How to kill an android service?

Question

I'm writing an app which has a long-running service.

I've written some state-saving code in the service's onDestroy method.

My intention is that this should be invoked if the service ever gets killed by Android, due to memory pressure.

How can I simulate the service being killed by memory pressure?

I've tried adb shell am force-stop com.example.app but the service's onDestroy method was not invoked.

Is onDestroy a sensible site for service-shutdown-state-saving?

If so, how can I make a service's onDestroy be invoked by Android, for debugging/testing purposes?

"How can I simulate the service being killed by memory pressure?" -- a service is never "killed by memory pressure". The entire process is terminated due to memory pressure. Whether that triggers `onDestroy()` or not depends a bit on environmental considerations. "how can I make a service's onDestroy be invoked by Android?" -- call `stopService()` from your test suite, with an `Intent` identifying your service. — CommonsWare, Sep 16 '15 at 20:17
@CommonsWare "Whether that triggers onDestroy() or not depends a bit on environmental considerations." If `onDestroy` is not always called, where should I site the state-saving code? — fadedbee, Sep 16 '15 at 20:18
"If onDestroy is not always called, where should I site the state-saving code?" -- at the point when the state changes. — CommonsWare, Sep 16 '15 at 20:20
I have seen a similar solution here - http://stackoverflow.com/questions/3117095/stopping-an-android-app-from-console Also, I guess none of the method will be executed when the app crashes so you can handle it in an uncaught exception. Refer this http://stackoverflow.com/questions/19945407/can-i-call-a-method-before-my-application-go-to-crash — Techidiot, Sep 16 '15 at 20:21

sergej shafarenka · Accepted Answer · 2015-09-18T08:55:36.667

You should not rely on onDestroy() because it only gets called, when service is properly stopped (by calling stopService() or stopSelf() method).

If you want to save service state, you should either save it as you go (for instance a player service can store it when play/pause function is activated), or use a timer to save it periodically.

If you want to react to memory events, you should use ComponentCallbacks2 class, which will notify you, when Android needs more memory. If you free memory inside those callbacks, you will increase probability your service will stay in memory longer.

Hope this helps.

score 1 · Answer 2 · answered Sep 16 '15 at 20:18

1

If you want to programmatically stop your Service, within the Service, call stopSelf().

Alternatively go to the app settings and do a force stop.

answered Sep 16 '15 at 20:18

akodiakson

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Sorry, where are the "app settings" (Android 4.0.3) – fadedbee Sep 16 '15 at 20:20
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How would you uninstall an app? Usually there's a screen dedicated to that and has a "FORCE STOP" option. – akodiakson Sep 16 '15 at 20:21
I use `adb shell pm uninstall com.example.app`, or google play, to uninstall an app. I've not yet seen screen where I can uninstall an app on the phone. – fadedbee Sep 16 '15 at 20:23
Found it, thanks - a long press of the home button brought up a list of the activities. – fadedbee Sep 16 '15 at 20:25
FORCE STOP did not cause onDestroy to fire :( – fadedbee Sep 16 '15 at 20:26
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Android will kill Services impolitely like @Commonsware says. Impolitely meaning onDestroy won't be invoked. – akodiakson Sep 16 '15 at 20:30

score 1 · Answer 3 · answered Sep 16 '15 at 20:36

A force stop will not call onDestroy on any components, neither service nor activity. It completely closes the app without any further considerations.

I'm not sure about this but if your service isn't running as foreground service you can close it by removing the app from recent apps menu.

How to kill an android service?

3 Answers3