2. •Google Cloud Messaging for Android (GCM) is a
free service that helps developers send data from
servers to their Android applications on Android
devices.
•Message containing up to 4kb of payload data.
•The GCM service handles all aspects of queuing of
messages and delivery to the target Android
application running on the target device.
•It doesn’t necessary that your application in
running state 24X7.

3. 1. Application Server.
2. Google Account.
3. Android Phone/ emulator(Google API).

4. 1. Registration ID- An ID issued by the GCM servers to the Android
application that allows it to receive messages. Once the Android application has
the registration ID, it sends it to the 3rd-party application server, which uses it
to identify each device that has registered to receive messages for a given
Android application. In other words, a registration ID is tied to a particular
Android application running on a particular device.
2. Sender Auth Token- An API key that is saved on the 3rd-party
application server that gives the application server authorized access to Google
services. The API key is included in the header of POST requests that send
messages.
3. Sender ID- A project ID you acquire from the API console The sender ID
is used in the registration process to identify an Android application that is
permitted to send messages to the device.
4. Pay Load – your data.

5. 1.Client will send
activation request, via
our application
2.Client will receive
response with unique
Registration ID.
5. GCM server push the
data with GCM
technology
3.Client need to send
this Registration ID, to
our app server. This
registration ID is used
to send data to the
phone.
4.When ever server have
any message for a
particular device , it send
the request to the GCM
server using Registration
ID.

6. You need to create a Google API project open the following link
https://code.google.com/apis/console/
and
activate GCM API service to your project
Note down:
1. Project Number(SENDER ID)
2. API key(Sender Auth Token)

7. Permission:
<manifest package=“in.androidshivendra.gcm" ...>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<permission android:name=“in.androidshivendra.gcm.permission.C2D_MESSAGE"
android:protectionLevel="signature" />
<uses-permission android:name="in.androidshivendra.gcm.permission.C2D_MESSAGE" />
<receiver android:name=".GBroadcastReceiver"
android:permission="com.google.android.c2dm.permission.SEND" >
<intent-filter>
<action android:name="com.google.android.c2dm.intent.RECEIVE" />
<action android:name="com.google.android.c2dm.intent.REGISTRATION" />
<category android:name="in.androidshivendra.gcm" />
</intent-filter>
</receiver>

8. Registration :
Intent registrationIntent = new
Intent("com.google.android.c2dm.intent.REGISTER");
registrationIntent.putExtra("app", PendingIntent.getBroadcast(v.getContext(),
0, new Intent(), 0));
registrationIntent.putExtra("sender", SenderID);
startService(registrationIntent);
Deactivation:
Intent unregIntent = new
Intent("com.google.android.c2dm.intent.UNREGISTER");
unregIntent.putExtra("app", PendingIntent.getBroadcast(v.getContext(), 0, ne
w Intent(), 0));
startService(unregIntent);

9. Create a Broadcaster Receiver class:
GBroadcastReceiver
public class GBroadcastReceiver extends BroadcastReceiver {
public void onReceive(Context context, Intent intent) {
try {
String action = intent.getAction();
if (action.equals("com.google.android.c2dm.intent.REGISTRATION")) {
String registrationId = intent.getStringExtra("registration_id");
String error = intent.getStringExtra("error");
String unregistered = intent.getStringExtra("unregistered");
}
else if (action.equals("com.google.android.c2dm.intent.RECEIVE")) {
String data1 = intent.getStringExtra(“data1");
String data2 = intent.getStringExtra(“data2");
}
} finally {
}}}

10. Processing
(action.equals("com.google.android.c2dm.intent.REGISTRATION"))
String error = intent.getStringExtra("error")
If (error.equals.(“~~~~~~~~~”))
SERVICE_NOT_AVAILABLE The device can't read the response, or there was a
500/503 from the server that can be retried later. The Android application should
use exponential back-off and retry.
•ACCOUNT_MISSING-There is no Google account on the phone. The Android
application should ask the user to open the account manager and add a Google
account. Fix on the device side.
•AUTHENTICATION_FAILED-Bad Google Account password. The Android
application should ask the user to enter his/her Google Account password, and let
the user retry manually later. Fix on the device side.
•INVALID_SENDER-The sender account is not recognized. This must be fixed on
the Android application side. The developer must fix the application to provide the
right sender extra in thecom.google.android.c2dm.intent.REGISTER intent.
PHONE_REGISTRATION_ERROR-Incorrect phone registration with Google.
This phone doesn't currently support
GCM.INVALID_PARAMETERS-The request sent by the phone does not contain
the expected parameters. This phone doesn't currently support GCM.

11. Server implementation is via HTTP request :
To send a message, the application server issues a POST request to
https://android.googleapis.com/gcm/send.
A message request is made of 2 parts:
HTTP header and HTTP body.
The HTTP header
1.Authorization: key=YOUR_API_KEY
2. Content-Type: application/json for JSON; application/x-www-formurlencoded;charset=UTF-8 for plain text.
HTTP Body:
1. registration_id
2. data.<key>

12. Happy Android Programming
By: Shivendra
The Android Trainer