convert NSDate to NSString is ok,but reverse is wrong

Question

I want to change UTC time to local time by NSDateFormatter.

But it doesn't work what I expect.

-(NSDateFormatter *)df
{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss ZZZ"];
    dateFormatter.timeZone = [NSTimeZone defaultTimeZone];

    return dateFormatter;
}


...

NSDate *now = [NSDate date];

NSString *dateStr = [[self df] stringFromDate:now];
// dateStr is correct.
//dateStr is 2013-12-26 20:32:26 +0900

NSLog(@"dateStr is %@",dateStr);

NSDate *date = [[self df] dateFromString:dateStr];
// date is wrong.
//date is 2013-12-26 11:32:26 +0000

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

Why date is not equal to dateStr.

I want date return 2013-12-26 10:32:26 +0900

Do you have any idea? Thanks in advance.

Or [Why NSDate is reporting the wrong date?](http://stackoverflow.com/questions/6741519/why-nsdate-is-reporting-the-wrong-date) (and probably some more ...) — Martin R, Dec 26 '13 at 11:43

score 3 · Accepted Answer · answered Dec 26 '13 at 11:44

The NSDate *date that you get is correct - 2013-12-26 11:32:26 +0000 is the UTC representation of 2013-12-26 20:32:26 +0900. NSDate objects do not embed the time zone - they represent an abstract point in time, not a point in time at any specific time zone.

NSLog always logs time in in UTC, because it calls the description method of NSDate.

score 0 · Answer 2 · answered Dec 26 '13 at 11:43

0

You need to change the time zone of your final Date to get the desired result.

answered Dec 26 '13 at 11:43

Akshat Singhal

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2

`NSDate` objects don't have time zones. – Sergey Kalinichenko Dec 26 '13 at 11:46

convert NSDate to NSString is ok,but reverse is wrong

2 Answers2