iphone status bar activity indicator spins forever
The Cause
I can reproduce this problem consistently on iOS 7.1.1. Just go into App Store and click the &quot;update all&quot; button in the updates tab. When you exit to your home screen, the activity indicator will spin in the status bar incessantly. Since the code has been wedged into the wrong state, the only way to get rid of the activity indicator is to power down your phone and boot it back up.
The Reason
This is caused by Apple developers poor programming. They properly show it when apps begin to update:
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

But they fail to turn it off when the apps finish updating:
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

The way their Cocoa Touch framework is written makes it very easy for amateur developers to make this mistake, including Apple's own internal iOS development team. It's very hard to manage nested network operations that need to show the activity indicator. The correct interface for managing the activity indicator would have been to create a stack. Any time the indicator is needed, an object would be pushed onto the stack. When the operation is complete, the object would be popped from the stack. Once the stack is empty, the indicator should disappear.