objective-c - about self.view.frame

Question

I have source allowing rotate interfaceOrientation. (in viewDidLoad)

CGPoint point;
NSInteger itemCount;

if (self.interfaceOrientation == UIInterfaceOrientationPortrait || self.interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
point.x = (self.view.frame.size.width - (100 * itemCount)) / 2
else
...    

In spite of running simulator in UIInterfaceOrientationLandscapeLeft mode, I have 768 pixel of self.view.frame.size.width (on iPad) so I can't have appropriate value of point.x

How I can access self.view.frame on rotating?