計算當前周的第一天和最後一天

參考預先回答的問題在：Getting first and last days of current week 計算當前周的第一天和最後一天

有在上面的鏈接兩個答案。其中一個是理論性的，另一個是PyObjC（Python-Objective C橋語言）語言，快速谷歌搜索證實PyObjC不能與iPhone SDK一起工作。

因此，關於這個問題，如何將PyObjC代碼翻譯爲與iPhone SDK兼容。

目標：假設今天（週二）是19日，太陽。是第17（周開始）和週六。 23日是週末。我想得到像19/01 - 23/01這樣的字符串[即本週開始周（週末）]

2010-01-17 Dot

蘋果提供了一個很好的例子：你可以看到詳細https://developer.apple.com/Library/ios/#documentation/Cocoa/Conceptual/DatesAndTimes/Articles/dtCalendricalCalculations.html – iwasrobbed 2013-02-04 14:08:37

如果您有NSDate，則可以使用當前的NSCalendar檢索該日期的NSDateComponents。將NSDateComponents的weekday設置爲1（一週的第一天），創建副本，並將副本的weekday設置爲7（一週的最後一天）。然後使用NSCalendar將兩個NSDateComponents轉換回它們各自的NSDate對象，之後您可以使用NSDateFormatter創建字符串表示。

此鏈接有關於如何得到一個日期的工作日爲例：https://stackoverflow.com/questions/1057349#1057405

來源

2010-01-17 20:53:20

什麼如果這一週跨越一個月的結束和下一個的開始？ – 2012-10-17 03:01:38

@jeffamaphone'NSCalendar'由'NSDateComponents'轉換爲'NSDate'將處理任何月份轉換。如果您遇到麻煩，請隨時發佈新問題，讓我知道，我會回答。 – 2012-10-17 03:04:42

啊，好的。我現在看到，「週日」不是日期，而是一週中的序號。現在更有意義。 :) – 2012-10-17 03:06:29

下面是一些代碼，並在本週初前一個月開始它還會檢查邊界情況：

// Finds the date for the first day of the week 
- (NSDate *)getFirstDayOfTheWeekFromDate:(NSDate *)givenDate 
{ 
    NSCalendar *calendar = [NSCalendar currentCalendar]; 

    // Edge case where beginning of week starts in the prior month 
    NSDateComponents *edgeCase = [[NSDateComponents alloc] init]; 
    [edgeCase setMonth:2]; 
    [edgeCase setDay:1]; 
    [edgeCase setYear:2013]; 
    NSDate *edgeCaseDate = [calendar dateFromComponents:edgeCase]; 

    NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:edgeCaseDate]; 
    [components setWeekday:1]; // 1 == Sunday, 7 == Saturday 
    [components setWeek:[components week]]; 

    NSLog(@"Edge case date is %@ and beginning of that week is %@", edgeCaseDate , [calendar dateFromComponents:components]); 

    // Find Sunday for the given date 
    components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate]; 
    [components setWeekday:1]; // 1 == Sunday, 7 == Saturday 
    [components setWeek:[components week]]; 

    NSLog(@"Original date is %@ and beginning of week is %@", givenDate , [calendar dateFromComponents:components]); 

    return [calendar dateFromComponents:components]; 
}

編輯：從上面

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

    NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate]; 
    [components setWeekday:1]; // 1 == Sunday, 7 == Saturday 
    [components setWeekOfYear:[components weekOfYear]]; 

    return [calendar dateFromComponents:components]; 
}

來源

2013-02-04 14:22:22 iwasrobbed

相關的代碼這是我以前找天終於找到了。在NSDate中有一種方法rangeOfUnit:startDate:interval:forDate:，並以簡單的方式執行該操作。 Current Week Start and End Date

來源

2013-05-06 05:28:10

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 EEEE"; 
NSString *firstStr = [myDateFormatter stringFromDate:firstDayOfTheWeek]; 
NSString *secondStr = [myDateFormatter stringFromDate:lastDayOfTheWeek]; 

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

來源

2014-04-11 12:10:35 Anupama

計算當前周的第一天和最後一天

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