How to set language in Android

use the below class

public class LocaleHelper {

    private static final String SELECTED_LANGUAGE = "Locale.Helper.Selected.Language";

    public static void onCreate(Context context) {

        String lang = getPersistedData(context, Locale.getDefault().getLanguage());

        setLocale(context, lang);

    }

    public static void onCreate(Context context, String defaultLanguage) {

        String lang = getPersistedData(context, defaultLanguage);

        setLocale(context, lang);

    }

    public static String getLanguage(Context context) {

        return getPersistedData(context, Locale.getDefault().getLanguage());

    }

    public static void setLocale(Context context, String language) {

        persist(context, language);

        updateResources(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();

    }

    private static void updateResources(Context context, String language) {

        Locale locale = new Locale(language);

        Locale.setDefault(locale);

        Resources resources = context.getResources();

        Configuration configuration = resources.getConfiguration();

        configuration.locale = locale;

        resources.updateConfiguration(configuration, resources.getDisplayMetrics());

    }

}

How to use?

In Application

  public void onCreate() {

        super.onCreate();

        LocaleHelper.onCreate(this, "en");

 @Override

    public void onConfigurationChanged(Configuration newConfig) {

        super.onConfigurationChanged(newConfig);

        LocaleHelper.setLocale(this, LocaleHelper.getLanguage(this));

    }

Set the language

LocaleHelper.setLocale(this, "en");

How to change the language without restart the activity

LocaleHelper.setLocale(this, "zh");

set the text that you can see

e.g.

tvEn.setText(getContext().getString(R.string.en));

        tvTc.setText(getContext().getString(R.string.tc));

        tvChangePsw.setText(getContext().getString(R.string.change_psw));

        tvChangeLang.setText(getContext().getString(R.string.change_lang));

        tvPushNote.setText(getContext().getString(R.string.push_notic));

        tvPromotion.setText(getContext().getString(R.string.promotion));

        tvHealthTips.setText(getContext().getString(R.string.health_tips));

        tvLogout.setText(getContext().getString(R.string.logout));