LocaleHelper.java

package com.mobapphome.mahads.sample;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.preference.PreferenceManager;
import android.util.Log;

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 = "MAHAds.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) {
        Log.i(MainActivity.LOG_TAG_MAH_ADS_SAMPLE, "Language = " + 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());
    }
}


//    //This for tip
//    //This for refreshing strings when lacale has changed.
//    //Write this kind of method to activity or fragment
//    private void updateViews() {
//        // if you want you just call activity to restart itself to redraw all the widgets with the correct locale
//        // however, it will cause a bad look and feel for your users
//        //
//        // this.recreate();
//
//        //or you can just update the visible text on your current layout
//        Resources resources = getResources();
//
//        mTitleTextView.setText(resources.getString(R.string.title_text));
//        mDescTextView.setText(resources.getString(R.string.desc_text));
//        mAboutTextView.setText(resources.getString(R.string.about_text));
//    }