How to use shared preference to save user selected language with bloc approach

Question

I have a bloc cubit to change language from English to Arabic and when I click on change button the language change successfully , but when I'm closing the app and return again the default language is return to work .

this is my language cubit

class LocaleCubit extends Cubit<LocaleState> {
  LocaleCubit() : super(SelectedLocale(Locale('ar')));

  void toArabic() => emit(SelectedLocale(Locale('ar')));

  void toEnglish() => emit(SelectedLocale(Locale('en')));
} 

and this is the usage in main

supportedLocales: AppLocalizationsSetup.supportedLocales,
            localizationsDelegates:
                AppLocalizationsSetup.localizationsDelegates,
            localeResolutionCallback:
                AppLocalizationsSetup.localeResolutionCallback,
            locale: localeState.locale,

so can anyone know how to use shared preference to save the language value when user open the app again .

Answer 1

You can inject the sharedPreferences object into the Cubit.

class LocaleCubit extends Cubit<LocaleState> {
  final SharedPreferences _preferences;
LocaleCubit(this._preferences) : super(SelectedLocale(Locale(_preferences.getString('locale')??'ar')));
// Here we initialize the object to the last saved locale and default to 'ar' if there is none


// Method that saves and emits the new locale
  void _changeLocale(String locale) { 
_preferences.setString('locale',locale);
emit(SelectedLocale(Locale(locale)));
}
  void toEnglish() => _changeLocale'en');
  void toArabic() => _changeLocale('ar');
} 

Your Cubit has the same API as before , only that now the values are being saved on each state change, and the SharedPreferences must be passed to the constructor.