颜色转进制

+ (UIColor *)hexColor:(NSString *)hexColor{
    if ([hexColor length] < 6) {
        return nil;
    }
    unsigned int red,green,blue;
    NSRange range;
    range.length = 2;
    range.location = 0;
    [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&red];
    range.location = 2;
    [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&green];
    range.location = 4;
    [[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&blue];
    return [UIColor colorWithRed:(float)(red/255.f) green:(float)(green / 255.f) blue:(float)(blue / 255.f) alpha:1.f];
}

[[NSScanner scannerWithString:[hexColor substringWithRange:range]] scanHexInt:&red];

把你指定的range的子串取出来（应该是16进制格式的），转成10进制整数存到red变量里。