title: Custom UIView with keyboard input?
body: <p>I have a custom UILabel subclass for displaying currency values. I only want the user to be able to enter digits and let the view format those digits into a currency value -- like a cash register. This makes UITextField an inappropriate choice for this kind of input.</p>
  
  <p>I've already overridden hitTest: so that the UILabel will return itself -- this is apparently a bug. Also, I've overridden both canBecomeFirstResponder and becomeFirstResponder to return YES. Neither of these methods are being called, though.</p>
  
  <p>I only want to let the user type numbers and use the backspace key. I've implemented UITextInputTraits, but the keyboard does not appear. So, can this be done? And does if so, what am I missing?</p>