斯威夫特版本:

extension UIColor {
    convenience init?(var hex: String) {
        hex = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
        hex = (hex.hasPrefix("#")) ? hex.substringFromIndex(advance(hex.startIndex, 1)) : hex

        var value: UInt32 = 0
        if NSScanner(string: hex).scanHexInt(&value) {
            if count(hex) == 8 {
                self.init(red: CGFloat((value & 0xFF000000) >> 24) / 255.0,
                    green: CGFloat((value & 0x00FF0000) >> 16) / 255.0,
                    blue: CGFloat((value & 0x0000FF00) >> 8) / 255.0,
                    alpha: CGFloat((value & 0x000000FF)) / 255.0)
                return
            } else if count(hex) == 6 {
                self.init(red: CGFloat((value & 0xFF0000) >> 16) / 255.0,
                    green: CGFloat((value & 0x00FF00) >> 8) / 255.0,
                    blue: CGFloat(value & 0x0000FF) / 255.0,
                    alpha: 1.0)
                return
            }
        }
        self.init()
        return nil
    }
}

self.view.backgroundColor = colorWithHex(hex: yourColorCode)

从hexaDecimalCode创建颜色的代码

func colorWithHex (hex:String) -> UIColor {
    var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()

    if (cString.hasPrefix("#")) {
        cString.remove(at: cString.startIndex)
    }

    if ((cString.count) != 6) {
        return UIColor.gray
    }

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

上面的几个解决方案涉及到一些不必要的nsstring使用。这个UIColor类扩展更简单更快:

+ colorWithHex:(UInt32)hex alpha:(CGFloat)alpha
{
    return [UIColor colorWithRed:((hex & 0xFF0000) >> 16)/255.0
                           green:((hex & 0x00FF00) >> 8)/255.0
                            blue:( hex & 0x0000FF)/255.0
                           alpha:alpha];
}

简单来说:

return [UIColor colorWithHex:0x006400 alpha:1.0]; // HTML darkgreen

据我所知，没有从十六进制字符串到UIColor(或CGColor)的内置转换。但是，您可以很容易地为此目的编写几个函数—例如，参见iphone开发访问uicolor组件

有一个很好的UIColor类别，其中有许多功能。

用法:

textView.textColor = [UIColor colorWithHexString:textColorHex];
NSLog(@"Text Color Hex: %@", textColorHex);

其中textColorHex有一个形式的@“FFFFFF”没有#符号。

使用这个类别:

在文件UIColor+Hexadecimal.h中

#import <UIKit/UIKit.h>

@interface UIColor(Hexadecimal)

+ (UIColor *)colorWithHexString:(NSString *)hexString;

@end

在文件UIColor+Hexadecimal.m中

#import "UIColor+Hexadecimal.h"

@implementation UIColor(Hexadecimal)

+ (UIColor *)colorWithHexString:(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];
}

@end

你想在课堂上使用它:

#import "UIColor+Hexadecimal.h"

and:

[UIColor colorWithHexString:@"#6e4b4b"];