Question

My app registers for background location updates (not Significant Change. I need more granularity than kilometers)

That part works fine. I just want to stop the updates after the app has been in the background for 60 minutes. The way I’m doing it right now is to call stopUpdatingLocation in my CLLocationManager delegate.

However, I am unsure if this will actually stop my app from receiving background location updates, or if it will, but will just ignore them. Ideally, I’d like to not have my app be responsible for battery drain except for a small period of time after user activity.

Apple’s documentation tends to send me in circles on this one. Right when I think “Executing Code in the Background” is about to spill the answer, it directs me to “Location Awareness Programming Guide.” Right when that one is about to get specific about this question, it sends me back to “Executing Code in the Background.” 🙂

Answer 1

I’m not sure whether your app has total control over this, but the docs for stopUpdatingLocation do state the following …

Disabling event delivery gives the receiver the option of disabling the appropriate hardware (and thereby saving power) when no clients need location data

Which would suggest that should your app be the only one requesting background location data, and you request it to stop the GPS receiver would disable the appropriate hardware to save on power, which I think it was you’re looking for.

What I can suggest is that you enable Power logging in Settings -> Developer, then run your app for an hour or so to a point where you think GPS is disabled, run for another hour and then compare the power usage in Instruments. This should provide you with a much clearer picture.