How to change app language using switcher

Question

I have an Android app that contains two languages, I want to add switcher When pressed, the application is in English, When pressed, the application becomes Arabic

Answer 1

Call the below function to update the language.

private void updateLanguage(String languageCode)  //languageCode ex. 'en' for english 
{
    Context context = LocaleHelper.setLocale(MainActivity.this, languageCode);
    Log.v("langcode", languageCode);
    Resources resources = context.getResources();
}

Create a class named LocaleHelper to do the things.

class LocaleHelper {

private static final String SELECTED_LANGUAGE = "Locale.Helper.Selected.Language";

public static Context onAttach(Context context) {
    String lang = getPersistedData(context, Locale.getDefault().getLanguage());
    return setLocale(context, lang);
}

public static Context onAttach(Context context, String defaultLanguage) {
    String lang = getPersistedData(context, defaultLanguage);
    return setLocale(context, lang);
}

public static String getLanguage(Context context) {
    return getPersistedData(context, Locale.getDefault().getLanguage());
}

public static Context setLocale(Context context, String language) {
    persist(context, language);

    Log.v("abcdef", Locale.getDefault().getLanguage());

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        Log.v("Updatinglocale","Nougat");
        return updateResources(context, language);
    }

    return updateResourcesLegacy(context, language);
}

public static String getPersistedData(Context context, String defaultLanguage) {
    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
    return preferences.getString(SELECTED_LANGUAGE, defaultLanguage);
}

private static void persist(Context context, String language) {
    SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
    SharedPreferences.Editor editor = preferences.edit();

    editor.putString(SELECTED_LANGUAGE, language);
    editor.apply();
}

@TargetApi(Build.VERSION_CODES.N)
private static Context updateResources(Context context, String language) {
    Locale locale = new Locale(language);
    Locale.setDefault(locale);

    Configuration configuration = context.getResources().getConfiguration();
    configuration.setLocale(locale);

    return context.createConfigurationContext(configuration);
}

@SuppressWarnings("deprecation")
private static Context updateResourcesLegacy(Context context, String language) {
    Locale locale = new Locale(language);
    Locale.setDefault(locale);

    Resources resources = context.getResources();

    Configuration configuration = resources.getConfiguration();
    configuration.locale = locale;

    resources.updateConfiguration(configuration, resources.getDisplayMetrics());

    return context;
}

}