ios - 将 TimeInterval 转换为字符串 String To Time Interval

Question

我有一个 TimeInterval 我必须将它变成一个 String 以便它可以添加到从 Apple Watch 传递的 Dictionary通过 WatchConnectivity 连接到 iPhone。

现在我在 iPhone 上有了 String，我需要把它变回 TimeInterval，但我似乎不能弄清楚这一点。

(我需要在显示锻炼持续时间的 UILabel 中显示它。)

有什么想法吗？

例如

观看:

00:15:15(时、分、秒)变成“915.012948989868”

let myDouble = computeDurationOfWorkout(withEvents: hkWorkout?.workoutEvents, startDate: hkWorkout?.startDate, endDate: hkWorkout?.endDate)
let myDoubleString = String(myDouble)
durationVariableString = myDoubleString 

iPhone:

需要将“915.012948989868”转回00:15:15

Answer 1

使用 calendar.dateComponents 可以将 915 转换为 00:15:15

func stringFromTimeInterval (interval: String) -> String {
        let endingDate = Date()
        if let timeInterval = TimeInterval(interval) {
            let startingDate = endingDate.addingTimeInterval(-timeInterval)
            let calendar = Calendar.current

            var componentsNow = calendar.dateComponents([.hour, .minute, .second], from: startingDate, to: endingDate)
            if let hour = componentsNow.hour, let minute = componentsNow.minute, let seconds = componentsNow.second {
                return "\(hour):\(minute):\(seconds)"
            } else {
                return "00:00:00"
            }

        } else {
            return "00:00:00"
        }
    }