swift 4.0利用Scanner根据十六进制颜色创建UIColor
首先创建一个UIColor的extension类
/// 用十六进制颜色创建UIColor
/// - Parameter hexColor: 十六进制颜色 (0F0F0F)
convenience init(hexColor: String) {
// 存储转换后的数值
var red:UInt32 = 0, green:UInt32 = 0, blue:UInt32 = 0
// 分别转换进行转换
var currentHexColor:String = hexColor
if hexColor.hasPrefix("#") { //截取字符串 去调#号
let index = currentHexColor.index(currentHexColor.startIndex, offsetBy: 1)
currentHexColor = String(currentHexColor[index...])
}
if currentHexColor.count >= 8 {
var alpha:UInt32 = 0
Scanner(string: currentHexColor[0..<2]).scanHexInt32(&alpha)
Scanner(string: currentHexColor[2..<4]).scanHexInt32(&red)
Scanner(string: currentHexColor[4..<6]).scanHexInt32(&green)
Scanner(string: currentHexColor[6..<8]).scanHexInt32(&blue)
self.init(red: CGFloat(red)/255.0, green: CGFloat(green)/255.0, blue: CGFloat(blue)/255.0, alpha: CGFloat(alpha)/255.0)
return
}
Scanner(string: currentHexColor[0..<2]).scanHexInt32(&red)
Scanner(string: currentHexColor[2..<4]).scanHexInt32(&green)
Scanner(string: currentHexColor[4..<6]).scanHexInt32(&blue)
self.init(red: CGFloat(red)/255.0, green: CGFloat(green)/255.0, blue: CGFloat(blue)/255.0, alpha: 1.0)
}
