NSCalendar first day of week

Question

Does anyone know if there is a way to set the first day of the week on a NSCalendar, or is there a calendar that already has Monday as the first day of the week, instead of Sunday. I'm currently working on an app that is based around a week's worth of work, and it needs to start on Monday, not Sunday. I can most likely do some work to work around this, but there will be a lot of corner cases. I'd prefer the platform do it for me.

Thanks in advance

Here's some the code that I'm using. it's saturday now, so what I would hope is that weekday would be 6, instead of 7. that would mean that Sunday would be 7 instead of rolling over to 0

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setFirstWeekday:0];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *todaysDate = [gregorian components:unitFlags fromDate:[NSDate date]];
int dayOfWeek = todaysDate.weekday;

Answer 1

Using the Calendar nextWeekend (iOS 10 or later) and ordinality (thanks @kris-markel). I've gotten Monday as first of the week for the en_US calendar.

Here is an example of it with fallback to firstWeekday:

extension Calendar {
    var firstWorkWeekday: Int {
        guard #available(iOS 10.0, *) else{
            return self.firstWeekday
        }
        guard let endOfWeekend = self.nextWeekend(startingAfter: Date())?.end else {
            return self.firstWeekday
        }
        return self.ordinality(of: .weekday, in: .weekOfYear, for: endOfWeekend) ?? self.firstWeekday
    }
}

Answer 2

Iv found out the way to display any weekday name using nscalender..using the following code.. Just open your console from xcode menu bar to see the results.Copy Paste the following code in your viewDidLoad method to get the first day of the week

NSDate *today = [NSDate date];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"MM/dd/yyyy :EEEE"];
NSString *dateString = [dateFormat stringFromDate:today];
NSLog(@"date: %@", dateString);
[dateFormat release];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
[components setDay:([components day]-([components weekday]-1))];

NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:@"MM/dd/yyyy :EEEE"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek];
NSLog(@"First_date: %@", dateString_first);

The Output will be:

 date: 02/11/2010 :Thursday
 First_date: 02/07/2010 :Sunday

since i had run this program on 2/11/2010 u will get the desired output depending on the current date.

Similarly if u want to get the first working day of the week i.e Monday's date then just modify the code a bit:

CHANGE :[components setDay:([components day]-([components weekday]-1))];

TO [components setDay:([components day]-([components weekday]-2))];

to get Mondays date for that week..

Similarly u can try to find the date of any of seven workdays by changing the integer -1,-2 and so on...

Hope u r question is answered..

Thanks, Bonson Dias

Answer 3

Below also covers the edge case,

- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate
{
    NSCalendar *calendar = [NSCalendar currentCalendar];


   NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
    [components setWeekday:2]; // 1 == Sunday, 7 == Saturday
    if([[calendar dateFromComponents:components] compare: curDate] == NSOrderedDescending) // if start is later in time than end
    {
        [components setWeek:[components week]-1];
    }

    return [calendar dateFromComponents:components];
}

Answer 4

Try this:

NSCalendar *yourCal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]
[yourCal setFirstWeekday:0];

Answer 5

My simple way of doing this is to get Monday = 0, Sunday = 6:

    NSDateComponents *dateComponents = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
    NSInteger dayNumStartingFromMonday = ([dateComponents weekday] - 2 + 7) % 7;    //normal: Sunday is 1, Monday is 2

Answer 6

I see misunderstanding in the other messages. The first weekday, whichever it is, has number 1 not 0. By default Sunday=1 as in the "Introduction to Date and Time Programming Guide for Cocoa: Calendrical Calculations":

"The weekday value for Sunday in the Gregorian calendar is 1"

For the Monday as a first workday the only remedy I have is brute force condition to fix the calculation

NSCalendar *cal=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [cal components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
// set to 7 if it's Sunday otherwise decrease weekday number
NSInteger weekday=[comps weekday]==1?7:[comps weekday]-1;