斯威夫特4.0

使用这种单行方法

override func viewDidLoad() {
    super.viewDidLoad()

   let color = UIColor(hexColor: "FF00A0")
   self.view.backgroundColor = color

}

你必须创建新的类或使用任何控制器，你需要使用十六进制颜色。这个扩展类为您提供UIColor，将十六进制转换为RGB颜色。

extension UIColor {
convenience init(hexColor: String) {
    let scannHex = Scanner(string: hexColor)
    var rgbValue: UInt64 = 0
    scannHex.scanLocation = 0
    scannHex.scanHexInt64(&rgbValue)
    let r = (rgbValue & 0xff0000) >> 16
    let g = (rgbValue & 0xff00) >> 8
    let b = rgbValue & 0xff
    self.init(
        red: CGFloat(r) / 0xff,
        green: CGFloat(g) / 0xff,
        blue: CGFloat(b) / 0xff, alpha: 1
    )
  }
}

这个答案展示了如何在Obj-C中实现。这座桥是要用的

let rgbValue = 0xFFEEDD
let r = Float((rgbValue & 0xFF0000) >> 16)/255.0
let g = Float((rgbValue & 0xFF00) >> 8)/255.0
let b = Float((rgbValue & 0xFF))/255.0
self.backgroundColor = UIColor(red:r, green: g, blue: b, alpha: 1.0)

Swift 5 (Swift 4, Swift 3) UIColor扩展:

extension UIColor {
    convenience init(hexString: String) {
        let hex = hexString.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
        var int = UInt64()
        Scanner(string: hex).scanHexInt64(&int)
        let a, r, g, b: UInt64
        switch hex.count {
        case 3: // RGB (12-bit)
            (a, r, g, b) = (255, (int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
        case 6: // RGB (24-bit)
            (a, r, g, b) = (255, int >> 16, int >> 8 & 0xFF, int & 0xFF)
        case 8: // ARGB (32-bit)
            (a, r, g, b) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
        default:
            (a, r, g, b) = (255, 0, 0, 0)
        }
        self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
    }
}

用法:

let darkGrey = UIColor(hexString: "#757575")

斯威夫特2。x版本:

extension UIColor {
    convenience init(hexString: String) {
        let hex = hexString.stringByTrimmingCharactersInSet(NSCharacterSet.alphanumericCharacterSet().invertedSet)
        var int = UInt32()
        NSScanner(string: hex).scanHexInt(&int)
        let a, r, g, b: UInt32
        switch hex.characters.count {
        case 3: // RGB (12-bit)
            (a, r, g, b) = (255, (int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
        case 6: // RGB (24-bit)
            (a, r, g, b) = (255, int >> 16, int >> 8 & 0xFF, int & 0xFF)
        case 8: // ARGB (32-bit)
            (a, r, g, b) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
        default:
            (a, r, g, b) = (255, 0, 0, 0)
        }
        self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
    }
}

Xcode 13.2.1, M1, Swift 5.5

我们可以在ColorLiterals中使用Hex

输入#colorLiteral(在Xcode中，这将触发并修复与ColorLiterals相关的错误

然后点击其他

然后选择RGB滑块，你现在可以看到十六进制面板

iOS 14, SwiftUI 2.0, swift 5.1, Xcode beta12

extension Color {
  static func hexColour(hexValue:UInt32)->Color
    {
      let red = Double((hexValue & 0xFF0000) >> 16) / 255.0
      let green = Double((hexValue & 0xFF00) >> 8) / 255.0
      let blue = Double(hexValue & 0xFF) / 255.0
      return Color(red:red, green:green, blue:blue)
    }
}

用十六进制数表示

let red = Color.hexColour(hexValue: 0xFF0000)

public static func hexStringToUIColor (hex:String) -> UIColor {
    var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

    if (cString.hasPrefix("#")) {
        cString.remove(at: cString.startIndex)
    }

    if ((cString.characters.count) == 6) {

        var rgbValue:UInt32 = 0
        Scanner(string: cString).scanHexInt32(&rgbValue)

        return UIColor(
            red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
            green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
            blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
            alpha: CGFloat(1.0)
        )
    }else if ((cString.characters.count) == 8) {

        var rgbValue:UInt32 = 0
        Scanner(string: cString).scanHexInt32(&rgbValue)

        return UIColor(
            red: CGFloat((rgbValue & 0x00FF0000) >> 16) / 255.0,
            green: CGFloat((rgbValue & 0x0000FF00) >> 8) / 255.0,
            blue: CGFloat(rgbValue & 0x000000FF) / 255.0,
            alpha: CGFloat((rgbValue & 0xFF000000) >> 24) / 255.0
        )
    }else{
        return UIColor.gray
    }
}

如何使用

var color: UIColor = hexStringToUIColor(hex: "#00ff00"); // Without transparency
var colorWithTransparency: UIColor = hexStringToUIColor(hex: "#dd00ff00"); // With transparency