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GoogleCloudMessaging

public class GoogleCloudMessaging extends Object
java.lang.Object
   ↳ com.google.android.gms.gcm.GoogleCloudMessaging

GoogleCloudMessaging (GCM) enables apps to communicate with their app servers using simple messages.

To send or receive messages, the app must get a registrationToken from getToken(String, String), which authorizes an app server to send messages to an app instance. Pass sender ID and INSTANCE_ID_SCOPE as parameters to the method. A sender ID is a project number acquired from the API console, as described in Getting Started.

In order to receive GCM messages, declare GcmReceiver and an implementation of GcmListenerService in the app manifest. GcmReceiver will pass the incoming messages to the implementation of GcmListenerService. To process messages, override base class methods to handle any events required by the application.

Client apps can send upstream messages back to the app server using the XMPP-based Cloud Connection Server, For example:

 gcm.send(SENDER_ID + "@gcm.googleapis.com", id, data);

See Implementing GCM Client for more details.

Constant Summary

String ERROR_MAIN_THREAD The GCM register() and unregister() methods are blocking.
String ERROR_SERVICE_NOT_AVAILABLE The device can't read the response, or there was a 500/503 from the server that can be retried later.
String INSTANCE_ID_SCOPE Specifies scope used in obtaining GCM registrationToken when calling getToken(String, String)
String MESSAGE_TYPE_DELETED This constant is deprecated. Instead implement onDeletedMessages()
String MESSAGE_TYPE_MESSAGE This constant is deprecated. Instead implement onMessageReceived(String, Bundle)
String MESSAGE_TYPE_SEND_ERROR This constant is deprecated. Instead implement onSendError(String, String)
String MESSAGE_TYPE_SEND_EVENT This constant is deprecated. Instead implement onMessageSent(String)

Public Constructor Summary

Public Method Summary

void
close()
synchronized static GoogleCloudMessaging
getInstance(Context context)
String
synchronized String
register(String... senderIds)
This method is deprecated. Instead, for GCM registration, use InstanceID.getToken(). Set authorizedEntity to a sender ID and scope to INSTANCE_ID_SCOPE.
void
send(String to, String msgId, long timeToLive, Bundle data)
void
send(String to, String msgId, Bundle data)
synchronized void
unregister()
This method is deprecated. Instead use InstanceID.deleteToken() or InstanceID.deleteInstanceID().

Constants

public static final String ERROR_MAIN_THREAD

The GCM register() and unregister() methods are blocking. Blocking methods must not be called on the main thread.

Constant Value: "MAIN_THREAD"

public static final String ERROR_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 application should use exponential back off and retry.

Constant Value: "SERVICE_NOT_AVAILABLE"

public static final String INSTANCE_ID_SCOPE

Specifies scope used in obtaining GCM registrationToken when calling getToken(String, String)

Constant Value: "GCM"

public static final String MESSAGE_TYPE_DELETED

This constant is deprecated.
Instead implement onDeletedMessages()

Returned by getMessageType(Intent) to indicate that the server deleted some pending messages because they exceeded the storage limits. The application should contact the server to retrieve the discarded messages.

Constant Value: "deleted_messages"

public static final String MESSAGE_TYPE_MESSAGE

This constant is deprecated.
Instead implement onMessageReceived(String, Bundle)

Returned by getMessageType(Intent) to indicate a regular message.

Constant Value: "gcm"

public static final String MESSAGE_TYPE_SEND_ERROR

This constant is deprecated.
Instead implement onSendError(String, String)

Returned by getMessageType(Intent) to indicate a send error. The intent includes the message ID of the message and an error code.

Constant Value: "send_error"

public static final String MESSAGE_TYPE_SEND_EVENT

This constant is deprecated.
Instead implement onMessageSent(String)

Returned by getMessageType(Intent) to indicate a sent message has been received by the GCM server. The intent includes the message ID of the message.

Constant Value: "send_event"

Public Constructors

public GoogleCloudMessaging ()

Public Methods

public void close ()

Must be called when your application is done using GCM, to release internal resources.

public static synchronized GoogleCloudMessaging getInstance (Context context)

Return the singleton instance of GCM.

public String getMessageType (Intent intent)

Return the message type from an intent passed into a client app's broadcast receiver. There are two general categories of messages passed from the server: regular GCM messages, and special GCM status messages. The possible types are:

You can use this method to filter based on message type. Since it is likely that GCM will be extended in the future with new message types, just ignore any message types you're not interested in, or that you don't recognize.

Returns
  • The message type or null if the intent is not a GCM intent

public synchronized String register (String... senderIds)

This method is deprecated.
Instead, for GCM registration, use InstanceID.getToken(). Set authorizedEntity to a sender ID and scope to INSTANCE_ID_SCOPE.

Register the application for GCM and return the registration ID. You must call this once, when your application is installed, and send the returned registration ID to the server.

Repeated calls to this method will return the original registration ID.

If you want to modify the list of senders, you must call unregister() first.

Most applications use a single sender ID. You may use multiple senders if different servers may send messages to the app or for testing.

Parameters
senderIds list of project numbers or Google accounts identifying who is allowed to send messages to this application.
Returns
  • registration id
Throws
IOException

public void send (String to, String msgId, long timeToLive, Bundle data)

Send an upstream ("device to cloud") message. You can only use the upstream feature if your GCM implementation uses the XMPP-based Cloud Connection Server. The current limits for max storage time and number of outstanding messages per application are documented in the GCM Developers Guide.

Parameters
to string identifying the receiver of the message in the format of SENDER_ID@gcm.googleapis.com. The SENDER_ID should be one of the sender IDs used when calling getToken(String, String)
msgId ID of the message. This is generated by the application. It must be unique for each message. This allows error callbacks and debugging.
timeToLive If 0, we'll attempt to send immediately and return an error if we're not connected. Otherwise, the message will be queued. As for server-side messages, we don't return an error if the message has been dropped because of TTL—this can happen on the server side, and it would require extra communication.
data key/value pairs to be sent. Values must be String, any other type will be ignored.

public void send (String to, String msgId, Bundle data)

Send an upstream ("device to cloud") message. You can only use the upstream feature if your GCM implementation uses the XMPP-based Cloud Connection Server. When there is an active connection the message will be sent immediately, otherwise the message will be queued for the maximum interval.

Parameters
to string identifying the receiver of the message in the format of SENDER_ID@gcm.googleapis.com. The SENDER_ID should be one of the sender IDs used when calling getToken(String, String)
msgId ID of the message. This is generated by the application. It must be unique for each message. This allows error callbacks and debugging.
data key/value pairs to be sent. Values must be String—any other type will be ignored.
Throws
IllegalArgumentException
IOException

public synchronized void unregister ()

This method is deprecated.
Instead use InstanceID.deleteToken() or InstanceID.deleteInstanceID().

Unregister the application. Calling unregister() stops any messages from the server. This is a blocking call—you shouldn't call it from the UI thread. You should rarely (if ever) need to call this method. Not only is it expensive in terms of resources, but it invalidates all your registration IDs returned from register() or subscribe(). This should not be done unnecessarily. A better approach is to simply have your server stop sending messages.

Throws
IOException if we can't connect to server to unregister.