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 language?

I would like to let the user change the language of the app from the app.

Answer 1

It work for me

Resources res = YourApplication.getInstance().getResources();
// Change locale settings in the app.
DisplayMetrics dm = res.getDisplayMetrics();
android.content.res.Configuration conf = res.getConfiguration();
conf.locale = new Locale("th");
res.updateConfiguration(conf, dm);

Answer 2

similar to the accepted answered but 2017 version and added restart (without restarting, sometimes the next Activity still renders English):

// Inside some activity...
private void changeDisplayLanguage(String langCode) {
// Step 1. Change the locale in the app's configuration
    Resources res = getResources();
    android.content.res.Configuration conf = res.getConfiguration();
    conf.setLocale(currentLocale);
    createConfigurationContext(conf);
// Step 2. IMPORTANT! you must restart the app to make sure it works 100%
    restart();
}
private void restart() {
    PackageManager packageManager = getPackageManager();
    Intent intent = packageManager.getLaunchIntentForPackage(getPackageName());
    ComponentName componentName = intent.getComponent();
    Intent mainIntent = IntentCompat.makeRestartActivityTask(componentName);
    mainIntent.putExtra("app_restarting", true);
    PrefUtils.putBoolean("app_restarting", true);
    startActivity(mainIntent);
    System.exit(0);
}

Answer 3

Here is some code that works for me:

public class  MainActivity extends AppCompatActivity {
public static String storeLang;

@Override
protected void onCreate(Bundle savedInstanceState) {

    SharedPreferences shp = PreferenceManager.getDefaultSharedPreferences(this);
    storeLang = shp.getString(getString(R.string.key_lang), "");

    // Create a new Locale object
    Locale locale = new Locale(storeLang);

    // Create a new configuration object
    Configuration config = new Configuration();
    // Set the locale of the new configuration
    config.locale = locale;
    // Update the configuration of the Accplication context
    getResources().updateConfiguration(
            config,
            getResources().getDisplayMetrics()
    );

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

Source: here

Answer 4

I was looking for a way to change the system language programmatically. While I fully understand that a normal application should never do that and instead either:

• the user should be pointed(through an intent) to the system settings to change it manually
• the application should handle its localization on its own just like described in the answer of Alex

there was a need to really change the language of the system programmtically.

This is undocumented API and thus should not be used for market/end-user applications!

Anyway heres the solution i found:

  Locale locale = new Locale(targetLocaleAsString);

  Class amnClass = Class.forName("android.app.ActivityManagerNative");
  Object amn = null;
  Configuration config = null;

  // amn = ActivityManagerNative.getDefault();
  Method methodGetDefault = amnClass.getMethod("getDefault");
  methodGetDefault.setAccessible(true);
  amn = methodGetDefault.invoke(amnClass);

  // config = amn.getConfiguration();
  Method methodGetConfiguration = amnClass.getMethod("getConfiguration");
  methodGetConfiguration.setAccessible(true);
  config = (Configuration) methodGetConfiguration.invoke(amn);

  // config.userSetLocale = true;
  Class configClass = config.getClass();
  Field f = configClass.getField("userSetLocale");
  f.setBoolean(config, true);

  // set the locale to the new value
  config.locale = locale;

  // amn.updateConfiguration(config);
  Method methodUpdateConfiguration = amnClass.getMethod("updateConfiguration", Configuration.class);
  methodUpdateConfiguration.setAccessible(true);
  methodUpdateConfiguration.invoke(amn, config);

Answer 5

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"));
      }
   }
   
   <application
        android:name="com.package.MyApplication"
        .../>
   

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;
   }
   }
   

Answer 6

I know it's late to answer but i found this article here . Which explains the whole process very well and provides you a well structured code.

Locale Helper class:

import android.annotation.TargetApi;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.preference.PreferenceManager;

import java.util.Locale;

/**
 * This class is used to change your application locale and persist this change for the next time
 * that your app is going to be used.
 * <p/>
 * You can also change the locale of your application on the fly by using the setLocale method.
 * <p/>
 * Created by gunhansancar on 07/10/15.
 */
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;
    }
}

You need to override attachBaseContext and call LocaleHelper.onAttach() to initialize the locale settings in your application.

import android.app.Application;
import android.content.Context;

import com.gunhansancar.changelanguageexample.helper.LocaleHelper;

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

All you have to do is to add

LocaleHelper.onCreate(this, "en");

wherever you want to change the locale.