I'm writing a program for iPhone that will first let the user take a photo, then will dynamically retrieve a colour of the place where the user taps on the image, and draw a rectangle of that colour. I have two relevant classes for this: `AppViewController` and `AppView`. The former contains all the UI elements and IBActions, the latter the position of last tap, the touches-handling methods and the `drawRect` (and a static method to get colour data at a given coords of an image). 

What I wanted to do is to put the touch-handling (calling `drawRect` in `touchesMoved`/`Ended`) and the `drawRect` in the `AppViewController`. That doesn't work, since that class doesn't inherit from `UIView`, but from `UIViewController`. What's the correct way to do that?

Another way to phrase that: How to constantly change something (well, constantly as long as the user is swiping across the screen) in a class that doesn't support touch-detection methods?

(This probably doesn't explain it well. Please ask clarifying questions).