flutter-localizations

home_page.dart

import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';
import 'package:your_app_package/services/localization/app_translations_delegate.dart';
import 'package:your_app_package/screens/home_page.dart';
import 'application.dart';

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  AppTranslationsDelegate _newLocaleDelegate;

  @override
  void initState() {
    super.initState();
    _newLocaleDelegate = AppTranslationsDelegate(newLocale: null);
    application.onLocaleChanged = onLocaleChange;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
      localizationsDelegates: [
        _newLocaleDelegate,
        const AppTranslationsDelegate(),
        //provides localised strings
        GlobalMaterialLocalizations.delegate,
        //provides RTL support
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: application.supportedLocales(),
    );
  }

  void onLocaleChange(Locale locale) {
    setState(() {
      _newLocaleDelegate = AppTranslationsDelegate(newLocale: locale);
    });
  }
}