[iOS][Swift]Storyboardでボタン背景色の設定がしたい ref: http://qiita.com/wasnot/items/3537d932e9550a5c4c27

BackgroundHighlightedButton.swift

class BackgroundHighlightedButton: UIButton {
    @IBInspectable var highlightedBackgroundColor :UIColor?
    @IBInspectable var nonHighlightedBackgroundColor :UIColor?
    override var highlighted :Bool {
        didSet {
            if highlighted {
                self.backgroundColor = highlightedBackgroundColor
            }
            else {
                self.backgroundColor = nonHighlightedBackgroundColor
            }
        }
    }
}

file1.swift

extension UIButton {
    private func imageWithColor(color: UIColor) -> UIImage {
        let rect = CGRectMake(0.0, 0.0, 1.0, 1.0)
        UIGraphicsBeginImageContext(rect.size)
        let context = UIGraphicsGetCurrentContext()

        CGContextSetFillColorWithColor(context, color.CGColor)
        CGContextFillRect(context, rect)

        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return image
    }

    func setBackgroundColor(color: UIColor, forUIControlState state: UIControlState) {
        self.setBackgroundImage(imageWithColor(color), forState: state)
    }
}