Question

I would like to run a process in the background of my application that gets the user’s current latitude/longitude (at 5 minute intervals) and reports it back to our server via web service call. When I add required background modes to my info.plist I have the following options:

-App plays audio

-App registers for location updates

-App provides Voice over IP services

Now in my case I obviously need the second choice on the list, but once I have the location what can I do with it? Can I make a web service call in the background?? What other limitations might there be??

Thanks a lot!

Answer 1

When you App is in background mode you can not establish a HTTP connection the usual way. You have to setup a background task that sends the location updates to your server.

I found a short tutorial that covers exactly what you’re looking for (I’ve not tested the code).

This is a summary of how it works
When your App is running in background and a location change occurs, iOS wakes up your App and calls the delegate method locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation of your CLLocationManager. When this happens, check if your App is running in the background and setup the background task if it is. The background task then should send the data to your server.

Limitations

• The documentation is not clear about how much time such a background task may take to finish, but I slightly remember it was something around 10 minutes maximum.

• As far as I know you can not update the UI while your App runs in the
  background