Change app language programmatically in Android

Question

Is it possible to change the language of an app programmatically while still using Android resources?

If not, is it possible to request a resource in an specific lan

Answer 1

According to this article. You will need to download LocaleHelper.java referenced in that article.

1. Create MyApplication class that will extends Application
2. Override attachBaseContext() to update language.

3. Register this class in manifest.

   public class MyApplication extends Application {
      @Override
      protected void attachBaseContext(Context base) {
       super.attachBaseContext(LocaleHelper.onAttach(base, "en"));
      }
   }
   
   
   

4. Create BaseActivity and override onAttach() to update language. Needed for Android 6+

   public class BaseActivity extends Activity {
     @Override
     protected void attachBaseContext(Context base) {
       super.attachBaseContext(LocaleHelper.onAttach(base));
     }
   }
   

5. Make all activities on your app extends from BaseActivity.

   public 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);
   
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
           return updateResources(context, language);
       }
   
       return updateResourcesLegacy(context, language);
   }
   
   private 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);
       configuration.setLayoutDirection(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;
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
           configuration.setLayoutDirection(locale);
       }
   
       resources.updateConfiguration(configuration, resources.getDisplayMetrics());
   
       return context;
   }
   }