如何使用flutter本地化launcher中显示的应用名称？

{
  "@@locale": "en",
  "app_name": "My App"
}

{
  "@@locale": "zh",
  "app_name": "我的应用"
}

dependencies:
  flutter_localizations:
    sdk: flutter
  flutter_localized_locales:
    sdk: flutter

import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'l10n/l10n.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: [
        AppLocalizations.delegate,
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: AppLocalizations.supportedLocales,
      title: AppLocalizations.of(context).appName,
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(AppLocalizations.of(context).appName),
      ),
      body: Center(
        child: Text(AppLocalizations.of(context).appName),
      ),
    );
  }
}

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

class AppLocalizations {
  final Locale locale;

  AppLocalizations(this.locale);

  static AppLocalizations of(BuildContext context) {
    return Localizations.of<AppLocalizations>(context, AppLocalizations);
  }

  static const LocalizationsDelegate<AppLocalizations> delegate =
      _AppLocalizationsDelegate();

  static List<Locale> get supportedLocales {
    return const [
      Locale('en', ''),
      Locale('zh', ''),
    ];
  }

  String get appName {
    switch (locale.languageCode) {
      case 'zh':
        return '我的应用';
      default:
        return 'My App';
    }
  }
}

class _AppLocalizationsDelegate
    extends LocalizationsDelegate<AppLocalizations> {
  const _AppLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) {
    return ['en', 'zh'].contains(locale.languageCode);
  }

  @override
  Future<AppLocalizations> load(Locale locale) {
    return SynchronousFuture<AppLocalizations>(AppLocalizations(locale));
  }

  @override
  bool shouldReload(_AppLocalizationsDelegate old) {
    return false;
  }
}