How to use GCM in Android

 public class GcmBroadcastReceiver extends WakefulBroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
       
        ComponentName comp = new ComponentName(context.getPackageName(),
                GcmIntentService.class.getName());
       
        startWakefulService(context, (intent.setComponent(comp)));
        setResultCode(Activity.RESULT_OK);
    }
}
 

 public class GcmIntentService extends IntentService {
    public static final int NOTIFICATION_ID = 1;
    private NotificationManager mNotificationManager;
    NotificationCompat.Builder builder;
    public static final String SENDER_ID ="write sender id which you have generate earlier";

    public GcmIntentService() {
        super(SENDER_ID);
    }
    
    
    

 // intent come in in your onReceive method of your BroadcastReceiver:
    public void onReceive(Context context, Intent intent) {
       // check to see if it is a message
       if (intent.getAction().equals("com.google.android.c2dm.intent.RECEIVE")) {
          String id = intent.getExtras().getString("id");
          String other_key = intent.getExtras().getString("other_key");

          // if your key/value is a JSON string, just extract it and parse it using JSONObject
          String json_info = intent.getExtras().getString("json_info");
          //JSONObject jsonObj = new JSONObject(json_info);
          Log.d("Message Respinse --->",json_info);
       }
    }
    @Override
    protected void onHandleIntent(Intent intent) {
        Bundle extras = intent.getExtras();
        GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(this);
        String messageType = gcm.getMessageType(intent);

        if (!extras.isEmpty()) {  
            if (GoogleCloudMessaging.
                    MESSAGE_TYPE_SEND_ERROR.equals(messageType)) {
                sendNotification("Send error: " + extras.toString());
            } else if (GoogleCloudMessaging.
                    MESSAGE_TYPE_DELETED.equals(messageType)) {
                sendNotification("Deleted messages on server: " +
                        extras.toString());
            // If it's a regular GCM message, do some work.
            } else if (GoogleCloudMessaging.
                    MESSAGE_TYPE_MESSAGE.equals(messageType)) {
                // This loop represents the service doing some work.
                for (int i=0; i<5; i++) {
                    Log.i("Msg", "Working... " + (i+1)
                            + "/5 @ " + SystemClock.elapsedRealtime());
                    try {
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                    }
                }
                Log.i("Msg", "Completed work @ " + SystemClock.elapsedRealtime());
                // Post notification of received message.
                sendNotification("Received: " + extras.toString());
                Log.i("Msg", "Received: " + extras.toString());
            }
        }
        // Release the wake lock provided by the WakefulBroadcastReceiver.
        GcmBroadcastReceiver.completeWakefulIntent(intent);
    }

    private void sendNotification(String msg) {
        mNotificationManager = (NotificationManager)
                this.getSystemService(Context.NOTIFICATION_SERVICE);

        PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
                new Intent(this, MainActivity.class), 0);

        NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.ic_launcher)
        .setContentTitle("GCM Notification")
        .setStyle(new NotificationCompat.BigTextStyle()
        .bigText(msg))
        .setContentText(msg);

        mBuilder.setContentIntent(contentIntent);
        mNotificationManager.notify(NOTIFICATION_ID, mBuilder.build());
    }
}

 

 public class MainActivity extends Activity {
	public static final String EXTRA_MESSAGE = "message";
    public static final String PROPERTY_REG_ID = "registration_id";
    private static final String PROPERTY_APP_VERSION = "appVersion";
    private final static int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;
    
   
    String SENDER_ID = "project number you got from the API Console";

    static final String TAG = "GCMDemo";

   
    GoogleCloudMessaging gcm;
    AtomicInteger msgId = new AtomicInteger();
    SharedPreferences prefs;
    Context context;

    String regid;

	@SuppressLint("NewApi")
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);


		context = getApplicationContext();

        // Check device for Play Services APK. If check succeeds, proceed with
        //  GCM registration.
        if (checkPlayServices()) {
            gcm = GoogleCloudMessaging.getInstance(this);
            regid = getRegistrationId(context);
            Log.d("Registration ID ",regid+"");

            if (regid.isEmpty()) {
                registerInBackground();
            }
        } else {
            Log.d(TAG, "No valid Google Play Services APK found.");
        }
       
	}
	
	private boolean checkPlayServices() {
	    int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
	    if (resultCode != ConnectionResult.SUCCESS) {
	        if (GooglePlayServicesUtil.isUserRecoverableError(resultCode)) {
	            GooglePlayServicesUtil.getErrorDialog(resultCode, this,
	                    PLAY_SERVICES_RESOLUTION_REQUEST).show();
	        } else {
	            Log.i(TAG, "This device is not supported.");
	            finish();
	        }
	        return false;
	    }
	    return true;
	}
	
	@SuppressLint("NewApi")
	private String getRegistrationId(Context context) {
	    final SharedPreferences prefs = getGCMPreferences(context);
	    String registrationId = prefs.getString(PROPERTY_REG_ID, "");
	    if (registrationId.isEmpty()) {
	        Log.i(TAG, "Registration not found.");
	        return "";
	    }
	    int registeredVersion = prefs.getInt(PROPERTY_APP_VERSION, Integer.MIN_VALUE);
	    int currentVersion = getAppVersion(context);
	    if (registeredVersion != currentVersion) {
	        Log.i(TAG, "App version changed.");
	        return "";
	    }
	    return registrationId;
	}

	private static int getAppVersion(Context context) {
	    try {
	        PackageInfo packageInfo = context.getPackageManager()
	                .getPackageInfo(context.getPackageName(), 0);
	        return packageInfo.versionCode;
	    } catch (NameNotFoundException e) {
	        // should never happen
	        throw new RuntimeException("Could not get package name: " + e);
	    }
	}
	private SharedPreferences getGCMPreferences(Context context) {
	    return getSharedPreferences(MainActivity.class.getSimpleName(),
	            Context.MODE_PRIVATE);
	}
	
	

	  private void registerInBackground() {
	        new AsyncTask() {
	            @Override
	            protected String doInBackground(Void... params) {
	                String msg = "";
	                try {
	                    if (gcm == null) {
	                        gcm = GoogleCloudMessaging.getInstance(context);
	                    }
	                    regid = gcm.register(SENDER_ID);
	                    msg = "Device registered, registration ID=" + regid;
	                    Log.d("Device Reg ID",regid);
	                    storeRegistrationId(context, regid);
	                } catch (IOException ex) {
	                    msg = "Error :" + ex.getMessage();
	                }
	                return msg;
	            }

	            @Override
	            protected void onPostExecute(String msg) {
	            	Toast.makeText(getApplicationContext(), msg,Toast.LENGTH_SHORT).show();
	            }
	        }.execute(null, null, null);
	    }

	
	private void storeRegistrationId(Context context, String regId) {
	    final SharedPreferences prefs = getGCMPreferences(context);
	    int appVersion = getAppVersion(context);
	    Log.i(TAG, "Saving regId on app version " + appVersion);
	    SharedPreferences.Editor editor = prefs.edit();
	    editor.putString(PROPERTY_REG_ID, regId);
	    editor.putInt(PROPERTY_APP_VERSION, appVersion);
	    editor.commit();
	}
	
	

	/**
	 * Receiving push messages
	 * */
	private final BroadcastReceiver mHandleMessageReceiver = new BroadcastReceiver() {
		@Override
		public void onReceive(Context context, Intent intent) {
			String newMessage = intent.getExtras().getString(EXTRA_MESSAGE);
			Toast.makeText(getApplicationContext(), "New Message: " + newMessage, Toast.LENGTH_LONG).show();
			
		}
	};