NSDate独立于时区？ [英] NSDate independent of timezone?

问题描述

我有一个应用程序显示某些渡轮旅行的时间表。

如果我前往不同的时区 - 比如说落后4小时，那么10点的渡轮旅行现在显示早上6点？

我知道这与如何根据时区处理日期有关，但我无法弄清楚如何改变这种行为。 / p>

目前，这是我如何获取日期并在UILabel上显示：

  NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init]; 
 [dateFormatter setDateFormat：@HH：mm]; 
 [self.departureTime setText：[dateFormatter stringFromDate：[self.route objectForKey：@departureTime]]]; 
 [self.arrivalTime setText：[dateFormatter stringFromDate：[self.route objectForKey：@arrivalTime]]]; 
 [dateFormatter release]; 
  

提前感谢您的帮助。

解决方案

您需要存储渡轮所在的时区并为该时区设置格式。

  NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init]; 
 [dateFormatter setDateFormat：@HH：mm]; 
 
 NSDate * now = [NSDate date]; 
 NSLog（@now：％@，[dateFormatter stringFromDate：now]）; 
 
 NSTimeZone * timeZone = [NSTimeZone timeZoneForSecondsFromGMT：（ -  8 * 3600）]; 
 [dateFormatter setTimeZone：timeZone]; 
 NSLog（@按时区调整：％@，[dateFormatter stringFromDate：now]）; 
  

输出：

  2011-10-10 20：42：23.781 Craplet [2926：707]现在：20：42 
 2011-10-10 20：42：23.782 Craplet [2926：707]根据时区调整： 16:42 
  

I have an app that displays a timetable of certain ferry trips.

If I travel to a different timezone - say 4 hours behind, a 10am ferry trip now shows up as 6am?

I know this has got to do with how dates are treated based on their timezones, but I can't work out how to change that behaviour.

At the moment here's how I am getting the date and displaying it on a UILabel:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"HH:mm"];
[self.departureTime setText:[dateFormatter stringFromDate:[self.route objectForKey:@"departureTime"]]];
[self.arrivalTime setText:[dateFormatter stringFromDate:[self.route objectForKey:@"arrivalTime"]]];
[dateFormatter release];

Thanks in advance for your help.

解决方案

You'll need to store the timezone that the ferry ride is taking place in and format it for that timezone.

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"HH:mm"]; 

NSDate *now = [NSDate date];   
NSLog(@"now:%@", [dateFormatter stringFromDate:now]);

NSTimeZone *timeZone = [NSTimeZone timeZoneForSecondsFromGMT:(-8 * 3600)];     
[dateFormatter setTimeZone:timeZone];
NSLog(@"adjusted for timezone: %@", [dateFormatter stringFromDate:now]);

Outputs:

2011-10-10 20:42:23.781 Craplet[2926:707] now:20:42
2011-10-10 20:42:23.782 Craplet[2926:707] adjusted for timezone: 16:42

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