ios - 如何显示与当前日期相比的时差？

Question

我有一个 createdAt 时间戳。该 createdAt 时间戳将与当前日期 (Date()) 进行比较。

假设当前日期是 2018 年 8 月 1 日。如果创建时间是 2018 年 7 月 28 日，则只显示 2018 年 7 月 28 日。但如果创建时间是同一天(2018 年 8 月 1 日)，则只显示 2 米前，5 小时 38 分15 年前，类似这样的事情，比如这个:

我尝试使用下面的代码，但结果不一致。如果日期不同但下面的代码仍然显示 5h 16m。

func calculateTimeDifference() -> String? {
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    dateFormatter.locale = Locale(identifier: "en_US_POSIX")

    guard let date1 = dateFormatter.date(from: dateTimeString) else {
        return nil
    }

    let date2 = Date()

    let components : Set<Calendar.Component> = [.second, .minute, .hour, .day, .month, .year]
    let difference = Calendar.current.dateComponents(components, from: date1, to: date2)

    var dateTimeDifferenceString = ""

    var secondDifference = ""
    var minuteDifference = ""
    var hourDifference = ""
    var dayDifference = ""

    if difference.second! < 0 {
        secondDifference = "0"
    } else {
        secondDifference = String(difference.second!)
    }

    if difference.minute! < 0 {
        minuteDifference = "0"
    } else {
        minuteDifference = String(difference.minute!)
    }

    if difference.hour! < 0 {
        hourDifference = "0"
    } else {
        hourDifference = String(difference.hour!)
    }

    if difference.day! < 0 {
        dayDifference = "0"
    } else{
        dayDifference = String(difference.day!)
    }


    if difference.minute! == 0 {
        dateTimeDifferenceString = "\(secondDifference)s"
    } else if difference.hour == 0 {
        dateTimeDifferenceString = "\(minuteDifference)m"
    } else if difference.day == 0 {
        dateTimeDifferenceString = "\(hourDifference)h \(minuteDifference)m"
    } else if  difference.day! > 0 {
        dateTimeDifferenceString = "different day \(dayDifference)"
    }

    return dateTimeDifferenceString
}

能否请您分享您的代码？

Answer 1

就我个人而言，我会使用 DateComponentsFormatter，这是比尝试按时执行数学运算更安全的选择，这绝不是一个好主意

let duration = Date().timeIntervalSince(date1)
let formatter = DateComponentsFormatter()
formatter.unitsStyle = .abbreviated
formatter.allowedUnits = [ .day, .hour, .minute, .second]

let durationFormat = formatter.string(from: duration)

看看Formatting a Duration with NSDateComponentsFormatter了解更多详情。