I develop an android application with GCM Push Notification. I have started to use the sample of google. Push notifications work when the device is "on". When the device fall asleep, notifications don't appear but they show when I get android device out of sleep mode.
I saw that when I publish a content in Facebook or Snapchat, notification works perfectly in sleep mode so my question is : When I receive a push notification and the device is in sleep mode, how to show this notification ?