Find the NSDate for next Monday [closed]

Question

I want to get the date of the next Monday after the current date.

So if today's date is 2013-08-09 (Friday) then I want to get the date 2013-08-12.

How can I do this?

Edd

Although this is a simple question and requires little effort, dates are annoying as hell in any language so i don't see why you should be down-voted. – Velate

Answer 1

This piece of code should get what you want. It simply calculates how many days are from monday and append it from current's date.

NSDate *now = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [calendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit fromDate:now];

NSUInteger weekdayToday = [components weekday];  
NSInteger daysToMonday = (9 - weekdayToday) % 7;

NSDate *nextMonday = [now dateByAddingTimeInterval:60*60*24*daysToMonday];

Untested, but should work, and without worrying about changing first dates of calendar.

And it can even be easily addapted to every another day of the week, just change the 9inside (9 - weekdayToday) % 7; by 7 + weekDayYouWant, remembering that sunday = 1, monday = 2...

Intuition

Thanks Lucas , works perfectly. Just one thing , if today is Monday then I want to show next Monday instead of this Monday. Can you tell me how can I achieve this ? Thanks again – Joiner

I don't think there's a elegant way to change the behaviour for just one day like that. But you can add (not replace) something like that, before the nextMonday code: daysToMonday = (daysToMonday == 0) ? 7 : daysToMonday; . In this way, you would be adding 7 days instead of 0 days when the current day is monday. If you find a better solution for this case, just let me know – Intuition

won't work for daylight savings time. See this for modified solution for adding the days #5068285 – Nawrocki

Since macOS 10.9 / iOS 8 the recommended way is nextDayAfterDate:matchingComponents:options: of NSCalendar. It can consider daylight saving changes all over the world and is much more reliable than 86400. – Incidence

Answer 2

You can use NSCalendar method dateFromComponents: passing a properly initiated NSDateComponents object

NSDateComponents *components = [[NSCalendar currentCalendar] components: NSYearCalendarUnit | NSWeekOfYearCalendarUnit fromDate:[NSDate date]];

NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setWeekOfYear:[components weekOfYear] + 1];
[comps setWeekday:1];
[comps setYear:[components year]];
NSCalendar *calendar = [NSCalendar currentCalendar];
[calendar setFirstWeekday:2]; //This needs to be checked, which day is monday?
NSDate *date = [calendar dateFromComponents:comps];

Something along these lines could work (blindly typed)

Privacy

assuming the week begins in sunday (week day = 0), wouldn't this code get the monday of the week after instead of only the day after when running on sundays? – Intuition

Weekday units are the numbers 1 through n, where n is the number of days in the week. For example, in the Gregorian calendar, n is 7 and Sunday is represented by 1. So yes, probably the code needs to be changed – Privacy

I slightly edited the code to take this into account. Of course one should also check that the current day isn't the last week of the year and so on.. – Privacy

@Privacy its not work, but i like that approach. – Prussianism