如何在Flutter中自动关闭对话框警告小工具？

import 'package:flutter/material.dart';

class DialogUtils {
  static void showAlertDialog(BuildContext context, String message) {
    showDialog(
      context: context,
      builder: (BuildContext context) {
        return AlertDialog(
          title: Text('警告'),
          content: Text(message),
          actions: <Widget>[
            FlatButton(
              child: Text('关闭'),
              onPressed: () {
                Navigator.pop(context); // 关闭对话框
              },
            ),
          ],
        );
      },
    );
  }
}

// 使用示例
void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('对话框示例'),
        ),
        body: Center(
          child: RaisedButton(
            child: Text('显示警告对话框'),
            onPressed: () {
              DialogUtils.showAlertDialog(context, '这是一个警告信息');
            },
          ),
        ),
      ),
    );
  }
}