This class is used to change your application locale and save this change for the next time.

LocalUtility.java

/**
 * Created by Alhazmy13 on 11/6/16.
 */
public class LocalUtility {

     private static final String SAVED_LANG = "LOCALE_SAVED_LANG";

    public static void onCreate(Context context) {
        String lang = getSavedData(context, Locale.getDefault().getLanguage());
        setLocale(context, lang);
    }

    public static void onCreate(Context context, String defaultLanguage) {
        String lang = getSavedData(context, defaultLanguage);
        setLocale(context, lang);
    }

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

    public static void setLocale(Context context, String language) {
        save(context, language);
        updateConfiguration(context, language);
    }

    private static String getSavedData(Context context, String defaultLanguage) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        return preferences.getString(SAVED_LANG, defaultLanguage);
    }

    private static void save(Context context, String language) {
        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
        SharedPreferences.Editor editor = preferences.edit();
        editor.putString(SAVED_LANG, language);
        editor.apply();
    }

    private static void updateConfiguration(Context context, String language) {
        Locale locale = new Locale(language);
        Locale.setDefault(locale);
        Resources resources = context.getResources();
        Configuration configuration = resources.getConfiguration();
        configuration.setLocale(locale);
        resources.updateConfiguration(configuration, resources.getDisplayMetrics());
    }
}