Open lib/main.dart and replace its full contents with the
following:

    
 import 'package:flutter/material.dart';
 import 'package:path/path.dart' as p;
 import 'package:url_launcher/url_launcher.dart';

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

 class MyApp extends StatelessWidget {
   const MyApp({super.key});

   @override
   Widget build(BuildContext context) {
     return const MaterialApp(
       home: DemoPage(),
     );
   }
 }

 class DemoPage extends StatelessWidget {
   const DemoPage({super.key});

   launchURL() {
     launchUrl(p.toUri('https://flutter.dev'));
   }