Question

I have two applications installed on my emulator. The “manager” app sends a message to GCM. The other app called “scheduler” receives the message and displays a notification to the user.

When I have both applications running at the same time on the emulator, the manager app works fine. However, the scheduler app crashes after GCMIntentService processes onMessage(); This only happens on the first message. All remaining messages are processed without the application crashing.

No errors are printed out in the logcat.

Questions

1. Is there exception handling for GCMIntentService?
2. If the app is not visible and GCMIntentService calls a function to open an Activity. Can this crash the program?
3. If I have two apps running on the emulator at the same time could it be a problem with the emulator?

Here is the GCMIntentSerive code:

/**
 * {@link IntentService} responsible for handling GCM messages.
 */
public class GCMIntentService extends GCMBaseIntentService {
    @SuppressWarnings("hiding")
    private static final String TAG = "GCMIntentService";
    // Request code
    public static final int CUSTOM_REQUEST_CODE_ENTER_TEXT = 666;

    public GCMIntentService() {
        super(SENDER_ID);
    }

    @Override
    protected void onRegistered(Context context, String registrationId) {
        Log.i(TAG, "Device registered: " + "regId = " + registrationId);
      //  displayMessage(context, getString(R.string.gcm_registered));
        ServerUtilities.register(context, registrationId);

        displayError(context, "Device registered for Notifications from Anime Convention");
        System.out.println("Device registered: " + "regId = " + registrationId);
    }

    @Override
    protected void onUnregistered(Context context, String registrationId) {
        Log.i(TAG, "Device unregistered");
       // displayMessage(context, getString(R.string.gcm_unregistered));
        if (GCMRegistrar.isRegisteredOnServer(context)) {
            ServerUtilities.unregister(context, registrationId);
            System.out.println("Device Unregistered: " + "regId = " + registrationId);
        } else {
            // This callback results from the call to unregister made on
            // ServerUtilities when the registration to the server failed.
            Log.i(TAG, "Ignoring unregister callback");
        }
    }

    @Override
    protected void onMessage(Context context, Intent intent) {
        Log.i(TAG, "Received message");
        //String message = getString(R.string.gcm_message);

        System.out.println("onMessage: ");


        Bundle extras = intent.getExtras(); 

               String message =extras.getString("message");
               String event_id_from_server =extras.getString("server_id");
           //    displayMessage(context, message);
                generateNotification(context, message);
                saveMsg(message);    

                System.out.println("server id is "+ event_id_from_server);

                updateLocalDatabase(event_id_from_server);
        }


    @Override
    protected void onDeletedMessages(Context context, int total) {
        Log.i(TAG, "Received deleted messages notification");
        String message = getString(R.string.gcm_deleted, total);
       // displayMessage(context, message);
        // notifies user
        generateNotification(context, message);
    }

    @Override
    public void onError(Context context, String errorId) {
        Log.i(TAG, "Received error: " + errorId);

        if(errorId.equals("ACCOUNT_MISSING")){


        String error="Anime Convention Scheduler was unable to register your device for notifications. You need to add a GMAIL account to the phone inorder to use this service. Then use the Options Menu to register";

        displayError(context, error);
        displayMessage(context, error);
        }


     // save using saved preferences than display.
        if(errorId.equals("SERVICE_NOT_AVAILABLE")){

            String error="Google Cloud Messageing Service is not currently available";

            displayError(context, error);
        }


        // save using saved preferences than display.
        if(errorId.equals("AUTHENTICATION_FAILED")){
            String error="Google Cloud Messageing did not recognized your password. Please re-enter your password for your GMAIL account";
            displayError(context, error);
        }

        // save using saved preferences than display.
        if(errorId.equals("PHONE_REGISTRATION_ERROR") || errorId.equals("INVALID_PARAMETERS")){

            String error="Your phone does not support Google Cloud Messageing. You will not receive notifications from Anime Convention";
            displayError(context, error);
        }
    }

    @Override
    protected boolean onRecoverableError(Context context, String errorId) {
        // log message
        Log.i(TAG, "Received recoverable error: " + errorId);
     //   displayMessage(context, getString(R.string.gcm_recoverable_error,               errorId));

        return super.onRecoverableError(context, errorId);
    }

    /**
     * Issues a notification to inform the user that server has sent a message.
     */
    private static void generateNotification(Context context, String message) {
        int icon = R.drawable.icon;
        long when = System.currentTimeMillis();
        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        Notification notification = new Notification(icon, message, when);
        String title = context.getString(R.string.app_name);
        Intent notificationIntent = new Intent(context, TabBarExample.class);
        // set intent so it does not start a new activity
        notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP |Intent.FLAG_ACTIVITY_SINGLE_TOP);
        PendingIntent intent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
        notification.setLatestEventInfo(context, title, message, intent);
        notification.flags |= Notification.FLAG_AUTO_CANCEL;
        notificationManager.notify(0, notification);
    }

    private String handleMessage(Intent intent) {
        String id = intent.toString();
        String message = null;
        try {
            JSONObject json = new JSONObject(id);
             message = json.getString("message_id");
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return message;
    }

    public void saveMsg(String msg) {
        boolean worked = true;
        try {
            NotificationsDatabase entry = new NotificationsDatabase(GCMIntentService.this);
            entry.open();
            java.util.Date date= new java.util.Date();
             Timestamp x = new Timestamp(date.getTime());

            String timeStamp=x.toLocaleString();
            entry.createEntry(msg,timeStamp);

            entry.close();

            NoteAdapter note = null;
            note.notifyDataSetChanged();

            NewsRowAdapter nra  = null;
            nra.notifyDataSetChanged();

            AlertAdapter aa=null;
            aa.notifyDataSetChanged();
        } catch (Exception e) {
            worked = false;
            String error = e.toString();
            System.out.println(error);
        } finally {
            if (worked) {
            }
        }
    }
    @Override
    public void onDestroy() {
        GCMRegistrar.onDestroy(GCMIntentService.this.getApplicationContext());
        super.onDestroy();
    }

    public void updateLocalDatabase(String serverId){

        List<Alerts> listAlerts;

        int server_id=Integer.parseInt(serverId);

        DatabaseSqlite entry = new DatabaseSqlite (GCMIntentService.this);
        entry.open();
        listAlerts = entry.getData();       
        entry.close();

        int alerts=listAlerts.size();


        for (int i = 0; i < alerts; i++) {
            Alerts item = listAlerts.get(i);

        int remote_id =item.getRemoteServerId();
        String eventName=item.getEventName();
        int local_id=item.getRowId();

        if(server_id ==remote_id){

            //update database with new info

            // Calling startActivity() from outside of an Activity  context requires the FLAG_ACTIVITY_NEW_TASK flag
            Intent intent = new Intent(GCMIntentService.this, UpdateLocalDatabase.class);
            intent.putExtra("server_id", server_id);
            intent.putExtra("local_id", local_id);
            intent.putExtra("event_name", eventName);
            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            startActivity(intent);
            }
        }                   
    }
}

Answer 1

There were two problems with the code that created this issue.

1. I did not have a condition that checked if event_id_from_server was null or empty in the application.

2. When you send Message to GCM, they must not be null or “”. That crashes the service.
   So I needed to create this condition in the php for messages that did not have an id associated with them:

   if(!$id || $id==””){

       $fields = 
   array(
   'registration_ids' => $registrationIDs, 
   'data' => array("message" => $message), 
   'delay_while_idle'=> false,
   'collapse_key'=>'core_update'
   );
   
   
   
   }else{
   
   $fields = 
   array(
   'registration_ids' => $registrationIDs, 
   'data' => array("message" => $message,"server_id"=>$id), 
   'delay_while_idle'=> false,
   'collapse_key'=>'core_update'
   );
   
   }