iPhone:在显示/隐藏导航条时不能动画contentInset

In my app, I have a table view. When the user clicks a button, a UIView overlays part of that table view. It's essentially a partial modal. That table view is intentionally still scrollable while that modal is active. To allow the user to scroll to the bottom of the table view, I change the contentInset and scrollIndicatorInsets values to adjust for the smaller area above the modal. When the modal is taken away, I reset those inset values.In my app, I have a table view. When the user c