1. Difference between Service and IntentService
Service: It is the base class for the Android services, that you can extend for creating any service.
Since the service run inside the UI thread, it requires that you create a working thread for executing its work.
IntentService: it is a subclass of Service, that simplifies your work. It works already in a working thread, and can receive asynchronous requests. So, you don't need to create it manually, or to worry about synchronization. You can simply extend it and override the method:
onHandleIntent(Intent intent)
where you can manage all the incoming requests.
Taking a look at the documentation, you can see in details what the IntentService do for you:
- Creates a default worker thread that executes all intents delivered to
onStartCommand() separate from your application's main thread.
- Creates a work queue that passes one intent at a time to your
onHandleIntent() implementation, so you never have to worry about multi-threading.
- Stops the service after all start requests have been handled, so you never have to call
stopSelf().
- Provides default implementation of
onBind() that returns null.
- Provides a default implementation of
onStartCommand() that sends the intent to the work queue and then to your onHandleIntent() implementation.
So, if you need more control you can use the Service class, but often for a simple service the best solution is the IntentService.
2. Difference between AsyncTask and Service
They are two different concepts.
Service: can be intended as an Activity with no interface. It is suitable for long-running operations.
AsyncTask: is a particular class that wraps a working thread (performing background operations), facilitating the interaction with the UI Thread, without managing threads or handlers directly.
