如何获取周末的日期？

Question

我想使用周末的日期在NSLocalNotification中使用它，但我不知道如何获取它，我试图用数学方法来做，但有时候我得到的数字大于本月的日子。

Answer 1

你有关获取日期第一个问题就可以解决的：

NSCalendar *calender=[NSCalendar currentCalendar]; 
NSRange daysRange=[calender rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:[NSDate date]]; 
NSUInteger numberOfDaysInMonth=daysRange.length; 
//NSLog(@"num of days in current month : %ld",numberOfDaysInMonth); 

NSDateComponents *dateComponents = [calender components:NSWeekdayCalendarUnit fromDate:[NSDate date]]; 
NSInteger dayCount=[dateComponents weekday]; 
//if today itself is saturday what you want to display? today or upcoming one... then do small changes here, for sat & sun. 

NSInteger daysForSaturday=7-dayCount; 

NSDateFormatter *formatter = [[NSDateFormatter alloc] init]; 
[formatter setDateFormat:@"dd"]; 
NSUInteger todaysDate = [[formatter stringFromDate:[NSDate date]]integerValue]; 

// NSLog(@"Today is : %@",todaysDate); 

NSUInteger comingSaturday=todaysDate+daysForSaturday;  
if (comingSaturday>numberOfDaysInMonth) { 
    comingSaturday-=numberOfDaysInMonth; 
} 
NSUInteger comingSunday=comingSaturday+1; 

NSLog(@"Coming.. Sat is : %ld, Sun in : %ld",comingSaturday, comingSunday); 

Answer 2

需要注意的是IOS支持多种日历，我不知道，如果使用这些日历的所有文化都有周末，如果一个概念，他们总是意味着有两天。

你还需要处理一些事情：即使在使用格里历的国家，一周也可能从星期一或星期日开始。

但是，如果我们假设一个周末等同于周六和周日，这可能对你有所帮助：

NSDate *referenceDate = [NSDate date]; 
NSDate *startOfThisWeek; 
NSDate *saturday; 

NSUInteger backupStartWeekday = [[NSCalendar currentCalendar] firstWeekday]; 
[[NSCalendar currentCalendar] setFirstWeekday:1]; // ensure week begins at sunday 

[[NSCalendar currentCalendar] rangeOfUnit:NSWeekCalendarUnit 
           startDate:&startOfThisWeek 
           interval:NULL 
            forDate:referenceDate]; 

NSDateComponents *components = [[NSDateComponents alloc] init]; 
components.day = [[NSCalendar currentCalendar] maximumRangeOfUnit:NSWeekdayCalendarUnit].length; //the start of the next week 

components.day = components.day - 2; 
saturday = [[NSCalendar currentCalendar] dateByAddingComponents:components 
                 toDate:startOfThisWeek 
                 options:0]; 

[[NSCalendar currentCalendar] setFirstWeekday:backupStartWeekday];