7

我正在尝试获取当年的天数。

当我使用 iPhone SDK 在当月的天数上尝试解决方案时？，并用 NSYearCalendarUnit 替换 NSMonthCalendarUnit，我仍然得到该月的天数。

有谁知道我应该怎么做？

在此先感谢您的帮助。

4

5 回答 5

8

NSCalendar这是Swift 2 中的一个超级准确的扩展：

extension NSCalendar {
    func daysInYear(date: NSDate = NSDate()) -> Int? {
        let year = components([NSCalendarUnit.Year], fromDate: date).year
        return daysInYear(year)
    }

    func daysInYear(year: Int) -> Int? {
        guard let begin = lastDayOfYear(year - 1), end = lastDayOfYear(year) else { return nil }
        return components([NSCalendarUnit.Day], fromDate: begin, toDate: end, options: []).day
    }

    func lastDayOfYear(year: Int) -> NSDate? {
        let components = NSDateComponents()
        components.year = year
        guard let years = dateFromComponents(components) else { return nil }

        components.month = rangeOfUnit(NSCalendarUnit.Month, inUnit: NSCalendarUnit.Year, forDate: years).length
        guard let months = dateFromComponents(components) else { return nil }

        components.day = rangeOfUnit(NSCalendarUnit.Day, inUnit: NSCalendarUnit.Month, forDate: months).length

        return dateFromComponents(components)
    }
}

你可以像这样使用它：

let calendar = NSCalendar.currentCalendar() // I'm using the Gregorian calendar
calendar.daysInYear()     // 365 (since it's currently 2015)
calendar.daysInYear(2016) // 366 (leap year!)

这是超级灵活的，因为我们不假设日历的长度：

let hebrew = NSCalendar(calendarIdentifier: NSCalendarIdentifierHebrew)
hebrew?.daysInYear(-7)   // 354
hebrew?.daysInYear(-100) // 384

享受。

于 2015-08-14T07:25:21.853 回答
5

我终于想出了一个可行的解决方案。我所做的是首先计算一年中的月数，然后每个月计算该月的天数。

代码如下所示：

NSUInteger days = 0;
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *today = [NSDate date];
NSDateComponents *components = [calendar components:NSYearCalendarUnit fromDate:today];
NSUInteger months = [calendar rangeOfUnit:NSMonthCalendarUnit
                                   inUnit:NSYearCalendarUnit
                                  forDate:today].length;
for (int i = 1; i <= months; i++) {
    components.month = i;
    NSDate *month = [calendar dateFromComponents:components];
    days += [calendar rangeOfUnit:NSDayCalendarUnit
                           inUnit:NSMonthCalendarUnit
                          forDate:month].length;
}

return days;

它不像我希望的那样整洁，但它适用于任何日历，例如普通的公历日历或伊斯兰日历。

于 2010-01-16T19:14:13.833 回答
5

如果您只打算使用公历，您可以手动计算。

http://en.wikipedia.org/wiki/Leap_year#Algorithm

if year modulo 400 is 0 then leap
 else if year modulo 100 is 0 then no_leap
 else if year modulo 4 is 0 then leap
 else no_leap
于 2009-09-24T15:31:40.513 回答
1

使用NSCalendar和NSDateComponent类，如下所示：

long GetDaysInYear(int year) {
    NSDateComponents* c = [[NSDateComponents alloc] init];
    c.year = year;
    NSCalendar* cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
    NSDate* startDate = [cal dateFromComponents:c];
    c.year += 1;
    NSDate* endDate = [cal dateFromComponents:c];
    return [cal components:NSDayCalendarUnit fromDate:startDate toDate:endDate options:0].day;
}
于 2013-06-30T08:02:30.393 回答
0

例如：

func daysInYear(year: Int) -> Int {
   var calendar = NSCalendar(calendarIdentifier: NSGregorianCalendar)
   var b = NSDate.dateWithNaturalLanguageString("01.01.\(year)", locale: NSLocale.currentLocale()) as! NSDate
   var e = NSDate.dateWithNaturalLanguageString("12.31.\(year)", locale: NSLocale.currentLocale()) as! NSDate

   return calendar!.components(NSCalendarUnit.CalendarUnitDay, fromDate: b, toDate: e, options: nil).day + 1 
}

但是默认天数返回 355 和 354 这导致（可能是）计数从零开始:)

于 2015-04-20T11:52:39.520 回答