计算2个快速日期对象之间的百分比

Question

我有一个带有计时器的应用

我有2个参数(例如(：

creationDate：2018-02-16 17:06:10 UTC'端'：2018-02-16 15:07:09 UTC

计时器应显示2 Dates。

之间的百分比

我尝试过：

let duration = self.creationDate.timeIntervalSince(self.endDate)
let timePassed = self.creationDate.timeIntervalSinceNow
let percent = (timePassed * 100) / duration

但是我得到的信息不正确。

有人知道我的算法怎么了？谢谢！

Answer 1

您的参考日期是StartDate而不是终结：

let duration = self.endDate.timeIntervalSince(self.creationDate)
let timePassed = Date().timeIntervalSince(self.creationDate)
let percent = (duration - timePassed) / duration * 100

Answer 2

我希望这会有所帮助(我重命名为示例中的创建/结束变量以使答案更清晰(

let initialDate = Date().addingTimeInterval(-1000)
let now = Date()
let finalDate = Date().addingTimeInterval(10000)
let totalDuration = finalDate.timeIntervalSince(initialDate)
let currentRemainingDuration = finalDate.timeIntervalSince(now)
let percent = (currentRemainingDuration/totalDuration) * 100

另外，请注意，在您的示例中，日期结束日期是在创建日期之前。

Answer 3

当我不得不写这样的东西时，我更喜欢变得更加愚蠢，plod脚和系统性。这是一个示威。我们将计算上一个生日和下一个生日之间的距离：

// initial conditions
let greg = Calendar(identifier: .gregorian)
let dc1 = DateComponents(calendar: greg, year: 2017, month: 8, day: 10)
let dc2 = DateComponents(calendar: greg, year: 2018, month: 8, day: 10)
let dstart = greg.date(from: dc1)!
let dend = greg.date(from: dc2)!
let target = Date() // now
// okay, ready to go! convert all dates to time intervals
let dend_ti = dend.timeIntervalSince(dstart)
let target_ti = target.timeIntervalSince(dstart)
// target is what percentage of dend?
let x = target_ti * 100 / dend_ti
// clamp between 0 and 100
let result = min(max(x, 0), 100)
// print result nicely
print(Int(result), "%", separator:"") // 52%

注意"夹具"步骤；这将消除您的局外结果。