另一种方法

斯威夫特3.0

为UIColor写一个扩展

// To change the HexaDecimal value to Corresponding Color
extension UIColor
{
    class func uicolorFromHex(_ rgbValue:UInt32, alpha : CGFloat)->UIColor

    {
        let red = CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0
        let green = CGFloat((rgbValue & 0xFF00) >> 8) / 255.0
        let blue = CGFloat(rgbValue & 0xFF) / 255.0
        return UIColor(red:red, green:green, blue:blue, alpha: alpha)
    }
}

你可以像这样用hex直接创建UIColor

let carrot = UIColor.uicolorFromHex(0xe67e22, alpha: 1))

RGBA版本Swift 3/4

我喜欢卢卡的回答，因为我认为它是最优雅的。

然而，我不希望我的颜色指定在ARGB。我宁愿RGBA +，我也需要在处理字符串的情况下，为每个频道指定1个字符“#FFFA”。

这个版本还增加了错误抛出+剥离'#'字符如果它包含在字符串中。 这是我修改后的Swift表格。

public enum ColourParsingError: Error
{
    
    case invalidInput(String)
}
extension UIColor {
    public convenience init(hexString: String) throws
    {
        let hexString = hexString.replacingOccurrences(of: "#", with: "")
        let hex = hexString.trimmingCharacters(in:NSCharacterSet.alphanumerics.inverted)
        var int = UInt32()
        Scanner(string: hex).scanHexInt32(&int)
        let a, r, g, b: UInt32
        switch hex.count 
        {
        case 3: // RGB (12-bit)
            (r, g, b,a) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17,255)
        //iCSS specification in the form of #F0FA
        case 4: // RGB (24-bit)
            (r, g, b,a) = ((int >> 12) * 17, (int >> 8 & 0xF) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
        case 6: // RGB (24-bit)
            (r, g, b, a) = (int >> 16, int >> 8 & 0xFF, int & 0xFF,255)
        case 8: // ARGB (32-bit)
            (r, g, b, a) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
        default:
            throw ColourParsingError.invalidInput("String is not a valid hex colour string: \(hexString)")
        }
        self.init(red: CGFloat(r) / 255, green: CGFloat(g) / 255, blue: CGFloat(b) / 255, alpha: CGFloat(a) / 255)
    }
}

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

只是对第一个答案的一些补充

(还没有检查alpha，可能需要添加一个if next > 0xffffff):

extension UIColor {

struct COLORS_HEX {
    static let Primary = 0xffffff
    static let PrimaryDark = 0x000000
    static let Accent = 0xe89549
    static let AccentDark = 0xe27b2a
    static let TextWhiteSemiTransparent = 0x80ffffff
}

convenience init(red: Int, green: Int, blue: Int, alphaH: Int) {
    assert(red >= 0 && red <= 255, "Invalid red component")
    assert(green >= 0 && green <= 255, "Invalid green component")
    assert(blue >= 0 && blue <= 255, "Invalid blue component")
    assert(alphaH >= 0 && alphaH <= 255, "Invalid alpha component")

    self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: CGFloat(alphaH) / 255.0)
}

convenience init(netHex:Int) {
    self.init(red:(netHex >> 16) & 0xff, green:(netHex >> 8) & 0xff, blue:netHex & 0xff, alphaH: (netHex >> 24) & 0xff)
}

}

支持7十六进制颜色类型

有7种十六进制颜色格式:""#FF0000"，"0xFF0000"， "FF0000"， "F00"， "red"， 0x00FF00, 16711935

NSColorParser.nsColor("#FF0000",1)//red nsColor
NSColorParser.nsColor("FF0",1)//red nsColor
NSColorParser.nsColor("0xFF0000",1)//red nsColor
NSColorParser.nsColor("#FF0000",1)//red nsColor
NSColorParser.nsColor("FF0000",1)//red nsColor
NSColorParser.nsColor(0xFF0000,1)//red nsColor
NSColorParser.nsColor(16711935,1)//red nsColor

注意:这不是一个“单文件解决方案”，有一些依赖关系，但查找它们可能比从头开始研究更快。

https://github.com/eonist/swift-utils/blob/2882002682c4d2a3dc7cb3045c45f66ed59d566d/geom/color/NSColorParser.swift

永久链接: https://github.com/eonist/Element/wiki/Progress#supporting-7-hex-color-types

Swift 5.3 & SwiftUI:通过UIColor支持十六进制和CSS颜色名称

依据代码

斯威夫特包

SwiftUI包

字符串的例子:

橙子、酸橙、番茄等。 Clear, Transparent, nil和空字符串产生[UIColor clearColor] 美国广播公司 abc7 # abc7 00飞行符 # 00飞行符 00 ffff77

操场上的输出: