How does the Navita TEM app get call log information?

Question

How does Navita https://itunes.apple.com/us/app/navita-t.e.m.-personal/id590228620?mt=8 manage to display a call log?

If I swipe the app out of the task manager then it

Answer 1

If you are observing the call center while the app is in the background you get a set of updates when the app is brought back to the foreground. This set of data may not be as accurate as if the app had been mostly in the foreground but it does include quite a bit of info.

Answer 2

Here is what I've found from Navita TEM disassembly and it's resources.

Application uses two background modes - location and audio. You can see it in the Info.plist file. When you enable phone calls logging application will also enable "alerts" and "Real-time" switches. When "alerts" enabled application infinitely loops in background "bg-sound.mp3" file which has no sound, it's just silence. Because of that it doesn't use hacks like this one How to get a call event using CTCallCenter:setCallEventHandler: that occurred while the app was suspended? . It's similar trick to location used in order to keep the app running in background and receive phone call events. Somehow this was not rejected from the AppStore.