Registering the Android Client

Obtain a GCM Sender ID. See instructions in Google's documentation for "Registering for GCM."
In SAP Control Center configure push notification:
1. In the Android Push Notifications section of the corresponding Application Template use the GCM Sender ID value to update the Sender ID, and set Enabled to true.
2. Select Application > Properties > Push Configurations > Add to configure push settings in the application properties (setting the GCM server URL, and other parameters).
  - Use the API key from GCM to configure the API key.

Perform a one-time registration to enable push notifications for the application:

Create an application connection. For example, for Android devices:

POST http://{domain-host-port}/odata/applications/v1/{appid}/Connections
HTTP Header "Content-Type" = "application/atom+xml"
Body:
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices">
  <content type="application/xml">
    <m:properties>
      <d:DeviceModel>Samsung Galaxy S2</d:DeviceModel>
      <d:DeviceType>Android</d:DeviceType>
      <d:DeviceSubType>Smartphone</d:DeviceSubType>
      <d:DevicePhoneNumber>555-555-1212</d:DevicePhoneNumber>
      <d:DeviceIMSI>123456</d:DeviceIMSI>
    </m:properties>
  </content>
</entry>

Note: You can check the "AndroidGcmPushEnabled" value returned from the registration and only continue with the rest of the GCM/notification registration processing if it is "true".

The application registers with the GCM server, using the value from the "AndroidGcmSenderId" property, as well as the Android Application ID (which you build into the application).
A successful GCM registration results in a Registration ID back from Google.

Using the ApplicationConnectionId ({appcid}) returned from the SAP Mobile Platform registration call (in either the "X-SUP-APPCID" HTTP header or the "ApplicationConnectionId" property), the application should update the AndroidGcmRegistrationId property for the application connection for your application by using the GCM Registration ID returned by Google:

PUT http://{domain-host-port}/odata/applications/v1/{appid}/Connections/('{appcid}')
HTTP Headers "Content-Type" = "application/atom+xml" and "X-HTTP-METHOD" = "MERGE"
Body:
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices">
  <content type="application/xml">
    <m:properties>
      <d:AndroidGcmRegistrationId>{GCM registration ID}</d:AndroidGcmRegistrationId>
    </m:properties>
  </content>
</entry>

Native mobile listener should be implemented by the application to get the notification.