UIColor hex value extension in Swift.

UIColorHexValue

import UIKit

extension UIColor
{
    func hexString() -> String?
    {
        var redValue: CGFloat = 0
        var greenValue: CGFloat = 0
        var blueValue: CGFloat = 0
        var alphaValue: CGFloat = 0
        
        if self.getRed(&redValue, green: &greenValue, blue: &blueValue, alpha: &alphaValue) {
            
            let r = Int(redValue * 255.0)
            let g = Int(greenValue * 255.0)
            let b = Int(blueValue * 255.0)
            
            return "#"+String(format: "%02X", Int(r))+String(format: "%02X", Int(g))+String(format: "%02X", Int(b))
            
        } else {
            return nil
        }
    }
}