获取一周的开始和结束日期。 月份、周数和年份作为用户输入给出

Question

My code should bring the date of a particular week, when the user provide the month, week number, and year. For example: If my user input is month (String) --> "October", week (Int) -- > 1, year (int) --> 2019, the above input should give the response like startDate --> 01/10/2019, endDate --> 07/10/2019.

If the user give the last week of any month it should bring the remaining days in the month. Week calculated from Sunday.

My attempted code giving start date and end date for current month / current

NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

cal.firstWeekday = 1;// set first week day to Monday
// 1: Sunday, 2: Monday, ..., 7:Saturday

NSDate *now = [NSDate date];
NSDate *startOfTheWeek;
NSDate *endOfWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSCalendarUnitWeekOfYear
       startDate:&startOfTheWeek
        interval:&interval
         forDate:now];
//startOfTheWeek holds the beginning of the week

endOfWeek = [startOfTheWeek dateByAddingTimeInterval:interval - 1];
// endOfWeek now holds the last second of the last week day

[cal rangeOfUnit:NSCalendarUnitDay
       startDate:&endOfWeek
        interval:NULL
         forDate:endOfWeek];
// endOfWeek now holds the beginning of the last week day

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateStyle = NSDateFormatterShortStyle;
formatter.timeStyle = NSDateFormatterShortStyle;

NSLog(@"start: %@", [formatter stringFromDate:startOfTheWeek]);
NSLog(@"end:   %@", [formatter stringFromDate:endOfWeek]);

Answer 1

I came up with this that fulfills your criteria I think

NSInteger year = 2019;
NSInteger month = 11;
NSInteger week = 1;

NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

cal.firstWeekday = 2;

NSDateComponents *comps = [NSDateComponents new];
comps.calendar = cal;
comps.year = year;
comps.month = month;
comps.weekday = cal.firstWeekday;
comps.weekdayOrdinal = week - 1;

NSDateComponents *startOfTheMonthComps = [NSDateComponents new];
startOfTheMonthComps.year = year;
startOfTheMonthComps.month = month;
NSDateComponents *endOfTheMonthComps = [NSDateComponents new];
endOfTheMonthComps.year = year;
endOfTheMonthComps.month = month + 1;

NSDate *startOfTheMonth = [cal dateFromComponents:startOfTheMonthComps];
NSDate *endOfTheMonth = [[cal dateFromComponents:endOfTheMonthComps] dateByAddingTimeInterval:-1];

NSDate *date = [comps date];
NSDate *startOfTheWeek;
NSDate *endOfWeek;
NSTimeInterval interval;
[cal rangeOfUnit:NSCalendarUnitWeekOfYear
       startDate:&startOfTheWeek
        interval:&interval
         forDate:date];

endOfWeek = [startOfTheWeek dateByAddingTimeInterval:interval];

startOfTheWeek = [startOfTheWeek dateByAddingTimeInterval:-1];


if ([startOfTheWeek compare:startOfTheMonth] == NSOrderedAscending) {
    startOfTheWeek = startOfTheMonth;
}

if ([endOfTheMonth compare:endOfWeek] == NSOrderedAscending) {
    endOfWeek = endOfTheMonth;
}
NSLog(@"start %@", startOfTheWeek);
NSLog(@"end %@", endOfWeek);

So for 1st week of November you get Fri Nov 1 and Mon Nov 4 and for last week of September - week 6 Sun Sep 29 and Mon Sep 30