CODEWITHSUNDEEP
iosnsdatensdateformatter
SCar88
SCar88

Reputation: 110

Creating NSDate object with specific time zone

I've written a method that accepts a NSDate object and should turn it into a NSDate object with EST time zone. The way I've seen other people accomplish this is by using a date formatter to change the date to a string with the specified time zone. The issue is when I try to change that string back to a NSDate object using "dateFromString". 

- (NSDate*)turnToEST:(NSDate*)date
{
NSLog(@"turnToEST called with date %@", date);

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"EST"]];

NSString *stringFromDate = [dateFormatter stringFromDate:date];

NSLog(@"date formatted is %@", stringFromDate);

NSDate *dateFromString = [[NSDate alloc] init];

NSDateFormatter *dateFormatter2 = [[NSDateFormatter alloc]init];
[dateFormatter2 setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

dateFromString = [dateFormatter2 dateFromString:stringFromDate];

NSLog(@"date has been changed to %@", dateFromString);

return date;
}

With output...

turnToEST called with date 2013-12-19 14:15:17 +0000
date formatted is 2013-12-19 09:15:17
date has been changed to 2013-12-19 14:15:17 +0000

I'm not sure why this is any different than

Converting NSString to NSDate (and back again)

Upvotes: 0

Views: 1353

Answers (1)

Sixten Otto
Sixten Otto

Reputation: 14816

NSDate values do not have an associated time zone, they represent an abstract moment in time. So "a NSDate object with EST time zone" isn't a thing that exists. Time zones only come into play when formatting them for output, or trying to do calendar-based math.

NSLog always uses UTC when printing its output.

So you're taking a moment in time, formatting it to a string in a particular time zone, and then parsing it back into the same moment in time. That's working as intended.

Upvotes: 4

Related Questions