问题:

I have an app that uses the iPhone's contacts. With iOS 6, the user will be prompted for Contact access on the first try. At this point, the user can hit 'Allow' or 'Don't Allow'. The problem is when the user backgrounds the app, and then navigates to Settings->Privacy->Contacts to toggle the Contact privacy setting for my app. Once it is toggled, I can see on the console that my app:

Application 'UIKitApplication:com.myApp' exited abnormally with signal 9: Killed: 9

I can't find any information on this in Apple's documentation. Does anyone know a way to prevent this? Is this as designed? Or is this an Apple bug?

回答1:

the OS sends a SIGKILL which is not a crash - Apple session on privacy in iOS6 says:

If permissions changes, app is quit.
Background task expiration handler is called, if registered
iOS then kills the application.

WWDC 2012 Session Videos: Privacy Support in iOS and OS X

Expiration handler: beginBackgroundTaskWithExpirationHandler

There is no way around this I can see.

回答2:

After testing beginBackgroundTaskWithExpirationHandler I can say that expiration handler block is not called after changing permission settings as stated in Apple presentation.