获取一周的第一天和最后一天

Question

I am using this method to get the current week first and last days:

NSDate *weekDate = [NSDate date];
NSCalendar *myCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *currentComps = [myCalendar components:( NSYearCalendarUnit | NSMonthCalendarUnit | NSWeekOfYearCalendarUnit | NSWeekdayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit) fromDate:weekDate];
int ff = currentComps.weekOfYear;
NSLog(@"1  %d", ff);

[currentComps setWeekday:1]; // 1: sunday
NSDate *firstDayOfTheWeek = [myCalendar dateFromComponents:currentComps];
[currentComps setWeekday:7]; // 7: saturday
NSDate *lastDayOfTheWeek = [myCalendar dateFromComponents:currentComps];

NSDateFormatter *myDateFormatter = [[NSDateFormatter alloc] init];
myDateFormatter.dateFormat = @"dd/MM/yyyy";
NSString *firstStr = [myDateFormatter stringFromDate:firstDayOfTheWeek];
NSString *secondStr = [myDateFormatter stringFromDate:lastDayOfTheWeek];

NSLog(@"first - %@ \nlast - %@", firstStr, secondStr);

And i want to know what i should change in this to get the next week first and last day and two weeks from now to?

Answer 1

To get the next week, add 7 days to firstDayOfTheWeek and then lastDayOfTheWeek .

NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:7];
NSDate *firstDayOfNextWeek = [myCalendar dateByAddingComponents:comps toDate:firstDayOfTheWeek options:0];

This code assumes a 7-day week. Ideally you would replace this assumption with code that gets the actual length of the week.

Side Note: Your code assume the week starts on Sunday. Many locales start their week on others days such as Monday. Change:

[currentComps setWeekday:1];

to:

[currentComps setWeekday:[myCalendar firstWeekday]];

I would then change your calculation of lastDayOfTheWeek to simply add 6 days to firstDayOfWeek .

Answer 2

Use Below code which returns index of current current weekly days. For example if its today is saturday than it will give you 7 means last day of week.

-(int)currentdayweeklynumber{

NSDate *CurrentDate = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd"];// you can use your format.

//Week Start Date 
NSCalendar *gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:CurrentDate];
int dayofweek = [[[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:CurrentDate] weekday];
NSLog(@" dayofweek=%d",dayofweek);
return dayofweek;

}

Using this number you add or subtract to get first or last of week. You can also use this get next week start and end date by just simple calculation.