Question

有没有人知道是否有办法在NSCalendar上设置一周的第一天，或者是否有一个日历已经将星期一作为一周的第一天而不是星期日。我目前正在开发一款基于一周工作量的应用程序，它需要在星期一而不是星期天开始。我很可能会做一些工作来解决这个问题，但会有很多极端情况。我更喜欢平台为我做这件事。

提前致谢

这是我正在使用的一些代码。现在是星期六，所以我希望工作日是6，而不是7，这意味着星期日将是7而不是滚动到0

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setFirstWeekday:0];
unsigned unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit | NSWeekCalendarUnit | NSWeekdayCalendarUnit;
NSDateComponents *todaysDate = [gregorian components:unitFlags fromDate:[NSDate date]];
int dayOfWeek = todaysDate.weekday;

Answer 1

编辑：这不会检查上周开始的一周开始的边缘情况。一些更新的代码涵盖了这一点：https://stackoverflow.com/a/14688780/308315

如果有人仍在关注此事，您需要使用

ordinalityOfUnit:inUnit:forDate:

并将firstWeekday设为2.（1 == Sunday和7 == Saturday）

以下是代码：

NSCalendar *gregorian = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
[gregorian setFirstWeekday:2]; // Sunday == 1, Saturday == 7
NSUInteger adjustedWeekdayOrdinal = [gregorian ordinalityOfUnit:NSWeekdayCalendarUnit inUnit:NSWeekCalendarUnit forDate:[NSDate date]];
NSLog(@"Adjusted weekday ordinal: %d", adjustedWeekdayOrdinal);

请记住，工作日的序数从一周的第一天开始，而不是零。

Documentation link

Answer 2

此代码构造一个设置为当前星期一的日期：

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDate *today = [NSDate date];
NSDate *beginningOfWeek = nil;
BOOL ok = [gregorian rangeOfUnit:NSWeekCalendarUnit startDate:&beginningOfWeek
                                interval:NULL forDate: today];

Answer 3

NSCalendar对象上的

setFirstWeekday：。设置接收者的第一个工作日的索引。

- (void)setFirstWeekday:(NSUInteger)weekday

应该做的伎俩。

Answer 4

在我看来，根据用户区域设置，此设置应该是动态的。因此，应该使用：

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[gregorian setLocale:[NSLocale currentLocale]];

这将使日历根据用户区域设置自动设置第一周。除非您为特定目的/用户区域设置开发应用程序（或者更愿意让用户选择这一天）。

Answer 5

我这样做了。

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *today = [NSDate date];
NSDateComponents *compForWeekday = [gregorian components:(NSWeekdayCalendarUnit) fromDate:today];
NSInteger weekDayAsNumber = [compForWeekday weekday]; // The week day as number but with sunday starting as 1

weekDayAsNumber = ((weekDayAsNumber + 5) % 7) + 1; // Transforming so that monday = 1 and sunday = 7

Answer 6

我在这里遇到了很多答案。。也许只是我。。

这是一个适合我的答案：

- (NSDate*)firstDayOfWeek
{
    NSCalendar* cal = [[NSCalendar currentCalendar] copy];
    [cal setFirstWeekday:2]; //Override locale to make week start on Monday
    NSDate* startOfTheWeek;
    NSTimeInterval interval;
    [cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
    return startOfTheWeek;
}

- (NSDate*)lastDayOfWeek
{
    NSCalendar* cal = [[NSCalendar currentCalendar] copy];
    [cal setFirstWeekday:2]; //Override locale to make week start on Monday
    NSDate* startOfTheWeek;
    NSTimeInterval interval;
    [cal rangeOfUnit:NSWeekCalendarUnit startDate:&startOfTheWeek interval:&interval forDate:self];
    return [startOfTheWeek dateByAddingTimeInterval:interval - 1];
}

<强>更新

正如@vikingosegundo指出的那样（elsewhere），一般来说最好让当地人决定哪一天是本周的开始，但是在这种情况下，OP要求本周开始星期一发生，因此我们复制系统日历，并覆盖firstWeekDay。

Answer 7

Kris回答的问题是本周初在上个月开始的边缘情况。这是一些更简单的代码，它还检查边缘情况：

// 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];
}

Answer 8

我看到其他消息中的误解。第一个工作日，以它为准，数字1不为0.默认星期日= 1，如“可可日期和时间编程指南简介：日历计算”：

“格里高利历中星期日的工作日值为1”

对于星期一作为第一个工作日，我唯一的补救措施是强力条件来解决计算

NSCalendar *cal=[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *comps = [cal components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
// set to 7 if it's Sunday otherwise decrease weekday number
NSInteger weekday=[comps weekday]==1?7:[comps weekday]-1;

Answer 9

下面还介绍了边缘情况，

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


   NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSWeekCalendarUnit|NSWeekdayCalendarUnit fromDate:givenDate];
    [components setWeekday:2]; // 1 == Sunday, 7 == Saturday
    if([[calendar dateFromComponents:components] compare: curDate] == NSOrderedDescending) // if start is later in time than end
    {
        [components setWeek:[components week]-1];
    }

    return [calendar dateFromComponents:components];
}

Answer 10

Swift解决方案（请注意，使用 .yearForWeekOfYear ，而不是.year）：

let now = Date()
let cal = Calendar.current
var weekComponents = cal.dateComponents([.yearForWeekOfYear, .weekOfYear,
                                         .weekday], from: now)
//weekComponents.weekday = 1  // if your week starts on Sunday
weekComponents.weekday = 2  // if your week starts on Monday
cal.date(from: weekComponents) // returns date with first day of the week

Answer 11

您只需更改日历的.firstWeekday即可。

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
calendar.firstWeekday = 2;

然后使用rangeOfUnit:startDate:interval:forDate:获取第一天

NSDate *startOfWeek;
[calendar rangeOfUnit:NSCalendarUnitWeekOfYear startDate:&startOfWeek interval:nil forDate:[NSdate date]];

Answer 12

使用日历nextWeekend（iOS 10或更高版本）和ordinality（感谢@ kris-markel）。我已经在星期一作为en_US日历的第一周了。

以下是回溯至firstWeekday的示例：

extension Calendar {
    var firstWorkWeekday: Int {
        guard #available(iOS 10.0, *) else{
            return self.firstWeekday
        }
        guard let endOfWeekend = self.nextWeekend(startingAfter: Date())?.end else {
            return self.firstWeekday
        }
        return self.ordinality(of: .weekday, in: .weekOfYear, for: endOfWeekend) ?? self.firstWeekday
    }
}

Answer 13

ISO 8601日历似乎默认情况下将其第一个工作日设置为星期一。

Answer 14

我这样做的简单方法是让星期一= 0，星期日= 6：

    NSDateComponents *dateComponents = [[NSCalendar currentCalendar] components:NSWeekdayCalendarUnit fromDate:[NSDate date]];
    NSInteger dayNumStartingFromMonday = ([dateComponents weekday] - 2 + 7) % 7;    //normal: Sunday is 1, Monday is 2

Answer 15

我发现使用nscalender显示任何工作日名称的方式..使用以下代码.. 只需从xcode菜单栏打开控制台即可查看结果。复制在viewDidLoad方法中粘贴以下代码以获取一周的第一天

NSDate *today = [NSDate date];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"MM/dd/yyyy :EEEE"];
NSString *dateString = [dateFormat stringFromDate:today];
NSLog(@"date: %@", dateString);
[dateFormat release];
NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *components = [gregorian components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:today];
[components setDay:([components day]-([components weekday]-1))];

NSDate *beginningOfWeek = [gregorian dateFromComponents:components];
NSDateFormatter *dateFormat_first = [[NSDateFormatter alloc] init];
[dateFormat_first setDateFormat:@"MM/dd/yyyy :EEEE"];
NSString *dateString_first = [dateFormat_first stringFromDate:beginningOfWeek];
NSLog(@"First_date: %@", dateString_first);

输出将是：

 date: 02/11/2010 :Thursday
 First_date: 02/07/2010 :Sunday

因为我在2010年11月2日运行了这个程序，你将根据当前日期获得所需的输出。

同样，如果你想获得一周的第一个工作日，即周一的日期，那么只需修改一下代码：

更改：[components setDay:([components day]-([components weekday]-1))];

要 [components setDay:([components day]-([components weekday]-2))];

获取周一的星期日..

同样，您可以通过更改整数-1，-2等来尝试查找七个工作日中任何一个的日期......

希望你的问题得到解答..

谢谢， Bonson Dias

Answer 16

试试这个：

NSCalendar *yourCal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar]
[yourCal setFirstWeekday:0];

Answer 17

...是否有一个日历已经是星期一作为一周的第一天，而不是星期日。

Someday, there will be.

NSCalendar第一天的第一天

17 个答案: