Change app language at run time in Android

I am trying to change the language of my Android app with no success. I have:

/res/ . values/ . . string.xml . . values-es/ . . . strings.xml 

Both strings files contains the same but the content is translated according to the language code. The default language is english but I want to do some tests and use the spanish language.

I use the code written in this previous question: Change app language programmatically in Android

Here is my LoginActivity(launcher)'s onCreate method:

protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // setting default screen to login.xml setContentView(R.layout.login); Resources res = getBaseContext().getResources(); // Change locale settings in the app. DisplayMetrics dm = res.getDisplayMetrics(); android.content.res.Configuration conf = res.getConfiguration(); conf.locale = new Locale("es"); res.updateConfiguration(conf, dm); TextView registerScreen = (TextView) findViewById(R.id.link_to_register); // Listening to register new account link registerScreen.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // Switching to Register screen Intent i = new Intent(getApplicationContext(), RegisterActivity.class); startActivity(i); } }); Button mainMenu = (Button) findViewById(R.id.btnLogin); // Listening to register new account link mainMenu.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { // Switching to Register screen Intent i = new Intent(getApplicationContext(), MainMenuActivity.class); startActivity(i); } }); } 

My target is Android 4.4.

However, this is not working on my Nexus 4 - Android 4.4, it always uses English language.