UIColor+Hex.h

#import <UIKit/UIKit.h>
#define RGBA_COLOR(R, G, B, A) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:A]
#define RGB_COLOR(R, G, B) [UIColor colorWithRed:((R) / 255.0f) green:((G) / 255.0f) blue:((B) / 255.0f) alpha:1.0f]
@interface UIColor (Hex)
+ (UIColor *)colorWithHex:(int32_t)hex;//hex:0XAABBCC
+ (UIColor *)colorWithHex:(int32_t)hex alpha:(CGFloat)alpha;//hex:0XAABBCC alpha:0~1.0
+ (UIColor *)colorWithHexString:(NSString *)color;
//從十六進(jìn)制字符串獲取顏色，
//color:支持@“#123456”、 @“0X123456”、 @“123456”三種格式
+ (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha;
@end

UIColor+Hex.m

@implementation UIColor (Hex)
union t_colors{
    u_int32_t hex;
    u_int8_t colors[4];
};
+ (UIColor *)colorWithHex:(int32_t)hex{
    return [self colorWithHex:hex alpha:1];
}
+ (UIColor *)colorWithHex:(int32_t)hex alpha:(CGFloat)alpha{
    union t_colors colors = {hex};
    return [UIColor colorWithRed:colors.colors[2]/255.0 green:colors.colors[1]/255.0 blue:colors.colors[0]/255.0 alpha:alpha];
}
+ (UIColor *)colorWithHexString:(NSString *)color alpha:(CGFloat)alpha
{
    //刪除字符串中的空格
    NSString *cString = [[color stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
    // String should be 6 or 8 characters
    if ([cString length] < 6)
    {
        return [UIColor clearColor];
    }
    // strip 0X if it appears
    //如果是0x開(kāi)頭的，那么截取字符串，字符串從索引為2的位置開(kāi)始，一直到末尾
    if ([cString hasPrefix:@"0X"])
    {
        cString = [cString substringFromIndex:2];
    }
    //如果是#開(kāi)頭的，那么截取字符串，字符串從索引為1的位置開(kāi)始，一直到末尾
    if ([cString hasPrefix:@"#"])
    {
        cString = [cString substringFromIndex:1];
    }
    if ([cString length] != 6)
    {
        return [UIColor clearColor];
    }
    
    // Separate into r, g, b substrings
    NSRange range;
    range.location = 0;
    range.length = 2;
    //r
    NSString *rString = [cString substringWithRange:range];
    //g
    range.location = 2;
    NSString *gString = [cString substringWithRange:range];
    //b
    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:alpha];
}

//默認(rèn)alpha值為1
+ (UIColor *)colorWithHexString:(NSString *)color
{
    return [self colorWithHexString:color alpha:1.0f];
}
@end