试试这个:这段代码将从十六进制颜色字符串返回UIColor

- (UIColor*)colorWithHexString:(NSString*)hex  
{  
    NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];  

    // String should be 6 or 8 characters  
    if ([cString length] < 6) return [UIColor grayColor];  

    // strip 0X if it appears  
    if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];  

    if ([cString length] != 6) return  [UIColor grayColor];  

    // Separate into r, g, b substrings  
    NSRange range;  
    range.location = 0;  
    range.length = 2;  
    NSString *rString = [cString substringWithRange:range];  

    range.location = 2;  
    NSString *gString = [cString substringWithRange:range];  

    range.location = 4;  
    NSString *bString = [cString substringWithRange:range];  

    // Scan values  
    unsigned int r, g, b;  
    [[NSScanner scannerWithString:rString] scanHexInt:&r];  
    [[NSScanner scannerWithString:gString] scanHexInt:&g];  
    [[NSScanner scannerWithString:bString] scanHexInt:&b];  

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

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

大多数发布的解决方案使用了Scanner，但至少在现代Swift中你并不真正需要它。相反，你可以简单地使用UInt init和基数16，然后使用基本的二进制操作来获得UIColor组件:

func stringToColor(color: String) -> UIColor {
    guard let i = UInt(color, radix: 16) else {
        return UIColor.white
    }
    return UIColor(
        red: CGFloat((i & 0xFF0000) >> 16) / 255.0,
        green: CGFloat((i & 0xFF00) >> 8) / 255.0,
        blue: CGFloat(i & 0xFF) / 255.0,
        alpha: 1.0
    )
}

这个解决方案期望输入像“FF00FF”，你可能需要删除前面的哈希符号(#)，如果你的字符串中有一个。

    //UIColorWithHexString

    static UIColor * UIColorWithHexString(NSString *hex) {
        unsigned int rgb = 0;
        [[NSScanner scannerWithString:
          [[hex uppercaseString] stringByTrimmingCharactersInSet:
           [[NSCharacterSet characterSetWithCharactersInString:@"0123456789ABCDEF"] invertedSet]]]
         scanHexInt:&rgb];
        return [UIColor colorWithRed:((CGFloat)((rgb & 0xFF0000) >> 16)) / 255.0
                               green:((CGFloat)((rgb & 0xFF00) >> 8)) / 255.0
                                blue:((CGFloat)(rgb & 0xFF)) / 255.0
                               alpha:1.0];
    }

使用

self.view.backgroundColor = UIColorWithHexString(@"#0F35C0");

有一个很好的帖子是关于如何解决OP的问题，从十六进制字符串中提取UIColor。下面给出的解决方案与其他解决方案不同，因为它支持字符串值，可能包括'0x'或'#'前缀的十六进制字符串表示…(请参阅使用)

这是主要的部分…

- (UIColor *)getUIColorObjectFromHexString:(NSString *)hexStr alpha:(CGFloat)alpha
{
  // Convert hex string to an integer
  unsigned int hexint = [self intFromHexString:hexStr];
 
  // Create a color object, specifying alpha as well
  UIColor *color =
    [UIColor colorWithRed:((CGFloat) ((hexint & 0xFF0000) >> 16))/255
    green:((CGFloat) ((hexint & 0xFF00) >> 8))/255
    blue:((CGFloat) (hexint & 0xFF))/255
    alpha:alpha];
 
  return color;
}

助手方法……

- (unsigned int)intFromHexString:(NSString *)hexStr
{
  unsigned int hexInt = 0;
 
  // Create scanner
  NSScanner *scanner = [NSScanner scannerWithString:hexStr];
 
  // Tell scanner to skip the # character
  [scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"#"]];
 
  // Scan hex value
  [scanner scanHexInt:&hexInt];
 
  return hexInt;
}

用法:

NSString *hexStr1 = @"123ABC";
NSString *hexStr2 = @"#123ABC";
NSString *hexStr3 = @"0x123ABC";

UIColor *color1 = [self getUIColorObjectFromHexString:hexStr1 alpha:.9];
NSLog(@"UIColor: %@", color1);
 
UIColor *color2 = [self getUIColorObjectFromHexString:hexStr2 alpha:.9];
NSLog(@"UIColor: %@", color2);
 
UIColor *color3 = [self getUIColorObjectFromHexString:hexStr3 alpha:.9];
NSLog(@"UIColor: %@", color3);

完整的参考文章

Swift 2 +

我已经将这个解决方案移植到Swift 2.2。注意，我已经将alpha参数更改为使用默认设置为1.0。我还根据Swift 2.2中的NSScanner类的要求将int类型更新为UInt32。

func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {
    
    // Convert hex string to an integer
    let hexint = Int(self.intFromHexString(hexString))
    let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
    let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
    let blue = CGFloat((hexint & 0xff) >> 0) / 255.0 
    
    // Create color object, specifying alpha as well
    let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    return color
}

func intFromHexString(hexStr: String) -> UInt32 {
    var hexInt: UInt32 = 0
    // Create scanner
    let scanner: NSScanner = NSScanner(string: hexStr)
    // Tell scanner to skip the # character
    scanner.charactersToBeSkipped = NSCharacterSet(charactersInString: "#")
    // Scan hex value
    scanner.scanHexInt(&hexInt)
    return hexInt
}

斯威夫特 4+

采用与swift 4相同的变化逻辑，

func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {
    
    // Convert hex string to an integer
    let hexint = Int(self.intFromHexString(hexStr: hexString))
    let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
    let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
    let blue = CGFloat((hexint & 0xff) >> 0) / 255.0
    
    // Create color object, specifying alpha as well
    let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
    return color
}

func intFromHexString(hexStr: String) -> UInt32 {
    var hexInt: UInt32 = 0
    // Create scanner
    let scanner: Scanner = Scanner(string: hexStr)
    // Tell scanner to skip the # character
    scanner.charactersToBeSkipped = CharacterSet(charactersIn: "#")
    // Scan hex value
    scanner.scanHexInt32(&hexInt)
    return hexInt
}

Swift 5 (iOS 13)+

下面显示了在SDK弃用scanHexInt32的情况下工作的更新。我将代码封装到Swift playground文件中。

//: A UIKit based Playground for presenting user interface
  
import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    override func loadView() {
        let view = UIView()
        view.backgroundColor = .white

        let label = UILabel()
        label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
        label.text = "Hello World!"
        label.textColor = colorWithHexString(hexString: "22F728")
        
        view.addSubview(label)
        self.view = view
    }
    
    func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {

        // Convert hex string to an integer
        let hexint = Int(self.intFromHexString(hexStr: hexString))
        let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
        let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
        let blue = CGFloat((hexint & 0xff) >> 0) / 255.0

        // Create color object, specifying alpha as well
        let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
        return color
    }

    func intFromHexString(hexStr: String) -> UInt32 {
        var hexInt: UInt32 = 0
        // Create scanner
        let scanner: Scanner = Scanner(string: hexStr)
        // Tell scanner to skip the # character
        scanner.charactersToBeSkipped = CharacterSet(charactersIn: "#")
        // Scan hex value
        hexInt = UInt32(bitPattern: scanner.scanInt32(representation: .hexadecimal) ?? 0)
        return hexInt
    }
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()

彩色十六进制参考 HTML颜色名称和代码 十六进制颜色编码

斯威夫特的版本。作为函数或扩展使用。

Function

  func UIColorFromRGB(colorCode: String, alpha: Float = 1.0) -> UIColor{
    var scanner = NSScanner(string:colorCode)
    var color:UInt32 = 0;
    scanner.scanHexInt(&color)
    
    let mask = 0x000000FF
    let r = CGFloat(Float(Int(color >> 16) & mask)/255.0)
    let g = CGFloat(Float(Int(color >> 8) & mask)/255.0)
    let b = CGFloat(Float(Int(color) & mask)/255.0)
    
    return UIColor(red: r, green: g, blue: b, alpha: CGFloat(alpha))
}

Extension

extension UIColor {
    convenience init(colorCode: String, alpha: Float = 1.0){
        var scanner = NSScanner(string:colorCode)
        var color:UInt32 = 0;
        scanner.scanHexInt(&color)
        
        let mask = 0x000000FF
        let r = CGFloat(Float(Int(color >> 16) & mask)/255.0)
        let g = CGFloat(Float(Int(color >> 8) & mask)/255.0)
        let b = CGFloat(Float(Int(color) & mask)/255.0)
        
        self.init(red: r, green: g, blue: b, alpha: CGFloat(alpha))
    }
}

How to call

let hexColorFromFunction = UIColorFromRGB("F4C124", alpha: 1.0)
let hexColorFromExtension = UIColor(colorCode: "F4C124", alpha: 1.0)

You can also define your Hex Color from interface builder.