UIColor colorWithHex specify a hex code for use in Cocoa / Cocoa-Touch projects.

UIColor+Additions.m

+ (UIColor *)colorWithHex:(NSString *)hexCode
{
    if (!hexCode) {
        return nil;
    }
    
    NSString *hex = [hexCode copy];
    
    if ([hex hasPrefix:@"#"]) {
        hex = [hex substringFromIndex:1];
    }
    
    NSString *rStr = nil, *gStr = nil, *bStr = nil, *aStr = nil;
    
    if (hex.length == 3) {
        rStr = [hex substringWithRange:NSMakeRange(0, 1)];
        rStr = [NSString stringWithFormat:@"%@%@", rStr, rStr];
        gStr = [hex substringWithRange:NSMakeRange(1, 1)];
        gStr = [NSString stringWithFormat:@"%@%@", gStr, gStr];
        bStr = [hex substringWithRange:NSMakeRange(2, 1)];
        bStr = [NSString stringWithFormat:@"%@%@", bStr, bStr];
        aStr = @"FF";
    } else if (hex.length == 4) {
        rStr = [hex substringWithRange:NSMakeRange(0, 1)];
        rStr = [NSString stringWithFormat:@"%@%@", rStr, rStr];
        gStr = [hex substringWithRange:NSMakeRange(1, 1)];
        gStr = [NSString stringWithFormat:@"%@%@", gStr, gStr];
        bStr = [hex substringWithRange:NSMakeRange(2, 1)];
        bStr = [NSString stringWithFormat:@"%@%@", bStr, bStr];
        aStr = [hex substringWithRange:NSMakeRange(3, 1)];
        aStr = [NSString stringWithFormat:@"%@%@", aStr, aStr];
    } else if (hex.length == 6) {
        rStr = [hex substringWithRange:NSMakeRange(0, 2)];
        gStr = [hex substringWithRange:NSMakeRange(2, 2)];
        bStr = [hex substringWithRange:NSMakeRange(4, 2)];
        aStr = @"FF";
    } else if (hex.length == 8) {
        rStr = [hex substringWithRange:NSMakeRange(0, 2)];
        gStr = [hex substringWithRange:NSMakeRange(2, 2)];
        bStr = [hex substringWithRange:NSMakeRange(4, 2)];
        aStr = [hex substringWithRange:NSMakeRange(6, 2)];
    } else {
        // Unknown encoding
        return nil;
    }
    
    unsigned r, g, b, a;
    [[NSScanner scannerWithString:rStr] scanHexInt:&r];
    [[NSScanner scannerWithString:gStr] scanHexInt:&g];
    [[NSScanner scannerWithString:bStr] scanHexInt:&b];
    [[NSScanner scannerWithString:aStr] scanHexInt:&a];
    
    if (r == g && g == b) {
        // Optimal case for grayscale
        return [UIColor colorWithWhite:(((CGFloat)r) / 255.0f) alpha:(((CGFloat)a) / 255.0f)];
    } else {
        return [UIColor colorWithRed:(((CGFloat)r) / 255.0f) green:(((CGFloat)g) / 255.0f) blue:(((CGFloat)b) / 255.0f) alpha:(((CGFloat)a) / 255.0f)];
    }
}