如何在flutter中打开系统特定的默认应用程序？

dependencies:
  url_launcher: ^6.0.0

import 'package:url_launcher/url_launcher.dart';

bool canLaunchUrl = await canLaunch(url);

if (canLaunchUrl) {
  await launch(url);
}

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

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Open Default App Example',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  final String url = 'https://www.example.com';

  Future<void> _openDefaultApp() async {
    bool canLaunchUrl = await canLaunch(url);
    if (canLaunchUrl) {
      await launch(url);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Open Default App Example'),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: _openDefaultApp,
          child: Text('Open Default App'),
        ),
      ),
    );
  }
}