Add a helper class with the following method:
public class LanguageHelper {
public static final void setAppLocale(String language, Activity activity) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
Resources resources = activity.getResources();
Configuration configuration = resources.getConfiguration();
configuration.setLocale(new Locale(language));
activity.getApplicationContext().createConfigurationContext(configuration);
} else {
Locale locale = new Locale(language);
Locale.setDefault(locale);
Configuration config = activity.getResources().getConfiguration();
config.locale = locale;
activity.getResources().updateConfiguration(config,
activity.getResources().getDisplayMetrics());
}
}
}
And call it in your startup activity, like MainActivity.java
:
public void onCreate(Bundle savedInstanceState) {
...
LanguageHelper.setAppLocale("fa", this);
...
}