目的计算两个日期之间的天数

Possible Duplicate:
How can I compare two dates, return a number of days.

可能重复:如何比较两个日期，返回天数。

I have two dates (as NSString in the form "yyyy-mm-dd"), for example:

我有两个日期(如“yyyy-mm-dd”格式的NSString)，例如:

NSString *start = "2010-11-01";
NSString *end = "2010-12-01";

I'd like to implement:

我想实现:

- (int)numberOfDaysBetween:(NSString *)startDate and:(NSString *)endDate {

}

Thanks!

谢谢!

6 个解决方案

#1

NSString *start = @"2010-09-01";
NSString *end = @"2010-12-01";

NSDateFormatter *f = [[NSDateFormatter alloc] init];
[f setDateFormat:@"yyyy-MM-dd"];
NSDate *startDate = [f dateFromString:start];
NSDate *endDate = [f dateFromString:end];

NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
NSDateComponents *components = [gregorianCalendar components:NSCalendarUnitDay
                                                    fromDate:startDate
                                                      toDate:endDate
                                                     options:0];

components now holds the difference.

组件现在具有差异。

NSLog(@"%ld", [components day]);

#2

There is a whole guide to Date and Time Programming. Here is a relevant section which gives you a hint about what to do.

有一个关于日期和时间编程的完整指南。这里是一个相关的部分，它给你一个提示，告诉你该做什么。

It's where the example code comes from in the other question.

这就是示例代码来自另一个问题的地方。

Try and write something based on that and then come back if you have specific questions.

在此基础上写点东西，如果有什么问题，可以回来问。

Edit

编辑

Okay. Here is how I would write the code in it's most basic form.

好吧。下面是我如何用它最基本的形式来编写代码。

First, I would extend NSDate.

首先，我将扩展NSDate。

The header file:

头文件:

//  NSDate+ADNExtensions.h

#import <Cocoa/Cocoa.h>


@interface NSDate (ADNExtensions)

- (NSInteger)numberOfDaysUntil:(NSDate *)aDate;

@end

The implementation file:

实现文件:

//  NSDate+ADNExtensions.m

#import "NSDate+ADNExtensions.h"


@implementation NSDate (ADNExtensions)


- (NSInteger)numberOfDaysUntil:(NSDate *)aDate {
    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDateComponents *components = [gregorianCalendar components:NSDayCalendarUnit fromDate:self toDate:aDate options:0];

    return [components day];
}


@end

This is very rough code. There is no error checking or validating that the second date is later than the first.

这是非常粗略的代码。没有错误检查或验证第二个日期比第一个日期晚。

And then I would use it like this (running on a 64-bit, Garbage Collected environment):

然后像这样使用它(在64位的垃圾收集环境中运行):

NSDate *startDate = [NSDate dateWithString:@"2010-11-01 00:00:00 +0000"];
NSDate *endDate = [NSDate dateWithString:@"2010-11-02 00:00:00 +0000"];

NSInteger difference = [startDate numberOfDaysUntil:endDate];

NSLog(@"Diff = %ld", difference);

This is such a shame, because you would have learned a lot more by posting your code and the incorrect outputs and getting more specific help. But if you just want to be a cut-and-paste programmer; take this code and good luck to you.

这真是太遗憾了，因为如果你发布你的代码和错误的输出并得到更多的帮助，你会学到更多。但是如果你只是想成为一个剪切粘贴的程序员;带上这个密码，祝你好运。

#3

This code seems to work nicely in Swift 2:

这段代码在Swift 2中似乎运行得很好:

func daysBetweenDate(startDate: NSDate, endDate: NSDate) -> Int
{
    let calendar = NSCalendar.currentCalendar()

    let components = calendar.components([.Day], fromDate: startDate, toDate: endDate, options: [])

    return components.day
}

#4

ObjC Code:

ObjC代码:

NSDateComponents *dateComponent = [calender components:NSCalendarUnitDay fromDate:startDate toDate:endDate options:0];

Result:

结果:

int totalDays = (int)dateComponent.day;

#5

Swift 3:

斯威夫特3:

let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd"
let start = formatter.date(from: "2010-09-01")!
let end = formatter.date(from: "2010-12-01")!
let days = Calendar.current.dateComponents([.day], from: start, to: end).day!

#6

Swift 4 implementation

斯威夫特4实现

Method call :

方法调用:

let numberOfDays = daysBetweenDates(startDate: fileCreatedDate,endDate: date)

Method Implementation:

方法实现:

 func daysBetweenDates(startDate: Date, endDate: Date) -> Int {
        let daysBetween = Calendar.current.dateComponents([.day], from: startDate, to: endDate)
        print(daysBetween.day!)
        return daysBetween.day!
  }

Objective C implementation:

Objective - C实现:

Method Call:

方法调用:

int numberOfDaysSinceFileCreation = [self daysBetweenDates: fileCreatedDate
                                                                   currentDate: today];

Method Implementation:

方法实现:

- (int) daysBetweenDates: (NSDate *)startDate currentDate: (NSDate *)endDate
{
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *dateComponent = [calendar components:NSCalendarUnitDay fromDate:startDate toDate:endDate options:0];

    int totalDays = (int)dateComponent.day;
    return totalDays;

}