如何獲取週末的日期？

Question

我想使用週末的日期在NSLocalNotification中使用它，但我不知道如何獲取它，我試圖用數學方法來做，但有時候我得到的數字大於本月的日子。

Answer 1

你有關獲取日期第一個問題就可以解決的：

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支持多種日曆，我不知道，如果使用這些日曆的所有文化都有周末，如果一個概念，他們總是意味着有兩天。

你還需要處理一些事情：即使在使用格里曆的國家，一週也可能從星期一或星期日開始。

但是，如果我們假設一個週末等同於週六和週日，這可能對你有所幫助：

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];