Why am I getting wrong time output with correct timezone?

Question

Why am I getting this output time:

2013-01-12 18:24:37.783 Code testings[10328:c07] 0001-01-01 17:12:52 +0000

when I run this code:

NSCalendar *calendar = [NSCalendar currentCalendar];
calendar.timeZone = [NSTimeZone localTimeZone];

NSDateComponents *components = [calendar components:NSHourCalendarUnit fromDate:[NSDate date]];
components.hour   = 17;
components.minute = 47;
components.second = 0;

NSDate *fire = [calendar dateFromComponents:components];
NSLog(@"%@", fire);

I have tried default timezone, system timezone. And it always gives me an output with different minutes and seconds! plus wrong date 0001-01-01!!!! Any idea why?

Additional Tests:

When running this code:

NSCalendar *calendar = [NSCalendar currentCalendar];
calendar.timeZone = [NSTimeZone localTimeZone];
NSDateComponents *components = [calendar components:NSHourCalendarUnit fromDate:[NSDate date]];
components.hour   = (components.hour + 1) % 24;
components.minute = 0;
components.second = 0;
NSDate *fire = [calendar dateFromComponents:components];
NSLog(@"%@", fire);

It gives me this output:

2013-01-12 18:41:41.552 Code testings[10648:c07] 0001-01-01 18:25:52 +0000

2013-01-12 18:42:16.274 Code testings[10648:c07] 0001-01-01 18:25:52 +0000

2013-01-12 18:42:30.310 Code testings[10648:c07] 0001-01-01 18:25:52 +0000

Can you tell me, what you want to perform, your requirement? — Anoop Vaidya, Jan 12 '13 at 17:55
for now firing a notification.. but it's the general behaviour I was wondering about. — Whylonely, Jan 12 '13 at 18:27

Peter Warbo · Accepted Answer · 2013-01-12T18:12:08.833

7

You are mising the year, month and day components.

Do:

NSDateComponents *components = [calendar components:NSUIntegerMax fromDate:[NSDate date]];

Now that should give you the correct date.

Side note: since the NSCalendarUnit is a bitfield typedef for NSUInteger, I pass in NSUIntegerMax to retrieve all possible calendar units. That way I don't have to have a massive bitwise OR statement.

edited Jan 12 '13 at 18:12

answered Jan 12 '13 at 17:56

Peter Warbo

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1

nice trick with NSUIntegerMax, but as Whylonely seems to be a beginner, you should probably explain that. anyway +1 – vikingosegundo Jan 12 '13 at 18:05
I don't take credit for it though, it's a trick I learned here on SO :) – Peter Warbo Jan 12 '13 at 18:12
2

@PeterWarbo Thanks for the smart answer. NSUIntegerMax it helped me a lot. – Whylonely Jan 12 '13 at 18:28
Always thought there had to be a better way than having a super long bitwise `or` statement, awesome tip with `NSUIntegerMax`! – rebello95 Mar 02 '15 at 18:30

zaph · Answer 2 · 2013-01-12T18:06:43.463

You also need to request the year, month and day with the calendar components: method.

From Apple docs:

An instance of NSDateComponents is not responsible for answering questions about a date beyond the information with which it was initialized.

NSDateComponents *components = [calendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit fromDate:[NSDate date]];

NSLog of the date will display the time with the default timezone.

Why am I getting wrong time output with correct timezone?

2 Answers2