斯威夫特2.0

下面的代码是在xcode 7.2上测试的

import UIKit
extension UIColor{

    public convenience init?(colorCodeInHex: String, alpha: Float = 1.0){

        var filterColorCode:String =  colorCodeInHex.stringByReplacingOccurrencesOfString("#", withString: "")

        if  filterColorCode.characters.count != 6 {
            self.init(red: 0.0, green: 0.0, blue: 0.0, alpha: CGFloat(alpha))
            return
        }

        filterColorCode = filterColorCode.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString

        var range = Range(start: filterColorCode.startIndex.advancedBy(0), end: filterColorCode.startIndex.advancedBy(2))
        let rString = filterColorCode.substringWithRange(range)

        range = Range(start: filterColorCode.startIndex.advancedBy(2), end: filterColorCode.startIndex.advancedBy(4))
        let gString = filterColorCode.substringWithRange(range)


        range = Range(start: filterColorCode.startIndex.advancedBy(4), end: filterColorCode.startIndex.advancedBy(6))
        let bString = filterColorCode.substringWithRange(range)

        var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0;
        NSScanner(string: rString).scanHexInt(&r)
        NSScanner(string: gString).scanHexInt(&g)
        NSScanner(string: bString).scanHexInt(&b)


        self.init(red: CGFloat(r) / 255.0, green: CGFloat(g) / 255.0, blue: CGFloat(b) / 255.0, alpha: CGFloat(alpha))
        return
    }
}

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
    )
  }
}

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))

斯威夫特2.3: 用户界面颜色扩展。我认为这样更简单。

extension UIColor {
    static func colorFromHex(hexString: String, alpha: CGFloat = 1) -> UIColor {
        //checking if hex has 7 characters or not including '#'
        if hexString.characters.count < 7 {
            return UIColor.whiteColor()
        }
        //string by removing hash
        let hexStringWithoutHash = hexString.substringFromIndex(hexString.startIndex.advancedBy(1))

        //I am extracting three parts of hex color Red (first 2 characters), Green (middle 2 characters), Blue (last two characters)
        let eachColor = [
            hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex...hexStringWithoutHash.startIndex.advancedBy(1)),
            hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex.advancedBy(2)...hexStringWithoutHash.startIndex.advancedBy(3)),
            hexStringWithoutHash.substringWithRange(hexStringWithoutHash.startIndex.advancedBy(4)...hexStringWithoutHash.startIndex.advancedBy(5))]

        let hexForEach = eachColor.map {CGFloat(Int($0, radix: 16) ?? 0)} //radix is base of numeric system you want to convert to, Hexadecimal has base 16

        //return the color by making color
        return UIColor(red: hexForEach[0] / 255, green: hexForEach[1] / 255, blue: hexForEach[2] / 255, alpha: alpha)
    }
}

用法:

let color = UIColor.colorFromHex("#25ac09")

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

斯威夫特5.0

你不能在Swift中直接使用#ffffff语法。以下是我用于网络相关项目的代码。支持alpha和三位数字。

用法示例(大写值也可以):

    let hex = "#FADE2B"  // yellow
    let color = NSColor(fromHex: hex)

支持的字符串格式:

"fff" // RGB "#fff" // #RGB "ffff" // RGBA "#ffff" // #RGBA . "ffffff" // RRGGBB . "#ffffff" // #RRGGBB . "ffffffff" // RRGGBBAA . "#ffffffff" // #RRGGBBAA .

数字代表红色，绿色，蓝色和阿尔法(像透明度)。对于iOS，用UIColor替换NSColor。

代码:

    extension NSColor {
        /// Initialises NSColor from a hexadecimal string. Color is clear if string is invalid.
        /// - Parameter fromHex: supported formats are "#RGB", "#RGBA", "#RRGGBB", "#RRGGBBAA", with or without the # character
        public convenience init(fromHex:String) {
            var r = 0, g = 0, b = 0, a = 255
            let offset = fromHex.hasPrefix("#") ? 1 : 0
            let ch = fromHex.map{$0}
            switch(ch.count - offset) {
            case 8:
                a = 16 * (ch[offset+6].hexDigitValue ?? 0) + (ch[offset+7].hexDigitValue ?? 0)
                fallthrough
            case 6:
                r = 16 * (ch[offset+0].hexDigitValue ?? 0) + (ch[offset+1].hexDigitValue ?? 0)
                g = 16 * (ch[offset+2].hexDigitValue ?? 0) + (ch[offset+3].hexDigitValue ?? 0)
                b = 16 * (ch[offset+4].hexDigitValue ?? 0) + (ch[offset+5].hexDigitValue ?? 0)
                break
            case 4:
                a = 16 * (ch[offset+3].hexDigitValue ?? 0) + (ch[offset+3].hexDigitValue ?? 0)
                fallthrough
            case 3:  // Three digit #0D3 is the same as six digit #00DD33
                r = 16 * (ch[offset+0].hexDigitValue ?? 0) + (ch[offset+0].hexDigitValue ?? 0)
                g = 16 * (ch[offset+1].hexDigitValue ?? 0) + (ch[offset+1].hexDigitValue ?? 0)
                b = 16 * (ch[offset+2].hexDigitValue ?? 0) + (ch[offset+2].hexDigitValue ?? 0)
                break
            default:
                a = 0
                break
            }
            self.init(red: CGFloat(r)/255, green: CGFloat(g)/255, blue: CGFloat(b)/255, alpha: CGFloat(a)/255)
            
        }
    }
    // Author: Andrew Kingdom

授权:CC BY

我发现这比下面的复制/粘贴更整洁

选择:

您可以删除#并将其存储为32位无符号整数字面量，由0x前缀表示，即0xffffff。不过，你仍然需要代码将其转换为颜色。

如果你想要一种非编程的方式来获取颜色:打开一个颜色选择器对话框，切换到colour Sliders > RGB Sliders，并将值粘贴/输入到“Hex color #”框中。(不要粘贴#散列符号。)