无法在flutter应用程序中查看列表中的详细信息

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'List Details Example',
      home: MyHomePage(),
      routes: {
        DetailPage.routeName: (context) => DetailPage(),
      },
    );
  }
}

class MyHomePage extends StatelessWidget {
  final List<String> items = ['Item 1', 'Item 2', 'Item 3'];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('List Example'),
      ),
      body: ListView.builder(
        itemCount: items.length,
        itemBuilder: (context, index) {
          return ListTile(
            title: Text(items[index]),
            onTap: () {
              Navigator.pushNamed(
                context,
                DetailPage.routeName,
                arguments: items[index],
              );
            },
          );
        },
      ),
    );
  }
}

class DetailPage extends StatelessWidget {
  static const routeName = '/detail';

  @override
  Widget build(BuildContext context) {
    final String item = ModalRoute.of(context)?.settings.arguments as String;

    return Scaffold(
      appBar: AppBar(
        title: Text('Detail Page'),
      ),
      body: Center(
        child: Text('Details for $item'),
      ),
    );
  }
}