GCM sendRegistrationIdToBackend is undefined

Question

I am trying to set up GCM but my project doesn't recognize certain methods. I followed the advice of many other links which was to import GCM and google play services but I am still getting no such luck. Thanks for looking.

Edit: I've cleaned a million times and rebuilt.

Answer 1

I'm not sure where you got the code of the demo app from, but there are several things wrong with it.

First of all, the method you are missing is not implemented in the Demo. It has an empty body :

/**
 * Sends the registration ID to your server over HTTP, so it can use GCM/HTTP or CCS to send
 * messages to your app. Not needed for this demo since the device sends upstream messages
 * to a server that echoes back the message using the 'from' address in the message.
 */
private void sendRegistrationIdToBackend() {
  // Your implementation here.
}

It's your responsibility to implement it, since its implementation depends on your server implementation.

Another error (you'd get an exception after you fix the compilation error) is calling gcm.register() from the main thread. You must call it in the background :

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    mDisplay = (TextView) findViewById(R.id.display);

    context = getApplicationContext();

    // Check device for Play Services APK. If check succeeds, proceed with GCM registration.
    if (checkPlayServices()) {
        gcm = GoogleCloudMessaging.getInstance(this);
        regid = getRegistrationId(context);

        if (regid.isEmpty()) {
            registerInBackground();
        }
    } else {
        Log.i(TAG, "No valid Google Play Services APK found.");
    }
}

/**
 * Registers the application with GCM servers asynchronously.
 * <p>
 * Stores the registration ID and the app versionCode in the application's
 * shared preferences.
 */
private void registerInBackground() {
    new AsyncTask<Void, Void, String>() {
        @Override
        protected String doInBackground(Void... params) {
            String msg = "";
            try {
                if (gcm == null) {
                    gcm = GoogleCloudMessaging.getInstance(context);
                }
                regid = gcm.register(SENDER_ID);
                msg = "Device registered, registration ID=" + regid;

                // You should send the registration ID to your server over HTTP, so it
                // can use GCM/HTTP or CCS to send messages to your app.
                sendRegistrationIdToBackend();

                // For this demo: we don't need to send it because the device will send
                // upstream messages to a server that echo back the message using the
                // 'from' address in the message.

                // Persist the regID - no need to register again.
                storeRegistrationId(context, regid);
            } catch (IOException ex) {
                msg = "Error :" + ex.getMessage();
                // If there is an error, don't just keep trying to register.
                // Require the user to click a button again, or perform
                // exponential back-off.
            }
            return msg;
        }

        @Override
        protected void onPostExecute(String msg) {
            mDisplay.append(msg + "\n");
        }
    }.execute(null, null, null);
}

All code samples are taken from the official GCM Demo app.