Setting up and configuring GCM for your application

To setup Google Cloud Messaging on your application you will have to register with GCM and set up a Google API Project on your Google Developers Console (https://developers.google.com/mobile/add):

1. First pick Android App Platform

2. Specify your application name

   Example: Asynchronous Android

3. Supply your application package name

   Example: com.packpublishing.asynchronousandroid

4. Select Cloud Messaging Services and Enable Google Cloud Messaging

5. Generate the configuration files and download the JSON configuration file google-services.json to your computer.

6. Save your credentials (Server APIKey, SenderId) to authenticate with the GCM platform

Once you have registered your application with GCM, get the google-services.json configuration file and copy the file into the app/ or mobile/ directory of your Android Studio Project.

Next, add the Google Play Services SDK to your project level and app-level <PROJECT_DIRECTORY>/build.gradle file and rebuild...