在Flutter中将本地化更改为阿拉伯语时，小部件方向不会更改为RTL

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

dev_dependencies:
  flutter_test:
    sdk: flutter
  intl: ^0.17.0

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

void main() {
  initializeDateFormatting().then((_) => runApp(MyApp()));
}

class AppLocalizations {
  static Future<AppLocalizations> load(Locale locale) {
    final String name =
        locale.countryCode.isEmpty ? locale.languageCode : locale.toString();
    final String localeName = Intl.canonicalizedLocale(name);

    return initializeMessages(localeName).then((_) {
      Intl.defaultLocale = localeName;
      return AppLocalizations();
    });
  }

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

  // TODO: 添加你需要的本地化文本
  String get appTitle {
    return Intl.message(
      'My App',
      name: 'appTitle',
    );
  }
}

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

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

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

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      localizationsDelegates: [
        const AppLocalizationsDelegate(),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en', ''),
        const Locale('ar', ''),
      ],
      title: 'My App',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    var localizations = AppLocalizations.of(context);

    return Scaffold(
      appBar: AppBar(
        title: Text(localizations.appTitle),
      ),
      body: Center(
        child: Text(
          localizations.appTitle,
          style: TextStyle(fontSize: 24),
        ),
      ),
    );
  }
}