NSCalendar dateFromComponents returns strange date [duplicate] - ios

Question

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NSDateComponents weekOfYear returns wrong date
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Closed 5 years ago.
The NSCalendar dateFromComponents function returns unexpected date.
Here is the use case :
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
[calendar setTimeZone:timeZone];
Where timezone is: Local Time Zone (Europe/Paris (GMT+1) offset 3600)
NSDateComponents *finalComponents = [calendar components:NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitYear | NSCalendarUnitWeekOfYear | NSCalendarUnitWeekday fromDate:now];
[finalComponents setWeekday:weekDay];
At this point, I have the following value for finalComponents :
Calendar Year: 2018
Hour: 23
Minute: 59
Week of Year: 1
Weekday: 2
The [calendar dateFromComponents:finalComponents] returns 2018-12-31 22:59:00 +0000 and I expect 2017-12-31 22:59:00 +0000
Any help is welcome

Answer 1

May this help you..!
Note: I used value for weekday as 1 (for IST it gives me correct date). You can update it according to your timezone.
NSCalendar *calendar = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierGregorian];
[calendar setTimeZone:NSTimeZone.localTimeZone];
NSDate *currentDate = [NSDate date];
NSDateComponents *finalComponents = [calendar components:NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitYear | NSCalendarUnitWeekOfYear | NSCalendarUnitWeekday fromDate:currentDate];
[finalComponents setWeekday: 1];
[finalComponents setYearForWeekOfYear:finalComponents.year]; // Update year dynamically here
NSLog(#"Current Date: %#",currentDate);
NSLog(#"Print Date: %#",[calendar dateFromComponents:finalComponents]);
Current Date: Fri Jan 5 20:00:53 2018
Print Date: Sun Dec 31 20:00:00 2017
Ask me, if you need any further help..!

Answer 2

The components that you extract seem to be ambiguous, resulting in a weird date. If you include the NSCalendarUnitYearForWeekOfYear in your selected components, you should get the correct year:
NSDateComponents *finalComponents = [calendar components:NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitYear | NSCalendarUnitWeekOfYear | NSCalendarUnitWeekday | NSCalendarUnitYearForWeekOfYear fromDate:now];
For me adding the extra component makes it so that I get the correct year.