LanguageSwitcher.java

package com.corewillsoft.usetool.utils;

import android.app.Activity;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.os.Handler;

import com.corewillsoft.usetool.ui.fragments.LanguagesFragment;
import com.google.inject.Inject;

import java.util.Locale;

import roboguice.context.event.OnCreateEvent;
import roboguice.activity.event.OnRestartEvent;
import roboguice.event.EventManager;
import roboguice.event.Observes;

/**
 * Recreates hosting {@link android.app.Activity} if the app {@link java.util.Locale} has been changed
 */
public class LanguageSwitcher {

    @Inject
    private EventManager eventManager;
    @Inject
    private Resources resources;
    @Inject
    private Activity activity;
    @Inject
    private SharedPreferences preferences;

    private Locale locale = null;

    public void onActivityCreated(@Observes OnCreateEvent event) {
        int index = preferences.getInt(LanguagesFragment.KEY_SELECTED_LANGUAGE, 0);
        if (index > 0) {
            LanguagesFragment.SupportedLanguage language = LanguagesFragment.SupportedLanguage.values()[index];
            locale = language.locale;
        } else {
            locale = resources.getConfiguration().locale;
        }
    }

    @SuppressWarnings("unused")
    public void onActivityRestarted(@Observes OnRestartEvent event) {
        if (locale != null && !locale.getLanguage().equals(resources.getConfiguration().locale.getLanguage())) {
            // added to avoid recreation Runtime exception in Android internals
            new Handler(activity.getMainLooper()).postDelayed(new Runnable() {
                @Override
                public void run() {
                    activity.recreate();
                }
            }, 1);
        }
    }
}