ios - 计算时差iOS

Question

我这样写来计算时差。

+ (NSInteger)hoursBetweenDate:(NSDate*)fromDateTime andDate:(NSDate *)toDateTime
{
    NSDate *fromDate;
    NSDate *toDate;

    NSCalendar *calendar = [NSCalendar currentCalendar];

    [calendar setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

    [calendar rangeOfUnit:NSHourCalendarUnit startDate:&fromDate
             interval:NULL forDate:fromDateTime];
    [calendar rangeOfUnit:NSHourCalendarUnit startDate:&toDate
             interval:NULL forDate:toDateTime];

    NSDateComponents *difference = [calendar components:NSHourCalendarUnit
                                           fromDate:fromDate toDate:toDate options:0];

    return [difference hour];
}

问题是，如果输入是这样，


2016-03-09 07:58:39 +0000(fromDateTime)
2016-03-09 09:07:44 +0000(toDateTime)，


差异总是2小时。实际上，应该是1小时10分钟。结果，我只想显示1小时。有没有办法向上或向下取整？

Answer 1

如果您只是对日期之间的“未格式化”小时数感兴趣，则可以使用NSTimeInterval并轻松进行计算。

+(int)fullHoursBetweenDate:(NSDate *)date1 andDate:(NSDate *)date2 {
    NSTimeInterval interval = [date2 timeIntervalSinceDate:date1];
    return (int)interval / 3600;
}