我正在尝试使用NSDateComponents来测试动态日期是否发生在“今天”。我用它来提取年/月/日,然后比较两个NSDate的值。从理论上讲,这应该起作用。我在东海岸,所以EST,UTC的时间是-5。
当前实际时间:美国东部标准时间12:40:53
这是UTC中正确的NSDate。时间是正确的UTC:
这是我的日志,显示每个日期。它将日期转换为本地时区2016-01-19 07:00:00。由于当前日期是一天中的某一天,因此-5小时的偏移不会导致它偏移日期。然而,午夜时分又回到了一天。我如何才能尊重UTC?
NSLog:
2016-1-19 12:40:53 (America/New_York (EST) offset -18000),
2016-1-18 19:0:0 (America/New_York (EST) offset -18000)
代码:
NSDateComponents *current = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay |NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond |NSCalendarUnitTimeZone fromDate:_date];
NSDateComponents *activity = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay |NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond |NSCalendarUnitTimeZone fromDate:activityModel.date];
// attempt to set timezones to UTC manually, doesn't change anything
activity.calendar = [NSCalendar currentCalendar];
activity.calendar.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];
current.calendar = [NSCalendar currentCalendar];
current.calendar.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];
NSLog(@"%ld-%ld-%ld %ld:%ld:%ld (%@), %ld-%ld-%ld %ld:%ld:%ld (%@)", (long)[current year],(long)[current month], (long)[current day], (long)[current hour], (long)[current minute], (long)[current second], [current timeZone].description, (long)[activity year], (long)[activity month], (long)[activity day],(long)[activity hour], (long)[activity minute], (long)[activity second],[current timeZone].description);
if([current day] == [activity day] &&
[current month] == [activity month] &&
[current year] == [activity year] &&
[current era] == [activity era]) {
// do something if activity on current day
}
您正在更改的时区NSDateComponents
。但是您想在调用components
(或调用NSCalendar
日期检查例程)之前更改日历的时区,例如:
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
calendar.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
if ([calendar isDate:_date inSameDayAsDate:activityModel.date]) {
NSLog(@"same");
} else {
NSLog(@"diff");
}
但是,如果当地时间是2016-01-19 21:00:00 -0500
(例如UTC 20),该怎么办?您是否要说示例中的活动日期也是同一天?如果是这样,那么您实际上是想将本地日历用于_date
,将UTC用于activityModel.date
,例如:
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *current = [calendar components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay |NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond |NSCalendarUnitTimeZone fromDate:_date];
calendar.timeZone = [NSTimeZone timeZoneForSecondsFromGMT:0];
NSDateComponents *activity = [calendar components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay |NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond |NSCalendarUnitTimeZone fromDate:activityModel.date];
if ([current day] == [activity day] && [current month] == [activity month] && [current year] == [activity year] && [current era] == [activity era]) {
NSLog(@"same");
} else {
NSLog(@"diff");
}
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