let color = UIColor.redColor().CGColor
let numComponents = CGColorGetNumberOfComponents(color)
if numComponents == 4 {
let components = CGColorGetComponents(color)
let red = components[0]
let green = components[1]
let blue = components[2]
let alpha = components[3]
}
原文链接：iOS Color Hex RGB，转载请注明来源！