iOS RGB颜色封装

使用类别创建

.h文件

#import <UIKit/UIKit.h>

@interface UIColor (HexColor)

+ (UIColor *)colorWithHex:(NSString *)hex;

@end

.m文件

#import "UIColor+HexColor.h"

@implementation UIColor (HexColor)

+ (UIColor *)colorWithHex:(NSString *)hex {
    unsigned int red, green, blue;
    NSRange range;
    range.length = ;

    range.location = ;
    if (hex.length == ) {
        range.location = ;
    }
    [[NSScanner scannerWithString:[hex substringWithRange:range]]scanHexInt:&red];
    range.location += ;
    [[NSScanner scannerWithString:[hex substringWithRange:range]]scanHexInt:&green];
    range.location += ;
    [[NSScanner scannerWithString:[hex substringWithRange:range]]scanHexInt:&blue];

    return [UIColor colorWithRed:(float)(red / 255.0) green:(float)(green / 255.0) blue:(float)(blue / 255.0) alpha:1.0];
}

@end

还有一个类似的方法，代码如下：

+ (UIColor *)colorWithHex:(NSString *)hex {  
        // Remove `#` and `0x`  
        if ([hex hasPrefix:@"#"]) {  
             hex = [hex substringFromIndex:];  
        } else if ([hex hasPrefix:@"0x"]) {  
            hex = [hex substringFromIndex:];  
        }  
      
        // Invalid if not 3, 6, or 8 characters  
        NSUInteger length = [hex length];  
        if (length !=  && length !=  && length != ) {  
            return nil;  
        }  
      
        // Make the string 8 characters long for easier parsing  
        if (length == ) {  
            NSString *r = [hex substringWithRange:NSMakeRange(, )];  
            NSString *g = [hex substringWithRange:NSMakeRange(, )];  
            NSString *b = [hex substringWithRange:NSMakeRange(, )];  
            hex = [NSString stringWithFormat:@"%@%@%@%@%@%@ff",                   r, r, g, g, b, b];  
        } else if (length == ) {  
            hex = [hex stringByAppendingString:@"ff"];  
        }  
  
    CGFloat red = [[hex substringWithRange:NSMakeRange(, )] _hexValue] / 255.0f;  
        CGFloat green = [[hex substringWithRange:NSMakeRange(, )] _hexValue] / 255.0f;  
        CGFloat blue = [[hex substringWithRange:NSMakeRange(, )] _hexValue] / 255.0f;  
        CGFloat alpha = [[hex substringWithRange:NSMakeRange(, )] _hexValue] / 255.0f;  
          
    return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];  

}