Questions tagged [android-c2dm]

The service provides a simple, lightweight mechanism that servers can use to tell mobile applications to contact the server directly, to fetch updated application or user data. The GCM service handles all aspects of queueing of messages and delivery to the target application running on the target device.

Characteristics

• It allows third-party application servers to send lightweight messages to their Android applications. The messaging service is not designed for sending a lot of user content via the messages. Rather, it should be used to tell the application that there is new data on the server, so that the application can fetch it.
• GCM makes no guarantees about delivery or the order of messages. So, for example, while you might use this feature to tell an instant messaging application that the user has new messages, you probably would not use it to pass the actual messages.
• An application on an Android device doesn’t need to be running to receive messages. The system will wake up the application via Intent broadcast when the message arrives, as long as the application is set up with the proper broadcast receiver and permissions.
• It does not provide any built-in user interface or other handling for message data. GCM simply passes raw message data received straight to the application, which has full control of how to handle it. For example, the application might post a notification, display a custom user interface, or silently sync data.
• It requires devices running Android 2.2 or higher that also have the Market application installed. However, you are not limited to deploying your applications through Market.
• It uses an existing connection for Google services. This requires users to set up their Google account on their mobile devices.

Google provides official documentation for this.