Open Radar

 
Summary:
Hiding or showing the status bar using -[UIApplication setStatusBarHidden:withAnimation] does not result in KVO notifications for observers of the "statusBarHidden" property. Only -[UIApplication setStatusBarHidden:] results in KVO notifications.

Steps to Reproduce:
1. Add an object as an observer to UIApplication's "statusBarHidden" key path.
2. Call -[UIApplication setStatusBarHidden:withAnimation:] somewhere else in the code.

Expected Results:
The observing object's -observeValueForKeyPath:ofObject:change:context: method is called after the animation completes – or – some other mechanism is provided for notifying interested objects that the status bar has been shown/hidden.

Actual Results:
The observing object's -observeValueForKeyPath:ofObject:change:context: method is never called

Regression:
No

Notes:
See attached sample project. My root view controller observes UIApplication's "statusBarHidden" property response to changes by resizing itself. Tapping the top button calls -[UIApplication setStatusBarHidden:] and the view is resized correctly. Tapping the bottom button calls -[UIApplication setStatusBarHidden:withAnimation] and the view is not resized.