swift-16进制颜色

func colorWithHexString(hexColor :String) -> UIColor {

        

        if hexColor.isEmpty {

            returnUIColor.clear

        }

     

        var cString = hexColor.trimmingCharacters(in:NSCharacterSet.whitespacesAndNewlines)

        

        // String should be 6 or 8 characters

        if cString.characters.count <6 {

            returnUIColor.clear

        }

        

        // strip 0X if it appears

        if cString.hasPrefix("0X")|| cString.hasPrefix("0x") {

            cString.remove(at: cString.startIndex)

            cString.remove(at: cString.startIndex)

        }

        if cString.hasPrefix("#") {

            cString.remove(at: cString.startIndex)

        }

        

        if cString.characters.count !=6 {

            returnUIColor.clear

        }

        

        let rRange = cString.startIndex ..< cString.index(cString.startIndex, offsetBy: 2)

        let rString = cString.substring(with: rRange)

        

        let gRange = cString.index(cString.startIndex, offsetBy:2) ..< cString.index(cString.startIndex, offsetBy:4)

        let gString = cString.substring(with: gRange)

        

        let bRange = cString.index(cString.startIndex, offsetBy:4) ..< cString.index(cString.startIndex, offsetBy:6)

        let bString = cString.substring(with: bRange)

        

        var r :UInt32  = 0

        var g :UInt32  = 0

        var b :UInt32  = 0

        let rScanner:Scanner =Scanner.localizedScanner(with: rString)as! Scanner

        rScanner.scanHexInt32(&r)

        let gScanner:Scanner =Scanner.localizedScanner(with: gString)as! Scanner

        gScanner.scanHexInt32(&g)

        let bScanner:Scanner =Scanner.localizedScanner(with: bString)as! Scanner

        bScanner.scanHexInt32(&b)

        

        let color =UIColor(red: CGFloat(r)/255.0, green:CGFloat(g)/255.0, blue:CGFloat(b)/255.0, alpha:1.0)

        

        

        return color

    }