/**
 @return 如果版本号相等返回0，第一个版本号高于第二个，返回1，否则返回 -1.
 */
- (NSInteger)compareVersion:(NSString *)version1 andVersion:(NSString *)version2{
    NSInteger res = 0;
    NSArray *arry1 = [version1 componentsSeparatedByString:@"."];
    NSArray *arry2 = [version2 componentsSeparatedByString:@"."];

    NSInteger idx1 = 0;
    NSInteger idx2 = 0;

    while (res == 0 && (idx1 < arry1.count || idx2 < arry2.count)) {

        id num1 = idx1 < arry1.count ? arry1[idx1] : 0;
        id num2 = idx2 < arry2.count ? arry2[idx2] : 0;

        if ([num1 integerValue] > [num2 integerValue]) {
            res = 1;
        }else if ([num1 integerValue] < [num2 integerValue]) {
            res = -1;
        }

        idx1++;
        idx2++;
    }
    return res;
}