A service is a general-purpose entry point for keeping an app running in the background for all kinds of reasons. It is a component that runs in the background to perform long-running operations or to perform work for remote processes.
A service does not provide a UI.
- Only one instance of specific service is allow to run at the same time.
- The Service and IntentService may be triggered from any thread, activity or other application component.
- Use
bindService()when need to communicate between activity and service (thru service connection). START_STICKYexplicit started and stop aas needed,START_NOT_STICKYtell OS not to re-start service again when have enough memory (when service was killed before due to device run out of memory)
| Service | IntentService |
|---|---|
| used in tasks with no UI, but shouldn't be too long ( If need to perform long or heavy tasks, must use threads within Service) | used in long tasks usually with no communication to main UI thread |
| Main thread | New worker thread |
| Block main thread | Cannot run task in parallel. Hence all the consecutive intents will go into the message queue for the worker thread and will execute sequentially |
Must call stopSelf() or stopService() if not use bounded service |
Do not have to call, auto shutdown after all start requests have been handled |
- For performance related stuffs of
IntentServicesee this.