title: How do I apply a numeric input mask to a UITextField in Objective-c
body: <p>I have a TextField which I would only like the end user to enter monetary values into, e.g. 20000. I would like the field to automatically display the entered numbers with a display mask, so that when the user enters the keystrokes it changes the field contents dynamically. E.g. 2000050 entered would display as 20,000.50.</p>