Difference between NSDate and NSDateComponent value for the same date
I created a simple function to get first and last day of a week for a day in it. Looking at the NSLog output i found that different values are returned from a NSDate descriptor and component day for the same date, why ?
Here NSLog outputs:
NSDATE: 2011-04-03 22:00:00 +0000, DAY COMPONENT: 4
NSDATE: 2011-04-09 22:00:00 +0000, DAY COMPONENT: 10
As you can see, NSDATE is 3 of April and day component is 4 for the first row, and respectively 9 and 10 for the second one.
Here the code:
NSDate *date = [NSDate date]; //Today is April 5th 2011
NSCalendar *cal =[[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
[cal setFirstWeekday:2]; //My week starts from Monday
//DEFINE BEGINNING OF THE WEEK
NSDate *beginningOfWeek = nil;
[cal rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek interval:nil forDate:date];
NSDateComponents *beginComponents = [cal components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit) fromDate:beginningOfWeek];
//DEFINE END OF THE WEEK, WITH 6 days OFFSET FROM BEGINNING
NSDateComponents *offset = [[NSDateComponents alloc]init];
[offset setDay:6];
NSDate *endOfWeek = [cal dateByAddingComponents:offset toDate:beginningOfWeek options:0];
NSDateComponents *endComponents = [cal components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit) fromDate:endOfWeek];
NSLog(@"NSDATE: %@, DAY COMPONENT: %d",begi开发者_运维问答nningOfWeek, [beginComponents day]);
NSLog(@"NSDATE: %@, DAY COMPONENT: %d",endOfWeek, [endComponents day]);
Your dates are being printed with a timezone of +0000 (UTC), while your NSCalendar instance (and therefore your NSDateComponents) is using your device's default timezone (which I would guess is UTC+2).
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