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)]

一个简明的解决方案:

// Assumes input like "#00FF00" (#RRGGBB).
+ (UIColor *)colorFromHexString:(NSString *)hexString {
    unsigned rgbValue = 0;
    NSScanner *scanner = [NSScanner scannerWithString:hexString];
    [scanner setScanLocation:1]; // bypass '#' character
    [scanner scanHexInt:&rgbValue];
    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
}

Swift 2.0版本的解决方案，将处理alpha值的颜色和完美的错误处理:

func RGBColor(hexColorStr : String) -> UIColor?{

    var red:CGFloat = 0.0
    var green:CGFloat = 0.0
    var blue:CGFloat = 0.0
    var alpha:CGFloat = 1.0

    if hexColorStr.hasPrefix("#"){

        let index   = hexColorStr.startIndex.advancedBy(1)
        let hex     = hexColorStr.substringFromIndex(index)
        let scanner = NSScanner(string: hex)
        var hexValue: CUnsignedLongLong = 0

        if scanner.scanHexLongLong(&hexValue)
        {
            if hex.characters.count == 6
            {
                red   = CGFloat((hexValue & 0xFF0000) >> 16) / 255.0
                green = CGFloat((hexValue & 0x00FF00) >> 8)  / 255.0
                blue  = CGFloat(hexValue & 0x0000FF) / 255.0
            }
            else if hex.characters.count == 8
            {
                red   = CGFloat((hexValue & 0xFF000000) >> 24) / 255.0
                green = CGFloat((hexValue & 0x00FF0000) >> 16) / 255.0
                blue  = CGFloat((hexValue & 0x0000FF00) >> 8)  / 255.0
                alpha = CGFloat(hexValue & 0x000000FF)         / 255.0
            }
            else
            {
                print("invalid hex code string, length should be 7 or 9", terminator: "")
                return nil
            }
        }
        else
        {
            print("scan hex error")
       return nil
        }
    }

    let color: UIColor =  UIColor(red:CGFloat(red), green: CGFloat(green), blue:CGFloat(blue), alpha: alpha)
    return color
}

我找到了一个很好的UIColor类别，UIColor+PXExtensions。

用法:UIColor *mycolor = [UIColor pxColorWithHexValue:@"#BADA55"];

而且，为了防止链接到我的要点失败，这里是实际的实现代码:

//
//  UIColor+PXExtensions.m
//

#import "UIColor+UIColor_PXExtensions.h"

@implementation UIColor (UIColor_PXExtensions)

+ (UIColor*)pxColorWithHexValue:(NSString*)hexValue
{
    //Default
    UIColor *defaultResult = [UIColor blackColor];

    //Strip prefixed # hash
    if ([hexValue hasPrefix:@"#"] && [hexValue length] > 1) {
        hexValue = [hexValue substringFromIndex:1];
    }

    //Determine if 3 or 6 digits
    NSUInteger componentLength = 0;
    if ([hexValue length] == 3)
    {
        componentLength = 1;
    }
    else if ([hexValue length] == 6)
    {
        componentLength = 2;
    }
    else
    {
        return defaultResult;
    }

    BOOL isValid = YES;
    CGFloat components[3];

    //Seperate the R,G,B values
    for (NSUInteger i = 0; i < 3; i++) {
        NSString *component = [hexValue substringWithRange:NSMakeRange(componentLength * i, componentLength)];
        if (componentLength == 1) {
            component = [component stringByAppendingString:component];
        }
        NSScanner *scanner = [NSScanner scannerWithString:component];
        unsigned int value;
        isValid &= [scanner scanHexInt:&value];
        components[i] = (CGFloat)value / 256.0f;
    }

    if (!isValid) {
        return defaultResult;
    }

    return [UIColor colorWithRed:components[0]
                           green:components[1]
                            blue:components[2]
                           alpha:1.0];
}

@end

有cocoapod支持，这很好

https://github.com/mRs-/HexColors

// with hash
NSColor *colorWithHex = [NSColor colorWithHexString:@"#ff8942" alpha:1];

// wihtout hash
NSColor *secondColorWithHex = [NSColor colorWithHexString:@"ff8942" alpha:1];

// short handling
NSColor *shortColorWithHex = [NSColor colorWithHexString:@"fff" alpha:1]

你可以使用这个库

https://github.com/burhanuddin353/TFTColor

斯威夫特

UIColor.colorWithRGB(hexString: "FF34AE" alpha: 1.0)

objective - c

[UIColor colorWithRGBHexString:@"FF34AE" alpha:1.0f]