Android APIs
public abstract class

IntentService

extends Service
java.lang.Object
   ↳ android.content.Context
     ↳ android.content.ContextWrapper
       ↳ android.app.Service
         ↳ android.app.IntentService

Class Overview

IntentService is a base class for Services that handle asynchronous requests (expressed as Intents) on demand. Clients send requests through startService(Intent) calls; the service is started as needed, handles each Intent in turn using a worker thread, and stops itself when it runs out of work.

This "work queue processor" pattern is commonly used to offload tasks from an application's main thread. The IntentService class exists to simplify this pattern and take care of the mechanics. To use it, extend IntentService and implement onHandleIntent(Intent). IntentService will receive the Intents, launch a worker thread, and stop the service as appropriate.

All requests are handled on a single worker thread -- they may take as long as necessary (and will not block the application's main loop), but only one request will be processed at a time.

Developer Guides

For a detailed discussion about how to create services, read the Services developer guide.

See Also

Summary

[Expand]
Inherited Constants
From class android.app.Service
From class android.content.Context
From interface android.content.ComponentCallbacks2
Public Constructors
IntentService(String name)
Creates an IntentService.
Public Methods
IBinder onBind(Intent intent)
Unless you provide binding for your service, you don't need to implement this method, because the default implementation returns null.
void onCreate()
Called by the system when the service is first created.
void onDestroy()
Called by the system to notify a Service that it is no longer used and is being removed.
void onStart(Intent intent, int startId)
int onStartCommand(Intent intent, int flags, int startId)
You should not override this method for your IntentService.
void setIntentRedelivery(boolean enabled)
Sets intent redelivery preferences.
Protected Methods
abstract void onHandleIntent(Intent intent)
This method is invoked on the worker thread with a request to process.
[Expand]
Inherited Methods
From class android.app.Service
From class android.content.ContextWrapper
From class android.content.Context
From class java.lang.Object
From interface android.content.ComponentCallbacks2
From interface android.content.ComponentCallbacks

Public Constructors

public IntentService (String name)

Added in API level 3

Creates an IntentService. Invoked by your subclass's constructor.

Parameters
name Used to name the worker thread, important only for debugging.

Public Methods

public IBinder onBind (Intent intent)

Added in API level 3

Unless you provide binding for your service, you don't need to implement this method, because the default implementation returns null.

Parameters
intent The Intent that was used to bind to this service, as given to Context.bindService. Note that any extras that were included with the Intent at that point will not be seen here.
Returns
  • Return an IBinder through which clients can call on to the service.
See Also

public void onCreate ()

Added in API level 3

Called by the system when the service is first created. Do not call this method directly.

public void onDestroy ()

Added in API level 3

Called by the system to notify a Service that it is no longer used and is being removed. The service should clean up any resources it holds (threads, registered receivers, etc) at this point. Upon return, there will be no more calls in to this Service object and it is effectively dead. Do not call this method directly.

public void onStart (Intent intent, int startId)

Added in API level 3

This method is deprecated.
Implement onStartCommand(Intent, int, int) instead.

public int onStartCommand (Intent intent, int flags, int startId)

Added in API level 5

You should not override this method for your IntentService. Instead, override onHandleIntent(Intent), which the system calls when the IntentService receives a start request.

Parameters
intent The Intent supplied to startService(Intent), as given. This may be null if the service is being restarted after its process has gone away, and it had previously returned anything except START_STICKY_COMPATIBILITY.
flags Additional data about this start request. Currently either 0, START_FLAG_REDELIVERY, or START_FLAG_RETRY.
startId A unique integer representing this specific request to start. Use with stopSelfResult(int).
Returns
  • The return value indicates what semantics the system should use for the service's current started state. It may be one of the constants associated with the START_CONTINUATION_MASK bits.

public void setIntentRedelivery (boolean enabled)

Added in API level 5

Sets intent redelivery preferences. Usually called from the constructor with your preferred semantics.

If enabled is true, onStartCommand(Intent, int, int) will return START_REDELIVER_INTENT, so if this process dies before onHandleIntent(Intent) returns, the process will be restarted and the intent redelivered. If multiple Intents have been sent, only the most recent one is guaranteed to be redelivered.

If enabled is false (the default), onStartCommand(Intent, int, int) will return START_NOT_STICKY, and if the process dies, the Intent dies along with it.

Protected Methods

protected abstract void onHandleIntent (Intent intent)

Added in API level 3

This method is invoked on the worker thread with a request to process. Only one Intent is processed at a time, but the processing happens on a worker thread that runs independently from other application logic. So, if this code takes a long time, it will hold up other requests to the same IntentService, but it will not hold up anything else. When all requests have been handled, the IntentService stops itself, so you should not call stopSelf().

Parameters
intent The value passed to startService(Intent).