Flutter localization

Flutter multi language without use package.

Android Screenshots Localizations

English language	Arabic language

steps

1. create file as assets

Directory assets

assets
└── lang
    ├── en.json
    └── ar.json

• set key and value
• en.json

{
    "title_Home": "Flutter Demo Home Page",
    "counter": "You have pushed the button this many times:",
    "tooltip_Increment": "Increment"
}

• ar.json

{
    "title_Home": "فلاتر ديو صفحة الرئيسية",
    "counter": "لقد ضغطت على الزر عدة مرات:",
    "tooltip_Increment": "زيادة"
}

2. Go to pubspec.yaml file.

• add flutter_localizations as dependencies.

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

• import file assets lang

 assets:
   - assets/lang/

3. create AppLocalizations and AppLocalizationsDelegate classes.

AppLocalizations

class AppLocalizations {
  late Locale locale;
  late Map<String, String> _valueText;
  AppLocalizations(this.locale);

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

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

  Future loadTranslateFile() async {
    String _langFile =
        await rootBundle.loadString('assets/lang/${locale.languageCode}.json');

    Map<String, dynamic> _json = jsonDecode(_langFile);
    _valueText = _json.map((key, value) => MapEntry(key, value.toString()));
  }

  String getTranslate(String key) {
    return _valueText[key]!;
  }
}

AppLocalizationsDelegate

class AppLocalizationsDelegate extends LocalizationsDelegate<AppLocalizations> {
  const AppLocalizationsDelegate();
  @override
  bool isSupported(Locale locale) {
    return ['en', 'ar'].contains(locale.languageCode);
  }

  @override
  Future<AppLocalizations> load(Locale locale) async {
    AppLocalizations appLocalizations = AppLocalizations(locale);
    await appLocalizations.loadTranslateFile();
    return appLocalizations;
  }

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

4. injection appLocalizations delegate in root widget.

MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      localizationsDelegates: const [
        AppLocalizations.delegate,
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: const [
        Locale('en', ''),
        Locale('ar', ''),
      ],
// check Locale supported
      localeResolutionCallback:
          (Locale? deviceLocale, Iterable<Locale> supportedLocales) =>
              deviceLocale != null &&
                      ['en', 'ar'].contains(deviceLocale.languageCode)
                  ? deviceLocale
                  : supportedLocales.first,
      home: const MyHomePage(),
    );

5. use AppLocalizations to get text.

AppLocalizations.of(context).getTranslate(keyJsonFile);
AppLocalizations.of(context).getTranslate('tooltip_Increment');

The end

Thank's to read ,hope help you.