The Android Service class is designed specifically to allow applications to initiate and perform background tasks. Unlike broadcast receivers, which are intended to perform a task quickly and then exit, services are designed to perform tasks that take a long time to complete (such as downloading a file over an internet connection or streaming music to the user) but do not require a user interface.
In this chapter, an overview of the different types of services available will be covered, including started services, bound services and intent services. Once these basics have been covered, subsequent chapters will work through a number of examples of services in action.
== Intent Service ==
As previously outlined, services run by default within the same main thread as the component from which they are launched. As such, any CPU intensive tasks that need to be performed by the service should take place within a new thread, thereby avoiding impacting affecting the performance of the calling application.
The IntentService class is a convenience class (subclassed from the Service class) that sets up a worker thread for handling background tasks and handles each request in an asynchronous manner. Once the service has handled all queued requests , it simply exits. All that is required when using the IntentService class is that the onHandleIntent() method be implemented containing the code to be executed for each request.
