如何基于给定的NSDate生成方便的日期范围？ [英] How can I generate convenient date ranges based on a given NSDate?

问题描述

我在Cocoa中创建了一个报表生成器，我需要生成方便的日期范围，例如今天，本周，本月，今年等。

有没有好的方法来做到这一点？这是我的骨架到目前为止：

  @interface DateRange：NSObject 
 {
 NSDate startDate; 
 NSDate endDate; 
} 
 
 @property（nonatomic，retain）NSDate * startDate; 
 @property（nonatomic，retain）NSDate * endDate; 
 
 +（DateRange *）rangeForDayContainingDate：（NSDate *）date; 
 +（DateRange *）rangeForWeekContainingDate：（NSDate *）date; 
 +（DateRange *）rangeForMonthContainingDate：（NSDate *）date; 
 +（DateRange *）rangeForYearContainingDate：（NSDate *）date; 
 
 @end 
  

一些示例用例如下： p>

  DateRange * thisWeek = [DateRange rangeForWeekContainingDate：[NSDate date]]; 
 DateRange * thisYear = [DateRange rangeForYearContainingDate：[NSDate date]]; 
  

基本上，我想要返回的 DateRange 对象以包含围绕目标日期的周，月或年的开始和结束日期。例如（以伪代码）：

  NSDate * today = [2009年8月25日] 
 DateRange * thisWeek = [DateRange rangeForWeekContainingDate：today]; 
 assert（thisWeek.startDate == [August 23，3009]）; 
 assert（thisWeek.endDate == [August 29，3009]）; 
   
 
 
 
 更新：
 
 
 
我能够通过由Kendall Helmstetter Geln提供的答案。以下是一周范围的完整方法：
  +（DateRange *）rangeForWeekContainingDate：（NSDate *）date 
 {
 DateRange * range = [[self alloc] init]; 
 
 //星期开始
 NSDate * firstDay; 
 [[self calendar] rangeOfUnit：NSWeekCalendarUnit 
 startDate：& firstDay 
 interval：0 
 forDate：date]; 
 [range setStartDate：firstDay]; 
 
 //周末结束
 NSDateComponents * oneWeek = [[NSDateComponents alloc] init]; 
 [oneWeek setWeek：1]; 
 [range setEndDate：[[self calendar] dateByAddingComponents：oneWeek 
 toDate：firstDay 
 options：0]]; 
 [oneWeek release]; 
 
 return [range autorelease]; 
} 
  
 
 
解决方案
 ，只需要计算一天中的秒数：
 
 
 
 60秒* 60分钟* 24小时= 1天。
 
 
 
然后在 rangeForDayContainingDate 方法中，您可以提取日期组件，获取当前日期，基于设置小时和分钟的日期创建新日期到0:00，并创建结束日期，添加上面计算的时间间隔。
 
I'm creating a report generator in Cocoa, and I need to produce convenient date ranges such as "Today", "This Week", "This Month", "This Year", etc.

Is there a good way to do this? Here is my skeleton thus far:
@interface DateRange : NSObject
{
    NSDate startDate;
    NSDate endDate;
}

@property (nonatomic, retain) NSDate * startDate;
@property (nonatomic, retain) NSDate * endDate;

+ (DateRange *)rangeForDayContainingDate:(NSDate *)date;
+ (DateRange *)rangeForWeekContainingDate:(NSDate *)date;
+ (DateRange *)rangeForMonthContainingDate:(NSDate *)date;
+ (DateRange *)rangeForYearContainingDate:(NSDate *)date;

@end
Some example use cases would be as follows:
DateRange * thisWeek = [DateRange rangeForWeekContainingDate:[NSDate date]];
DateRange * thisYear = [DateRange rangeForYearContainingDate:[NSDate date]];
Essentially, I want the returned DateRange object to contain the start and end dates for the week, month or year surrounding the target date. For example (in pseudocode):
NSDate * today = [August 25, 2009];
DateRange * thisWeek = [DateRange rangeForWeekContainingDate:today];
assert(thisWeek.startDate == [August 23, 3009]);
assert(thisWeek.endDate == [August 29, 3009]);
update:

I was able to get this working thanks to the answer provided by Kendall Helmstetter Geln. Here is the complete method for a one-week range:
+ (DateRange *)rangeForWeekContainingDate:(NSDate *)date
{
    DateRange * range = [[self alloc] init];

    // start of the week
    NSDate * firstDay;
    [[self calendar] rangeOfUnit:NSWeekCalendarUnit
                       startDate:&firstDay
                        interval:0
                         forDate:date];
    [range setStartDate:firstDay];

    // end of the week
    NSDateComponents * oneWeek = [[NSDateComponents alloc] init];
    [oneWeek setWeek:1];
    [range setEndDate:[[self calendar] dateByAddingComponents:oneWeek
                                                       toDate:firstDay
                                                      options:0]];
    [oneWeek release];

    return [range autorelease];
}

解决方案
Well since timeInterval is in seconds, just do the math to figure out how many seconds are in a day:

60 seconds * 60 minutes * 24 hours = 1 day.

Then in your rangeForDayContainingDate method you could extract date components, get the current day, create a new date based on the day with hours and minutes set to 0:00, and the create the end date adding the time interval as calculated above.

                        
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