Flutter:如何让一个小部件在几秒钟后消失？

import 'package:flutter/material.dart';
import 'dart:async';

class DisappearingWidget extends StatefulWidget {
  @override
  _DisappearingWidgetState createState() => _DisappearingWidgetState();
}

class _DisappearingWidgetState extends State<DisappearingWidget> {
  bool _isVisible = true;

  @override
  void initState() {
    super.initState();
    // 在3秒后将小部件设为不可见
    Timer(Duration(seconds: 3), () {
      setState(() {
        _isVisible = false;
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Visibility(
      visible: _isVisible,
      child: Container(
        // 小部件的内容
        child: Text('这是一个会消失的小部件'),
      ),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Flutter小部件消失示例'),
        ),
        body: Center(
          child: DisappearingWidget(),
        ),
      ),
    );
  }
}