Google Play Games

Google Play Games is a games service primarily used on Android devices. It is a must-have for any Android-capable game.

Overview

Google Play Games belongs to the Google Play services, so you have to get a Google Developer Account and upload your signed APK to the Play Store in order to set it up. It does only work with a correctly signed app then.

Google Play Games supports the following features:

• Achievements
• Leaderboards
• Events
• Cloud save
• Real time and turn based multiplayer

Configure your Play Games project

Configure the project like expained in step 2 of Google's Getting started tutorial.

Note that you should link two applications in step 2.3: "My game" with your signing certificate, and "My game (debug)" with your debug certificate. Otherwise, you won't be able to test GPGS in your debug application.

Usage in your libGDX project

Add the dependency to your Android project:

compile "de.golfgl.gdxgamesvcs:gdx-gamesvcs-android-gpgs:$gamsvcsVersion"

Note that this dependency declares dependency to play services libraries. You can override the version with Gradle project properties, if needed.

Add the following lines to your AndroidManifest.xml and insert the following lines:

<meta-data android:name="com.google.android.gms.games.APP_ID"
    android:value="@string/app_id" />
<meta-data android:name="com.google.android.gms.version"
   android:value="@integer/google_play_services_version"/>

Of course then you need to add your App ID from the Developer Console in your res/value/strings.xml:

<string name="app_id">yourAppIdHere</string>

Change your AndroidLauncher to use the GpgsClient and initialize it:

    GdxGame game = new GdxGameSvcsApp();
    game.gsClient = new GpgsClient().initialize(this, false);
    initialize(game, config);

Don't forget to inform the gpgsClient about activity callbacks. Add the following to your AndroidLauncher:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    gpgsClient.onGpgsActivityResult(requestCode, resultCode, data);
}

Set up mapping when submitting events, scores or unlocking achievements

Unlike implementing API clients for Gamejolt or Newgrounds, GpgsClient does not need a specific setup for submitting events, scores and achievements to the service: You can just call the methods with the the Play Games IDs:

gpgsClient.unlockAchievement("CgkIu46Sr-8fEAIQAw");

However, I would not recommend to do so. Your game should call the interface method with a game service independant string constant for each event, leaderboard and achievement. Of course, your own constant will not work with the Play Games service. You can override the methods in your Android project to perform a mapping to the Play Games IDs:

    this.gpgsClient = new GpgsClient() {
        @Override
        public void showLeaderboards(String leaderBoardId) throws GameServiceException {
            super.showLeaderboards(GpgsMappers.mapToGpgsLeaderboard(leaderBoardId));
        }

        @Override
        public boolean submitToLeaderboard(String leaderboardId, long score, String tag) {
            return super.submitToLeaderboard(GpgsMappers.mapToGpgsLeaderboard(leaderboardId), score, tag);
        }
    }.initialize(this, false);

See sample app's Gpgs branch for a full example.

Cloud save

gdx-gamesvcs-gpgs implementation supports the usage of Google Play Games' powerful cloud save and sync feature. Just call loadGameState() and saveGameState(). Please note that you have to enable this feature both in Google's Developer Console and when calling the initialize method of GpgsClient.