Set the navigation bar's translucent property to NO:
self.navigationController.navigationBar.translucent = NO;
This will fix the view from being framed underneath the navigation bar and status bar.
If you have to show and hide the navigation bar, then use
if ([self respondsToSelector:@selector(edgesForExtendedLayout)])
self.edgesForExtendedLayout = UIRectEdgeNone; // iOS 7 specific
in your viewDidLoad
method.