两个时期时间比较大小

-(int)compareOneDay:(NSDate *)oneDay withAnotherDay:(NSDate *)anotherDay
{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm"];
    NSString *oneDayStr = [dateFormatter stringFromDate:oneDay];
    NSString *anotherDayStr = [dateFormatter stringFromDate:anotherDay];
    NSDate *dateA = [dateFormatter dateFromString:oneDayStr];
    NSDate *dateB = [dateFormatter dateFromString:anotherDayStr];
    NSComparisonResult result = [dateA compare:dateB];
    if (result == NSOrderedDescending) {
        //NSLog(@"oneDay比 anotherDay时间晚");
        return 1;
    }
    else if (result == NSOrderedAscending){
        //NSLog(@"oneDay比 anotherDay时间早");
        return -1;
    }
    //NSLog(@"两者时间是同一个时间");
    return 0;
}