<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"/>

 /**

  * @file gpg/android_initialization.h

  *

  * @brief Android specific initialization functions.

  */

 #ifndef GPG_ANDROID_INITIALIZATION_H_

 #define GPG_ANDROID_INITIALIZATION_H_

 #ifndef __cplusplus

 #error Header file supports C++ only

 #endif  // __cplusplus

 #include <android/native_activity.h>

 #include <jni.h>

 #include "gpg/common.h"

 // Forward declaration of android_app from android_native_app_glue.h.

 struct android_app;

 namespace gpg {

 /**

  * AndroidInitialization includes three initialization functions, exactly one of

  * which must be called. In the case of a standard Java Activity, JNI_OnLoad

  * should be used. In the case of a NativeActivity where JNI_OnLoad will not be

  * called, either android_main or ANativeActivity_onCreate should be used.

  * android_main is used when building a NativeActivity using

  * android_native_app_glue.h. ANativeActivity_onCreate is used when building a

  * NativeActivity using just native_activity.h. android_native_app_glue.h and

  * native_activity.h are default Android headers.

  *

  * The appropriate initialization function must be called exactly once before

  * any AndroidPlatformConfiguration instance methods are called, and it must be

  * called before a GameServices object is instantiated. It is permitted to

  * instantiate a AndroidPlatformConfiguration before one of the intialization

  * calls (for example, if the configuration object has global scope), as long as

  * no methods are called before the initialization call. These methods need be

  * called only once in the lifetime of the calling program, not once per

  * GameServices object created.

  */

 struct GPG_EXPORT AndroidInitialization {

   /**

    * When using Play Game Services with a standard Java Activity, JNI_OnLoad

    * should be called when the dynamic library's JNI_OnLoad is called.

    */

   static void JNI_OnLoad(JavaVM *jvm);

   /**

    * When using Play Game Services with a NativeActivity which is based on

    * android_native_app_glue.h, android_main should be called during your

    * activity's android_main, before any other Play Game Services calls.

    */

   static void android_main(struct android_app *app);

   /**

    * When using Play Game Services with a NativeActivity which is based on only

    * native_activity.h, ANativeActivity_onCreate should be called during your

    * activity's ANativeActivity_onCreate, before any other Play Game Services

    * calls.

    */

   static void ANativeActivity_onCreate(ANativeActivity *native_activity,

                                        void *savedState,

                                        size_t savedStateSize);

 };

 }  // namespace gpg

 #endif  // GPG_ANDROID_INITIALIZATION_H_

 #ifndef __cplusplus

 #error Header file supports C++ only

 #endif  // __cplusplus

 #include "gpg/common.h"

 namespace gpg {

 /**

  * Functions which enable pre- Android 4.0 support.

  *

  * <h1>Android Lifecycle Callbacks</h1>

  *

  * For apps which target Android 2.3 or 3.x devices (API Version prior to 14),

  * Play Game Services has no way to automatically receive Activity lifecycle

  * callbacks. In these cases, Play Game Services relies on the owning Activity

  * to notify it of lifecycle events. Any Activity which owns a GameServices

  * object should call the AndroidSupport::* functions from within their own

  * lifecycle callback functions. The arguments in these functions match those

  * provided by Android, so no additional processing is necessary.

  *

  * For apps which target android 4.0+ (API Version greater than or equal to 14),

  * most of these function calls are unnecessary. For such apps only the

  * OnActivityResult function must be called.

 ...