Question 127579 in Android Studio Question posted in
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Android Studio – Flutter – How to persist selected language?

I folowed this video to implement localization in my app :- https://youtu.be/Zw4KoorVxgg

Everything works fine but when the app is relaunched the language gets set to default. How can I persiste the data.

[Note:- I am already using shared preference to persist some other data in my app, but I have no clue about persisting selected Locale]

This class below is called to set the locale:

class LocaleProvider extends ChangeNotifier {
  Locale? _locale;

  Locale? get locale => _locale;

  void setLocale(Locale locale) {
    if (!L10n.all.contains(locale)) return;
    _locale = locale;
    notifyListeners();
  }

  void clearLocale() {
    _locale = null;
    notifyListeners();
  }
}

And this is the screen where I set the language:

  class SelectLanguage extends StatefulWidget {
  const SelectLanguage({Key? key}) : super(key: key);

  @override
  _SelectLanguageState createState() => _SelectLanguageState();
}

class _SelectLanguageState extends State<SelectLanguage> {
  void setLocale(String selectedLocale) {
    final provider = Provider.of<LocaleProvider>(context, listen: false);
    provider.setLocale(
      Locale(selectedLocale),
    );
  }

  @override
  Widget build(BuildContext context) {
    return SafeArea(
      child: Scaffold(
        backgroundColor: Colors.black,
        body: Padding(
          padding:
          EdgeInsets.all(MediaQuery.of(context).size.width / 41.1),
          child: GridView(
            gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 2,
              childAspectRatio: 2.75,
              crossAxisSpacing: MediaQuery.of(context).size.width / 41.1,
              mainAxisSpacing: MediaQuery.of(context).size.width / 41.1,
            ),
            children: [
              LanguageTile(
                tileTitle: 'English',
                titleOnTap: () => setLocale('en'),
              ),
              LanguageTile(
                tileTitle: 'हिन्दी',
                titleOnTap: () => setLocale('hi'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}
Tags:

2

Answers


  1. 0

    using shared preference

    static Future<Locale> setLocale(String langCode) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setString(languageCode, langCode);
return locale(langCode);
}

static Locale locale(String languageCode) {
Locale _temp;
if (languageCode == 'hi') {
  _temp = Locale('hi');
}

else {
  _temp = Locale('en');
}
return _temp;
}

static Future<Locale> getLocale() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
String code = prefs.getString(languageCode);

print('language code:$code');

return locale(code);
}
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  2. 0

    create a class

        import 'dart:ui';

import 'package:shared_preferences/shared_preferences.dart';

const String LAGUAGE_CODE = 'languageCode';

//languages code
const String ENGLISH = 'en';
const String FRENCH = 'fr';
const String ARABIC = 'ar';
const String KINYARWANDA = 'rw';
const String SWAHILLI ="sw";

Future<Locale> storeLocale(String languageCode) async {
  SharedPreferences _prefs = await SharedPreferences.getInstance();
  await _prefs.setString(LAGUAGE_CODE, languageCode);
  return _locale(languageCode);
}

Future<Locale> getLocale() async {
  SharedPreferences _prefs = await SharedPreferences.getInstance();
  String languageCode = _prefs.getString(LAGUAGE_CODE) ?? ENGLISH;
  return _locale(languageCode);
}

Locale _locale(String languageCode) {
  switch (languageCode) {
    case ENGLISH:
      return const Locale(ENGLISH, '');
    case FRENCH:
      return const Locale(FRENCH, "");
    case ARABIC:
      return const Locale(ARABIC, "");
    case KINYARWANDA:
      return const Locale(KINYARWANDA, "");
    case SWAHILLI:
      return const Locale(SWAHILLI, "");
    default:
      return const Locale(ENGLISH, '');
  }
}

    then in your provider class add

         Future<void> setLocale(Locale locale) async{
    if(!L10n.all.contains(locale)) return;
    _locale =locale;
    storeLocale(locale.languageCode);//add this important
    // storelocal(locale.languageCode);
    notifyListeners();

  }

    where or widget you are implementing it e.g dropdown

    Widget build(BuildContext context) {
    final provider = Provider.of<LocaleProvider>(context,);
    final locale = provider.locale ?? const Locale('en');
    return DropdownButtonHideUnderline(
        child: DropdownButton(
      value: locale,
      icon: const Icon(Icons.language,color:Colors.white,),
      items: L10n.all.map((locale) {
        final flag = L10n.getFlag(locale.languageCode);
        return DropdownMenuItem(
          value: locale,
          onTap: ()async {
            //await storeLocale(locale.languageCode);//may uncomment this
            final provider =
                Provider.of<LocaleProvider>(context,listen: false );
            provider.setLocale(locale);
          },

    and in the main.dart change to stateful and override

     @override
  void didChangeDependencies() {
    super.didChangeDependencies();
   getLocale().then(
        (locale) => Provider.of<LocaleProvider>(context,listen: false).setLocale(locale));
  }

    hope this helps

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