if (checkPlayServices()) {
        Log.i("udazzT","check servicies");
        // Start IntentService to register this application with GCM.
        Intent intent2 = new Intent(this,RegistrationIntentService.class);
        startService(intent2);
    }

但我在RegistrationIntentService中看不到任何日志：

public class RegistrationIntentService extends IntentService {

    private static final String TAG = "RegIntentService";
    private static final String[] TOPICS = {"global"};

    public RegistrationIntentService() {
        super(TAG);
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.i("udazzT","setting token");
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);

        try {
            // In the (unlikely) event that multiple refresh operations occur simultaneously,// ensure that they are processed sequentially.
            synchronized (TAG) {
                // [START register_for_gcm]
                // Initially this call goes out to the network to retrieve the token,subsequent calls
                // are local.
                // [START get_token]
                Log.i("udazzT","setting token 2");
                InstanceID instanceID = InstanceID.getInstance(this);
                String token = instanceID.getToken(getString(R.string.gcm_defaultSenderId),GoogleCloudMessaging.INSTANCE_ID_SCOPE,null);
                // [END get_token]
                Log.i(TAG,"GCM Registration Token: " + token);

                // TODO: Implement this method to send any registration to your app's servers.
                sendRegistrationToServer(token);

                // Subscribe to topic channels
                subscribeTopics(token);

                // You should store a boolean that indicates whether the generated token has been
                // sent to your server. If the boolean is false,send the token to your server,// otherwise your server should have already received the token.
                sharedPreferences.edit().putBoolean(QuickstartPreferences.SENT_TOKEN_TO_SERVER,true).apply();
                // [END register_for_gcm]
            }
        } catch (Exception e) {
            Log.d(TAG,"Failed to complete token refresh",e);
            // If an exception happens while fetching the new token or updating our registration data
            // on a third-party server,this ensures that we'll attempt the update at a later time.
            sharedPreferences.edit().putBoolean(QuickstartPreferences.SENT_TOKEN_TO_SERVER,false).apply();
        }
        // Notify UI that registration has completed,so the progress indicator can be hidden.
        Intent registrationComplete = new Intent(QuickstartPreferences.REGISTRATION_COMPLETE);
        LocalBroadcastManager.getInstance(this).sendBroadcast(registrationComplete);
    }

    /**
     * Persist registration to third-party servers.
     *
     * Modify this method to associate the user's GCM registration token with any server-side account
     * maintained by your application.
     *
     * @param token The new token.
     */
    private void sendRegistrationToServer(String token) {
        // Add custom implementation,as needed.
    }

    /**
     * Subscribe to any GCM topics of interest,as defined by the TOPICS constant.
     *
     * @param token GCM token
     * @throws IOException if unable to reach the GCM PubSub service
     */
    // [START subscribe_topics]
    private void subscribeTopics(String token) throws IOException {
        for (String topic : TOPICS) {
            GcmPubSub pubSub = GcmPubSub.getInstance(this);
            pubSub.subscribe(token,"/topics/" + topic,null);
        }
    }
    // [END subscribe_topics]

}