CODEWITHSUNDEEP
objective-cnsdatensdatecomponents
Andrew Z.
Andrew Z.

Reputation: 67

Incorrect date formatting?

Please help me with non-obvious code behavior

NSCalendar *calendar = [NSCalendar currentCalendar];

NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
dateComponents.hour     = 15;
dateComponents.minute   = 20;
dateComponents.calendar = calendar;

NSDate * endDate    = [calendar dateFromComponents:dateComponents];

EndDate is 0001-01-01 12:49:43 +0000. Why?

Hours value may be incorrect due to the difference in the time zones. Why such strange minutes and seconds value? Regards.

Upvotes: 2

Views: 77

Answers (1)

Michael Dorner
Michael Dorner

Reputation: 20155

If we are just considering the following code snippet

NSCalendar *calendar = [NSCalendar currentCalendar];        
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setCalendar:calendar];
NSDate *date = [calendar dateFromComponents:components];

date = 0000-12-31 23:06:32 +0000, because:

Calendars encapsulate information about systems of reckoning time in which the beginning, length, and divisions of a year are defined.

[...]

When there are insufficient components provided to completely specify an absolute time, a calendar uses default values of its choice. Apple Documentation

and

An NSDateComponents object is meaningless in itself; you need to know what calendar it is interpreted against, and you need to know whether the values are absolute values of the units, or quantities of the units. Apple Documentation

Actually, everything is fine and exactly what the documentation says.

Upvotes: 1

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