身份证校验

+ (BOOL)stringWithIDCardValidate:(NSString *)idCard{
    
    BOOL flag = YES;
    if (idCard.length <= 0)
    {
        flag = NO;
        return flag;
    }
    
    NSString *regex2 = @"^(^[1-9]\\d{7}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])\\d{3}$)|(^[1-9]\\d{5}[1-9]\\d{3}((0\\d)|(1[0-2]))(([0|1|2]\\d)|3[0-1])((\\d{4})|\\d{3}[Xx])$)$";
    NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];
    flag = [identityCardPredicate evaluateWithObject:idCard];
    
    
    //若是经过该验证，说明身份证格式正确，但准确性还需计算
    if(flag)
    {
        if(idCard.length==18)
        {
            //将前17位加权因子保存在数组里
            NSArray * idCardWiArray = @[@"7", @"9", @"10", @"5", @"8", @"4", @"2", @"1", @"6", @"3", @"7", @"9", @"10", @"5", @"8", @"4", @"2"];
            
            //这是除以11后，可能产生的11位余数、验证码，也保存成数组
            NSArray * idCardYArray = @[@"1", @"0", @"10", @"9", @"8", @"7", @"6", @"5", @"4", @"3", @"2"];
            
            //用来保存前17位各自乖以加权因子后的总和
            
            NSInteger idCardWiSum = 0;
            for(int i = 0;i < 17;i++)
            {
                NSInteger subStrIndex = [[idCard substringWithRange:NSMakeRange(i, 1)] integerValue];
                NSInteger idCardWiIndex = [[idCardWiArray objectAtIndex:i] integerValue];
                
                idCardWiSum+= subStrIndex * idCardWiIndex;
                
            }
            
            //计算出校验码所在数组的位置
            NSInteger idCardMod=idCardWiSum%11;
            
            //获得最后一位身份证号码
            NSString * idCardLast= [idCard substringWithRange:NSMakeRange(17, 1)];
            
            //若是等于2，则说明校验码是10，身份证号码最后一位应该是X
            if(idCardMod==2)
            {
                if([idCardLast isEqualToString:@"X"]||[idCardLast isEqualToString:@"x"])
                {
                    return flag;
                }else
                {
                    flag =  NO;
                    return flag;
                }
            }else
            {
                //用计算出的验证码与最后一位身份证号码匹配，若是一致，说明经过，不然是无效的身份证号码
                if([idCardLast isEqualToString: [idCardYArray objectAtIndex:idCardMod]])
                {
                    return flag;
                }
                else
                {
                    flag =  NO;
                    return flag;
                }
            }
        }
        else
        {
            flag =  NO;
            return flag;
        }
    }
    else
    {
        return flag;
    }
}