Question

I have read articles about GCM may refresh registration id with no regular cycle. I am trying to build an app using push notification but not so sure how to handle such refreshed registration ids.

My first strategy is requesting registration id everytime the app starts and send it to the app server. It looks working but sounds wrong somehow…

Is it ok to do like this?

Answer 1

Basically, you should do the following in your main activity:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.my_layout);

    GCMRegistrar.checkDevice(this);
    GCMRegistrar.checkManifest(this);

    final String regId = GCMRegistrar.getRegistrationId(this);

    if (regId.equals("")) {
        GCMRegistrar.register(this, GCMIntentService.GCM_SENDER_ID);
    } else {
        Log.v(TAG, "Already registered");
    }
}

Afterwards you should send the registration id to your app server, whenever the app receives an com.google.android.c2dm.intent.REGISTRATION intent with a registration_id extra. This could happen when Google periodically updates the app’s id.

You can achieve this by extending com.google.android.gcm.GCMBaseIntentService with your own implementation, e.g.:

public class GCMIntentService extends GCMBaseIntentService {

    // Also known as the "project id".
    public static final String GCM_SENDER_ID = "XXXXXXXXXXXXX";

    private static final String TAG = "GCMIntentService";

    public GCMIntentService() {
        super(GCM_SENDER_ID);
    }

    @Override
    protected void onRegistered(Context context, String regId) {
        // Send the regId to your server.
    }

    @Override
    protected void onUnregistered(Context context, String regId) {
        // Unregister the regId at your server.
    }

    @Override
    protected void onMessage(Context context, Intent msg) {
        // Handle the message.
    }

    @Override
    protected void onError(Context context, String errorId) {
        // Handle the error.
    }
}

For more details, I would (re)read the documentation for writing the client side code and the Advanced Section of the GCM documentation.

Hope that helps!