I am using GCM in my application and also using NotificationManager to Create a Notification whenever GCM message is received.Till now everything is working perfectly and GC
Here you just passed your Intent into pendingintent: see below
Intent notificationIntent = new Intent(context, Login.class);
PendingIntent contentIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
and set this contentintent into your Notification:
Notification noti = new NotificationCompat.Builder(context)
.setSmallIcon(icon_small)
.setTicker(message)
.setLargeIcon(largeIcon)
.setWhen(System.currentTimeMillis())
.setContentTitle(title)
.setContentText(message)
.setContentIntent(**contentIntent**)
.setAutoCancel(true).build();
This may help you.