Flutter flatter_localizations错误在Null值上使用了Null判断运算符

我想让我的应用程序与导航抽屉. 当打开抽屉时，我得到了以下异常，该异常是由FIFTH_LOCALATION引起的.

微件库=======================================================捕获到异常 在生成NavigationDrawer时引发以下_CastError(脏，依赖项:[_LocalizationsScope-[GlobalKey#9fbb0]]): 在空值上使用的空判断运算符

import 'package:flutter/material.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const MaterialApp(
    localizationsDelegates: [
      AppLocalizations.delegate,
      GlobalMaterialLocalizations.delegate,
      GlobalWidgetsLocalizations.delegate,
      GlobalCupertinoLocalizations.delegate,
    ],
    supportedLocales: [
      Locale('en'),
      Locale('ja'),
    ],
    home: MyPage(),
  ));
}

/// A simple app that loads an adaptive banner ad.
class MyPage extends StatefulWidget {
  const MyPage({super.key});

  @override
  MyPageState createState() => MyPageState();
}

class NavigationDrawer extends StatelessWidget {
  const NavigationDrawer({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) => Drawer(
    child: SingleChildScrollView(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          buildMenuItems(context),
        ],
      ),
    ),
  );

  Widget buildMenuItems(BuildContext context) => Container(
    padding: const EdgeInsets.all(24),
    child: Wrap(
      runSpacing: 16,
      children: [
        ListTile(
          leading: const Icon(Icons.person),
          title: Text(AppLocalizations.of(context).person),
          onTap: (){},
        ),
      ],
    ),
  );
}

class MyPageState extends State<MyPage> {
  final _key = GlobalKey<ScaffoldState>();

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: AppLocalizations.of(context).appname,
      theme: ThemeData.light(),
      darkTheme: ThemeData.dark(),
      themeMode: ThemeMode.system,
      home: Scaffold(
        key: _key,
        appBar: AppBar(
          title: Text(AppLocalizations.of(context).appname),
        ),
        drawer: SafeArea(
          bottom: false,
          child: const NavigationDrawer(),
        ),
        body: Stack(
        ),),
    );
  }
}

AppLocalizations.of(上下文).appname运行良好. 但是AppLocalizations.of(Context).Person不起作用. 所以我猜NavigationDrawer中的上下文没有区域设置信息.