title: iPhone SDK: Examining view size within UINavigationController
body: <p>My application has a tab bar, and in one tab I have a navigation controller.</p>
  
  <p>I want to find the position of the center of the view that appears between the navigation bar and tab bar, so that I can display a UIActivityIndicatorView right in the middle of the view when stuff happens.</p>
  
  <p>However, I'm getting different values of <code>self.view.bounds.size</code> depending on where I am in the navigation hierarchy.  At the top level, it tells me 320x460 but it's 320x367 in deeper levels.</p>
  
  <p>320x367 is the size I'm expecting (and confirmed in IB by the size inspector).  So why am I seeing different on the top level only?</p>