Service VS IntentService in Android
September 11, 2013
In the official documentation of Android, Service and IntentService are described as follows:
This is the base class for all services. When you extend this class, it’s important that you create a new thread in which to do all the service’s work, because the service uses your application’s main thread, by default, which could slow the performance of any activity your application is running.
This is a subclass of Service that uses a worker thread to handle all start requests, one at a time. This is the best option if you don’t require that your service handle multiple requests simultaneously. All you need to do is implement
onHandleIntent(), which receives the intent for each start request so you can do the background work.
Below are some key differences between Service and IntentService in Android.
1) When to use?
Service can be used in tasks with no UI, but shouldn’t be too long. If you need to perform long tasks, you must use threads within Service.
IntentService can be used in long tasks usually with no communication to Main Thread. If communication is required, can use Main Thread handler or broadcast intents. Another case of use is when callbacks are needed (Intent triggered tasks).
2) How to trigger?
Service is triggered calling to method
IntentService is triggered using an Intent, it spawns a new worker thread and the method
onHandleIntent() is called on this thread.
3) Triggered From
Service may be triggered from any thread.
IntentService must be triggered from Main Thread.
### 4) Runs On
Service runs in background but it runs on the Main Thread of the application.
IntentService runs on a separate worker thread.
5) Limitations / Drawbacks
Service may block the Main Thread of the application.
IntentService cannot run tasks in parallel. Hence all the consecutive intents will go into the message queue for the worker thread and will execute sequentially.