另一个带有alpha的版本

#define UIColorFromRGBA(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF000000) >> 24))/255.0 green:((float)((rgbValue & 0xFF0000) >> 16))/255.0 blue:((float)((rgbValue & 0xFF00) >> 8 ))/255.0 alpha:((float)((rgbValue & 0xFF))/255.0)]

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

extension UIColor 
{
    class func fromHexaString(hex:String) -> UIColor
    {
        let scanner           = Scanner(string: hex)
        scanner.scanLocation  = 0
        var rgbValue: UInt64  = 0
        scanner.scanHexInt64(&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)
        )
    }
}

//you can call like this.

UIColor.fromHexaString(hex:3276b1)

您可以使用各种在线工具将HEX字符串转换为实际的UIColor。查看uicolor.org或UI颜色选择器。输出将被转换为Objective-C代码，如下所示:

[UIColor colorWithRed:0.93 green:0.80 blue:0.80 alpha:1.0];

可以嵌入到应用程序中。希望这能有所帮助!

另一个实现允许字符串“FFF”或“FFFFFF”，并使用alpha:

+ (UIColor *) colorFromHexString:(NSString *)hexString alpha: (CGFloat)alpha{
    NSString *cleanString = [hexString stringByReplacingOccurrencesOfString:@"#" withString:@""];
    if([cleanString length] == 3) {
        cleanString = [NSString stringWithFormat:@"%@%@%@%@%@%@",
                       [cleanString substringWithRange:NSMakeRange(0, 1)],[cleanString substringWithRange:NSMakeRange(0, 1)],
                       [cleanString substringWithRange:NSMakeRange(1, 1)],[cleanString substringWithRange:NSMakeRange(1, 1)],
                       [cleanString substringWithRange:NSMakeRange(2, 1)],[cleanString substringWithRange:NSMakeRange(2, 1)]];
    }
    if([cleanString length] == 6) {
        cleanString = [cleanString stringByAppendingString:@"ff"];
    }

    unsigned int baseValue;
    [[NSScanner scannerWithString:cleanString] scanHexInt:&baseValue];

    float red = ((baseValue >> 24) & 0xFF)/255.0f;
    float green = ((baseValue >> 16) & 0xFF)/255.0f;
    float blue = ((baseValue >> 8) & 0xFF)/255.0f;

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

为UIColor创建优雅的扩展:

extension UIColor {

convenience init(string: String) {

        var uppercasedString = string.uppercased()
        uppercasedString.remove(at: string.startIndex)

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

        let red = CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0
        let green = CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0
        let blue = CGFloat(rgbValue & 0x0000FF) / 255.0

        self.init(red: red, green: green, blue: blue, alpha: 1)
    }
}

创建红色:

let red = UIColor(string: "#ff0000")