Before you begin
This developer guide will show you how to compile and run a C++ game on Android that uses the Google Play Game services API. Before you begin, download and configure the following requirements:
- Android NDK, Revision 14 or higher.
- Android SDK v10 or higher and latest version of the Eclipse ADT.
- Device must be running Android 4.0 (API level 14) or higher.
- The latest version of the Google Play services SDK.
This developer guide uses the Android Native Development Kit (NDK). If you are unfamiliar with the NDK, refer to the NDK documentation and samples before continuing.
Step 1: Set up your environment
- Download the Android SDK and the Android NDK and extract them to your machine. In your
environment, set
SDK_ROOT
to the location of your Android SDK folder andNDK_ROOT
to the location of your Android NDK folder. - Download the C++ sample games. This
developer guide refers to the location of the samples on your machine as
SAMPLES_DIR
. - Download the Google Play Games services C++ SDK. Extract the
SDK onto your development machine. In your environment, set the variable
NDK_MODULE_PATH
to point to the directory above thegpg-cpp-sdk
directory. You should have the following directory structure:NDK_MODULE_PATH/ gpg-cpp-sdk/
- Open Eclipse. If you have not already done so, tell Eclipse where you installed the NDK by clicking Preferences > Android > NDK.
Import the Google Play services library project into your Eclipse workspace.
- In Eclipse, click File > Import > Android > Existing Android Code into Workspace.
- Select
SDK_ROOT/extras/google/google_play_services/libproject/google-play-services_lib
whereSDK_ROOT
is the location of your Android SDK. - Click Finish.
Import the minimalist sample project into your Eclipse workspace.
- In Eclipse, click File > Import > Android > Existing Android Code into Workspace.
- Select
SAMPLES_DIR/samples-android/minimalist
. - Click Finish.
Right click the MinimalistActivity project and click Properties. Under Android, scroll down to the Library section and make sure the google-play-services_lib project is correctly referenced. If not, remove the reference and add it again from your workspace.
Eclipse will automatically compile the Java and Android sources of your project; however, the
native code in the jni
folder needs to be compiled separately. To do this manually, navigate to
the jni
folder and run ndk-build
. Remember to do this after you make any changes inside
the jni
folder.
Your project should now compile, though it will not work yet. You must first configure your game in the Google Play Console.
Step 2: Set up the game in the Google Play Console
Create an entry for your game in the Google Play Console. This enables Games services for your application, and creates an OAuth 2.0 client ID, if you don't already have one.
- Create an entry for your game by following the steps described in Setting Up Google Play Games Services.
- In
AndroidManifest.xml
, change thepackage
attribute of the<manifest>
tag to the package name you chose when setting up the Google Play Console. You may have to fix some references throughout the project after making this change (particularly to the generatedR
class). - Open
res/values/ids.xml
and place your App ID there. Note that the App ID is not the same as the client ID; it is the number next to the name of your game in the Game Details page of the Google Play Console.
Step 3: Run the sample
In order to run the sample you will need a physical Android device or an emulator with Google Play services installed:
- Run
ndk-build
to compile the native code. - In Eclipse, click Run > Run As > Android Application and run the sample on your device.
- When the sample opens, tap anywhere on the scren. You should see a Google Play Games logo appear. If you have correctly configured your app, you will be prompted to sign in.
Optional: Building Automatically with Eclipse
The following steps show you how to configure Eclipse to automatically run ndk-build
when you
make changes to files in the jni
folder.
- Right-click the MinimalistActivity project and click Properties. In the Properties window, select the Builders pane.
- Click New to add a new Builder and select Program then click OK.
- In the Name field, enter 'NDK Builder'.
- Under Location click Browse File System and navigate to the
NDK_ROOT
directory and select thendk-build
command. - Under Working Directory click Browse Workspace and select the MinimalistActivity project folder.
- Click the Refresh tab. Make sure the Refresh resources upon completion box is checked.
- Select the Specific resources radio button and then click Specify Resources. In the
resulting dialog, select the
jni
folder under MinimalActivity. - Click Apply and then OK to finish creating your Builder.
Now every time you edit a file within the jni
folder, Eclipse will run ndk-build
and print the
output to the Eclipse Console.