Configuring Google Cloud Messaging Service

Google Cloud Messaging (GCM) is a service that allows you to send data from the server to Android devices, and also to receive messages from devices on the same connection.

1. Open the Google Developers Console.
2. Click Create Project to create an API project.
3. Enter a project name and click Create .
   A page displays your project ID and project number.
4. Record the project number for later use as the GCM sender ID.
5. Enable the GCM service.
   1. In the sidebar on the left, select APIs & auth.
   2. In the displayed list of APIs, turn the Google Cloud Messaging for Android toggle to ON.
6. Obtain an API key.
   1. In the sidebar on the left, select APIs & auth > Credentials.
   2. Under Public API access, click Create new key.
   3. In the Create a new key dialog, click Android key.
   4. In the resulting configuration dialog, supply one SHA1 fingerprint and the package name for your app, separated by a semicolon. For example, 45:B5:E4:6F:36:AD:0A:98:94:B4:02:66:2B:12:17:F2:56:26:A0:E0;com.myexample.
      To get the value for the SHA1 fingerprint, follow the instructions in the  console help .
   5. Click Create.
   6. Record the API key for later use to perform authentication in your application server.