如何计算目标C中今年的天数 [英] How do I calculate the number of days in this year in Objective C

问题描述

如何计算任何日历的一年中的天数，而不仅仅是格里高利。
我试过这个

How can i calculate the number of days in a year for any calendar, not just gregorian. I have tried this

NSUInteger * days = [[NSCalendar currentCalendar] rangeOfUnit：NSDayCalendarUnit inUnit：NSYearCalendarUnit forDate：[NSDate date] ];

但是这给了我当月的天数而不是当年的天数。

but that gives me the number of days in the current month instead of the number of days in the current year.

推荐答案

我终于想出了一个有效的解决方案。我所做的是首先计算一年中的月数，然后计算每个月的月数。

I finally came up with a solution that works. What I do is first calculate the number of months in the year and then for each month calculate the number of days for that month.

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，例如普通的格里高利人或伊斯兰人。

It is not as neat as I would have hoped for but it will work for any calendar such as the ordinary gregorian one or the islamic one.

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