抛光扩展从原来的答案@Tom 请随意在这里更新代码

extension UIColor{
    convenience init (hexString:String) {
        var cleanString:String = hexString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString

        if (cleanString.hasPrefix("#")) {
            cleanString = cleanString.substringFromIndex(cleanString.startIndex.advancedBy(1))
        }

        if (cleanString.characters.count != 6) {
            self.init()
        }
        else{
            var rgbValue = UInt32()
            let scanner = NSScanner(string: cleanString)
            scanner.scanHexInt(&rgbValue)

            self.init(
                red: CGFloat((rgbValue & 0xFF0000) >> 16)/255.0,
                green: CGFloat((rgbValue & 0xFF00) >> 8)/255.0,
                blue: CGFloat(rgbValue & 0xFF)/255.0,
                alpha: 1.0)
        }
    }
}

这是另一种选择。

- (UIColor *)colorWithRGBHex:(UInt32)hex
{
    int r = (hex >> 16) & 0xFF;
    int g = (hex >> 8) & 0xFF;
    int b = (hex) & 0xFF;

    return [UIColor colorWithRed:r / 255.0f
                           green:g / 255.0f
                            blue:b / 255.0f
                           alpha:1.0f];
}

使用Xcode的原生颜色文字功能来轻松地添加十六进制颜色。

在你的代码中输入颜色文字，然后让Xcode自动完成剩下的工作。

颜色选择界面将允许你粘贴十六进制颜色:#FF9300

宏的git差异将显示RGB值而不是十六进制值:

let orange = #colorLiteral(red: 1, green: 0.5763723254, blue: 0, alpha: 1)

但它仍然是一种简单的方法来粘贴十六进制没有任何第三方工具或扩展。

我已经找到了一个与Android使用的十六进制格式字符串100%兼容的解决方案，我发现这在进行跨平台移动开发时非常有用。它让我在两个平台上都使用一种颜色。您可以在没有归属的情况下随意重用，如果您愿意，也可以在Apache许可下重用。

#import "UIColor+HexString.h"

@interface UIColor(HexString)

+ (UIColor *) colorWithHexString: (NSString *) hexString;
+ (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length;

@end


@implementation UIColor(HexString)

+ (UIColor *) colorWithHexString: (NSString *) hexString {
    NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];
    CGFloat alpha, red, blue, green;
    switch ([colorString length]) {
        case 3: // #RGB
            alpha = 1.0f;
            red   = [self colorComponentFrom: colorString start: 0 length: 1];
            green = [self colorComponentFrom: colorString start: 1 length: 1];
            blue  = [self colorComponentFrom: colorString start: 2 length: 1];
            break;
        case 4: // #ARGB
            alpha = [self colorComponentFrom: colorString start: 0 length: 1];
            red   = [self colorComponentFrom: colorString start: 1 length: 1];
            green = [self colorComponentFrom: colorString start: 2 length: 1];
            blue  = [self colorComponentFrom: colorString start: 3 length: 1];          
            break;
        case 6: // #RRGGBB
            alpha = 1.0f;
            red   = [self colorComponentFrom: colorString start: 0 length: 2];
            green = [self colorComponentFrom: colorString start: 2 length: 2];
            blue  = [self colorComponentFrom: colorString start: 4 length: 2];                      
            break;
        case 8: // #AARRGGBB
            alpha = [self colorComponentFrom: colorString start: 0 length: 2];
            red   = [self colorComponentFrom: colorString start: 2 length: 2];
            green = [self colorComponentFrom: colorString start: 4 length: 2];
            blue  = [self colorComponentFrom: colorString start: 6 length: 2];                      
            break;
        default:
            [NSException raise:@"Invalid color value" format: @"Color value %@ is invalid.  It should be a hex value of the form #RBG, #ARGB, #RRGGBB, or #AARRGGBB", hexString];
            break;
    }
    return [UIColor colorWithRed: red green: green blue: blue alpha: alpha];
}

+ (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length {
    NSString *substring = [string substringWithRange: NSMakeRange(start, length)];
    NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];
    unsigned hexComponent;
    [[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];
    return hexComponent / 255.0;
}

@end 

迅速:

extension UIColor {
    convenience init?(hexString: String?) {
        let input: String! = (hexString ?? "")
            .replacingOccurrences(of: "#", with: "")
            .uppercased()
        var alpha: CGFloat = 1.0
        var red: CGFloat = 0
        var blue: CGFloat = 0
        var green: CGFloat = 0
        switch (input.count) {
        case 3 /* #RGB */:
            red = Self.colorComponent(from: input, start: 0, length: 1)
            green = Self.colorComponent(from: input, start: 1, length: 1)
            blue = Self.colorComponent(from: input, start: 2, length: 1)
            break
        case 4 /* #ARGB */:
            alpha = Self.colorComponent(from: input, start: 0, length: 1)
            red = Self.colorComponent(from: input, start: 1, length: 1)
            green = Self.colorComponent(from: input, start: 2, length: 1)
            blue = Self.colorComponent(from: input, start: 3, length: 1)
            break
        case 6 /* #RRGGBB */:
            red = Self.colorComponent(from: input, start: 0, length: 2)
            green = Self.colorComponent(from: input, start: 2, length: 2)
            blue = Self.colorComponent(from: input, start: 4, length: 2)
            break
        case 8 /* #AARRGGBB */:
            alpha = Self.colorComponent(from: input, start: 0, length: 2)
            red = Self.colorComponent(from: input, start: 2, length: 2)
            green = Self.colorComponent(from: input, start: 4, length: 2)
            blue = Self.colorComponent(from: input, start: 6, length: 2)
            break
        default:
            NSException.raise(NSExceptionName("Invalid color value"), format: "Color value \"%@\" is invalid.  It should be a hex value of the form #RBG, #ARGB, #RRGGBB, or #AARRGGBB", arguments:getVaList([hexString ?? ""]))
        }
        self.init(red: red, green: green, blue: blue, alpha: alpha)
    }
    
    static func colorComponent(from string: String!, start: Int, length: Int) -> CGFloat {
        let substring = (string as NSString)
            .substring(with: NSRange(location: start, length: length))
        let fullHex = length == 2 ? substring : "\(substring)\(substring)"
        var hexComponent: UInt64 = 0
        Scanner(string: fullHex)
            .scanHexInt64(&hexComponent)
        return CGFloat(Double(hexComponent) / 255.0)
    }
}

Swift 2.0 - Xcode 7.2

为UIColor添加扩展。

文件-新建- Swift文件-命名。添加以下内容。

extension UIColor {
    convenience init(hexString:String) {
        let hexString:NSString = hexString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
        let scanner            = NSScanner(string: hexString as String)
        if (hexString.hasPrefix("#")) {
            scanner.scanLocation = 1
        }

        var color:UInt32 = 0
        scanner.scanHexInt(&color)

        let mask = 0x000000FF
        let r = Int(color >> 16) & mask
        let g = Int(color >> 8) & mask
        let b = Int(color) & mask

        let red   = CGFloat(r) / 255.0
        let green = CGFloat(g) / 255.0
        let blue  = CGFloat(b) / 255.0
        self.init(red:red, green:green, blue:blue, alpha:1)
    }

    func toHexString() -> String {
        var r:CGFloat = 0
        var g:CGFloat = 0
        var b:CGFloat = 0
        var a:CGFloat = 0
        getRed(&r, green: &g, blue: &b, alpha: &a)
        let rgb:Int = (Int)(r*255)<<16 | (Int)(g*255)<<8 | (Int)(b*255)<<0
        return NSString(format:"#%06x", rgb) as String
    }        
}

用法:

Ex. Setting Button's color from hexCode.
    override func viewWillAppear(animated: Bool) {
        loginButton.tintColor = UIColor(hexString: " hex code here ")
}

Ex. Converting Button's current color to hex Code.

    override func viewWillAppear(animated: Bool) {
        let hexString = loginButton.tintColor.toHexString()
        print("HEX STRING: \(hexString)")

    }

除了颜色，我还喜欢保证alpha，所以我自己写类别

+ (UIColor *) colorWithHex:(int)color {

    float red = (color & 0xff000000) >> 24;
    float green = (color & 0x00ff0000) >> 16;
    float blue = (color & 0x0000ff00) >> 8;
    float alpha = (color & 0x000000ff);

    return [UIColor colorWithRed:red/255.0 green:green/255.0 blue:blue/255.0 alpha:alpha/255.0];
}

像这样很容易使用

[UIColor colorWithHex:0xFF0000FF]; //Red
[UIColor colorWithHex:0x00FF00FF]; //Green
[UIColor colorWithHex:0x00FF00FF]; //Blue
[UIColor colorWithHex:0x0000007F]; //transparent black