十六进制字符串&RGB&UIColor转换~~Swift

文章仅供参考，如有更好的编写方法，欢迎指正！！！
XFJColor.swift文件

import UIKit

class XFJColor: NSObject {
    
    /**
     * RGB转UIColor
     * R : 红
     * G : 绿
     * B : 蓝
     * A : 透明度(默认透明度为1)
     * Return : UIColor
     */
    func colorWithRGB(r: CGFloat, g: CGFloat, b: CGFloat, a: CGFloat = 1.0) -> UIColor {
        print(String(format: "R:%f", r), String(format: "G:%f", g), String(format: "B:%f", b), String(format: "A:%f", a))
        let color : UIColor = UIColor.init(red: (r / 255.0), green: (g / 255.0), blue: (b / 255.0), alpha: a)
        return color
    }
    
    /**
     * 十六进制字符串转换UIColor
     * Hex : 十六进制字符串
     * A : 透明度(默认透明度为1)
     * Return : UIColor
     */
    func colorWithHexString(hex: String, a:CGFloat = 1.0) -> UIColor {
        var cString : String = hex.trimmingCharacters(in: NSCharacterSet.whitespacesAndNewlines)
        // String should be 6 or 8 characters
        if cString.count < 6 {
            return UIColor.clear
        }
        // 判断前缀
        if cString.hasPrefix("0x") {
            cString.removeFirst(2)
        }
        if cString.hasPrefix("0X") {
            cString.removeFirst(2)
        }
        if cString.hasPrefix("#") {
            cString.removeFirst(1)
        }
        if cString.count != 6 {
            return UIColor.clear
        }
        // 从六位数值中找到RGB对应的位数并转换
        let mask = 0x000000FF
        let r: Int
        let g: Int
        let b: Int
        
        let red: CGFloat
        let green: CGFloat
        let blue: CGFloat
        if #available(iOS 13.0, *) {
            // 系统版本高于13.0
            var color: UInt64 = 0
            let scanner = Scanner(string: cString)
            scanner.scanHexInt64(&color)
            
            
             r = Int(color >> 16) & mask
             g = Int(color >> 8) & mask
             b = Int(color) & mask
            
             red   = CGFloat(r)
             green = CGFloat(g)
             blue  = CGFloat(b)
            
        } else {
            // 系统版本低于13.0
            var color: UInt32 = 0
            let scanner = Scanner(string: cString)
            scanner.scanHexInt32(&color)

             r = Int(color >> 16) & mask
             g = Int(color >> 8) & mask
             b = Int(color) & mask
            
             red   = CGFloat(r)
             green = CGFloat(g)
             blue  = CGFloat(b)
            
        }
        
        return self.colorWithRGB(r: red, g: green, b: blue, a: a)
    }
    
    /**
     * UIColor转十六进制字符串
     * Color : UIColor
     * Perfix : 返回十六进制字符串格式(默认#)
     * Return : 十六进制字符串(如果UIColor透明度小于1，返回值含有透明度)
     */
    func hexFromUIColor(color: UIColor, perfix: String = "#") -> String {
        var red: CGFloat = 0
        var green: CGFloat = 0
        var blue: CGFloat = 0
        var alpha: CGFloat = 0
        
        let multiplier = CGFloat(255.999)
        
        // 判断当前UIColor是否存在并且映射
        // 如果不存在执行guard里面
        guard color.getRed(&red, green: &green, blue: &blue, alpha: &alpha) else {
            return ""
        }

        if alpha == 1.0 {
            return String(
                format: "%@%02lX%02lX%02lX",
                perfix,
                Int(red * multiplier),
                Int(green * multiplier),
                Int(blue * multiplier)
            )
        } else {
            return String(
                format: "%@%02lX%02lX%02lX%.2f",
                perfix,
                Int(red * multiplier),
                Int(green * multiplier),
                Int(blue * multiplier),
                alpha
                //Int(alpha * multiplier)
            )
        }
    }
    
}