Tutorial: How to use Google Play Services with Cocos2d-X for android

Consider viewing this post on my new blog:http://adrian-dawid.me/gulp/c++/2014/08/18/google-play-cocos2d-x-tutorial.html, I will post any updated information only there.

This is a short tutorial how to use Google Play Games Services with cocos2d-x. It describes how you add the library to your project. Google Play Games is a really handy tool for mobile game development, but there is almost no documentation how to use it with engines like Cocos2d-X, that are using the NDK and are designed to be cross platform compatible. I am using the JNI Bridge between C++ and Java here to use all the java functionality. There is also a c++ sdk, but it is also not easy to integrate into cocos2d-x too and has not the full feature-set of the java sdk.

1.Add the Google Play Games Services library and the BaseGameUtils to your project.

To use google play services you need to install the Google Play Services Library.

You can do that over the Android SDK Manager:

After you have installed the library you must copy it into the libs folder of your cocos2d-x android project. To do that copy the .jar, that is located in the your-sdk/extras/google/google_play_services/libproject/google-play-services_lib/libs/ folder into your project. For convenience you should also copy the file your-sdk/extras/google/google_play_services/libproject/google-play-services_lib/res/values/version.xml into you res/values folder, if you don’t do that you will have have to set the version number by yourself. You also need to copy the android-support-v4.jar file into your libs folder.

To use the Google Play Games Services in your app you also need the BaseGameUtils. The source is available on github:

https://github.com/playgameservices/android-basic-samples/tree/master/BasicSamples/libraries

Download the source as zip file or clone it onto your pc, then copy the .java files and the res folder into your project.

The BaseGameUtils are not made to be used with cocos2d-x or other native   engines, therefore we must change some things:

1.

Change the package of the BaseGameUtils files to org.cocos2dx.cpp 

IMPORTANT NOTICE:

You need to copy the files into the correct folder:

org/cocos2dx/cpp/*.java

2.

Change the base class of BaseGameActivity to Cocos2dxActvity. In order to do that you must add this line of code at the top of the file:

import org.cocos2dx.lib.Cocos2dxActivity;

This is necessary because the BaseGameActivity uses an std. Android Activity as it’s base class, but we want to see the results of the C++ based Cocos2dX renderer and therefore we must change the base class to Cocos2dxActivity. Cocos2dxActivity is the native activity that is used as the base class of the java AppActvity by default.

3.

Change the base class of your AppActivity class to BaseGameActivity and add an onCreate function.

Your class should look like this now:

         package org.cocos2dx.cpp;

         import org.cocos2dx.lib.Cocos2dxActivity;

          import your.app.id.*;

         import android.os.Bundle;

          public class AppActivity extends BaseGameActivity {

    

                    @Override

                      public void onSignInSucceeded(){

        

                    }

    

                      @Override

                       public void onSignInFailed(){

        

                      }

    

                       @Override

                       protected void onCreate(Bundle savedInstanceState) {

                              super.onCreate(savedInstanceState);

                      }

    

           }

4.

Add an import for your app id to all files. This is necessary because we need to access the android R class, and it is always in the std. package of our app, which is your app id  (you can find it in your android mainfest if you don’t know it anymore).

If you have done these steps you have added the Google Play Games Services Library and the BaseGameUtils to your project successfully. Now you should be able to compile your project, but it will most likely crash at startup, for the Google Play Games Services can not find an google play games app id.

2. Set your game up

To use Google Play Games Services  you need to set up your game in the cloud. You need to do that over the Google Play Console, please take a look at the documentation, if you want to find out how:

https://developers.google.com/games/services/console/enabling

Once you have created your game in the console, add these lines to your android manifest under the application tag:

                 <meta-data

                  android:name=”com.google.android.gms.games.APP_ID”

                  android:value=”@string/app_id” />

                  

                  <meta-data

                  android:name=”com.google.android.gms.appstate.APP_ID”

                  android:value=”@string/app_id”/>

                  

                 <meta-data android:name=”com.google.android.gms.version” android:value=”@integer/google_play_services_version” />

After you added this to the file you must add the @string/app_id resource to your project, in order to do that add a new file to the res/values folder and call it ids.xml. Use this template:

                  <resources>

                              <string name=”app_id”>your app id from the google play console</string>

                  </resources>

Now you can compile your app and you should see the Google Play Games Services Sign-In window at startup.

3 .Next Steps

Once you have set up your game you need to create java methods for the google play games functionality and c++ wrappers for them. Keep in mind, that it improves your performance if you transfer less data between C++ and Java.

I have created a C++ Wrapper and some Java files you can use, they are available at Github:

https://github.com/dwd31415/GameSharing