Question

我想计算2个日期之间的时差，时差结果必须类似

7h 12m OR 4 d 5h 27m OR 1M 5d 3h 21m

我试过写一个这样的函数：

import UIKit

func calculateTimeDifference(from dateTime1: String, to dateTime2: String) -> String {

    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

    let dateAsString = dateTime1
    let date1 = dateFormatter.date(from: dateAsString)!

    let dateAsString2 = dateTime2
    let date2 = dateFormatter.date(from: dateAsString2)!

    let components : NSCalendar.Unit = [.second, .minute, .hour, .day, .weekOfMonth, .month, .year]
    let difference = (Calendar.current as NSCalendar).components(components, from: date1, to: date2, options: [])

    var dateTimeDifferenceString = ""

    if difference.day != 0 {
        dateTimeDifferenceString = "\(difference.day!)d \(difference.hour!)h \(difference.minute!)m"
    } else if  difference.day == 0 {
        dateTimeDifferenceString = "\(difference.hour!)h \(difference.minute!)m"
    }

    return dateTimeDifferenceString
}

但是当我实现这段代码时

let checkinTime = "2018-02-09 07:51:01"
let now = "2018-02-20 14:56:18"

calculateTimeDifference(from: checkinTime, to: now) 

// Result: "4d 7h 5m"

我不知道为什么只有4天而不是11天

但是如果我在同一天实施它，它会给出正确的结果

let checkinTime = "2018-02-09 07:51:01"
let now = "2018-02-09 14:56:18"

calculateTimeDifference(from: checkinTime, to: now)
// "7h 5m"

这里出了什么问题？

Answer 1

在第一种情况下，日期之间的差异是一周而且四天，您将看到如果您打印计算的日期组件。

print(difference)
// year: 0 month: 0 day: 4 hour: 7 minute: 5 second: 17 weekOfMonth: 1 isLeapMonth: false
//                  ^^^^^^                              ^^^^^^^^^^^^^^

这就是为什么你得到输出＆＃34; 4d 7h 5m＆＃34;而不是预期＆＃34; 11d 7h 5m＆＃34;。要解决此问题，只需删除.weekOfMonth 来自日历单位：

let components : NSCalendar.Unit = [.second, .minute, .hour, .day, .month, .year]

此外，您可以直接使用Calendar，而无需使用NSCalendar 桥接到let components: Set<Calendar.Component> = [.second, .minute, .hour, .day, .month, .year] let difference = Calendar.current.dateComponents(components, from: date1, to: date2)：

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Answer 2

请找到有效的解决方案：

    func calculateTimeDifference(from dateTime1: String, to dateTime2: String) -> String {
                   let dateFormatter = DateFormatter()
                   dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
                            
                   let dateAsString = dateTime1
                   let date1 = dateFormatter.date(from: dateAsString)!
                            
                   let dateAsString2 = dateTime2
                   let date2 = dateFormatter.date(from: dateAsString2)!
                            
                   let components : NSCalendar.Unit = [.second, .minute, .hour, .day,.month, .year]
                   let difference = (Calendar.current as NSCalendar).components(components, from: date1, to: date2, options: [])
                            
                   var dateTimeDifferenceString = ""
                            
                   if difference.day != 0 {
                               dateTimeDifferenceString = "\(difference.day!)d \(difference.hour!)h \(difference.minute!)m"
                       } else if  difference.day == 0 {
                               dateTimeDifferenceString = "\(difference.hour!)h \(difference.minute!)m"
                       }
                            
                   return dateTimeDifferenceString
                            
           }

使用以下代码调用此函数：

让checkinTime =“2018-02-09 07:51:01”

现在=“2018-02-20 14:56:18”

self.calculateTimeDifference（from：checkinTime，to：now）

所以你会得到确切的差异日期。

如何在Swift中正确计算日期时差

2 个答案: