有 2 个选项
mounted
的 getter。import 'package:flutter/material.dart';
class PrimitiveWrapper<T> {
T value;
PrimitiveWrapper(this.value);
}
class MountedWrapper extends StatefulWidget {
final Widget Function(BuildContext context, PrimitiveWrapper<bool> mounted) builder;
const MountedWrapper({
required this.builder,
super.key,
});
@override
State<MountedWrapper> createState() => _MountedWrapperState();
}
class _MountedWrapperState extends State<MountedWrapper> {
@override
Widget build(BuildContext context) {
return widget.builder.call(context, PrimitiveWrapper(mounted));
}
}
class SubmitBtn extends StatelessWidget {
...
Future<void> onSubmit(WidgetRef ref, BuildContext context, PrimitiveWrapper<bool> mounted) async {
...
await topicRepo.add(topic);
if (!mounted.value) {
return;
}
ScaffoldMessenger.of(context).showSnackBar(
const SnackBar(
content: Text('Created topic'),
),
);
}
@override
Widget build(BuildContext context) {
return MountedWrapper(
builder: (context, mounted) {
return Consumer(
builder: (context, ref, child) {
return ElevatedButton(
onPressed: () {
onSubmit(ref, context, mounted);
},
child: const Text('Create'),
);
},
);
},
);
}
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.