Flutter Localization Gist

localizations.dart

import 'dart:async';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart' show SynchronousFuture;

class AppLocalizations {

  AppLocalizations(this.locale);

  final Locale locale;

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

  static Map<String, Map<String, String>> _localizedValues = {

    'en': {

      'appName': 'Localization Demo',

      'appNameShort': 'Localization',

      'title': 'FlutterDevs',

      'desc': 'FlutterDevs intent to deliver Flutter apps with '

          'high quality. We’ve adopted Design First attitude '

          'which helps us deliver applications of highest quality.',

    },

    'hi': {

      'appName': 'लोकलाइजेशन डेमो',

      'appNameShort': 'लोकलाइजेशन',

      'title': 'फ्लूटेरडेव्स',

      'desc': 'FlutterDevs उच्च गुणवत्ता वाले Flutter ऐप्स वितरित करने '

          'का इरादा रखता है। हमने डिजाइन फर्स्ट रवैया अपनाया है जो हमें '

          'उच्चतम गुणवत्ता के अनुप्रयोगों को वितरित करने में मदद करता है।',

    },

  };

  String get appName {
    return _localizedValues[locale.languageCode]['appName'];
  }

  String get appNameShort {
    return _localizedValues[locale.languageCode]['appNameShort'];
  }

  String get title {
    return _localizedValues[locale.languageCode]['title'];
  }

  String get desc {
    return _localizedValues[locale.languageCode]['desc'];
  }

}

class AppLocalizationsDelegate extends LocalizationsDelegate<AppLocalizations> {

  const AppLocalizationsDelegate();

  @override
  bool isSupported(Locale locale) => ['en', 'hi'].contains(locale.languageCode);

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

  @override
  bool shouldReload(AppLocalizationsDelegate old) => false;
}

main_1.dart

import 'package:flutter_localization_app/localization/localizations.dart';

main_2.dart

localizationsDelegates: [
 AppLocalizationsDelegate(),
 GlobalMaterialLocalizations.delegate,
 GlobalWidgetsLocalizations.delegate,
],
supportedLocales: [
 const Locale('en', ''), // English
 const Locale('hi', ''), // Hindi
],
locale: locale,

main_3.dart

_fetchLocale() async {
    var prefs = await SharedPreferences.getInstance();
    if (prefs.getString('languageCode') == null) {
      return null;
    }

    print('_fetchLocale():' +
        (prefs.getString('languageCode') +':' + prefs.getString('countryCode')));

return Locale(
        prefs.getString('languageCode'), prefs.getString('countryCode'));
  }

main_4.dart

static void setLocale(BuildContext context, Locale newLocale) async {
 _MyAppState state = context.ancestorStateOfType(TypeMatcher<_MyAppState>());
 state.setState(() {
   state.locale = newLocale;
 });
}

main_5.dart

void _updateLocale(String lang, String country) async {
                var prefs = await SharedPreferences.getInstance();
                prefs.setString('languageCode', lang);
                prefs.setString('countryCode', country);
                MyApp.setLocale(context, Locale(lang, country));
}

pubspec.yaml

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