UIColor extension for HexColor

UIColor+Hex.swift

extension UIColor {
    convenience init(hex string: String, alpha: CGFloat) {
        let hex = string.replacingOccurrences(of: "#", with: "")
        let scanner = Scanner(string: hex)
        var color: UInt32 = 0
        if scanner.scanHexInt32(&color) {
            let r = CGFloat((color & 0xFF0000) >> 16) / 255.0
            let g = CGFloat((color & 0x00FF00) >> 8) / 255.0
            let b = CGFloat(color & 0x0000FF) / 255.0
            self.init(red: r, green: g, blue: b, alpha: alpha)
        } else {
            self.init(white: 1.0, alpha: 1)
        }
    }

    var hex: String {
        var r: CGFloat = 0
        var g: CGFloat = 0
        var b: CGFloat = 0
        var a: CGFloat = 0
        getRed(&r, green: &g, blue: &b, alpha: &a)
        let rgb = Int(r * 255) << 16 | Int(g * 255) << 8 | Int(b * 255) << 0
        return String(format: "#%06x", rgb).uppercased()
    }
}