UIColor

A UIColor object represents color and sometimes opacity (alpha value). You can use UIColor objects to store color data, and during drawing you can use them to set the current fill and stroke colors.
Many methods in UIKit require you to specify color data using a UIColor object, and for general color needs it should be your main way of specifying colors.

In the coming exercise, Change UIView.backgroundColor using UIColor, I will create a simple iPhone application to change UIView.backgroundColor using UIColor.