@r3dm4n的回答很棒。然而，我也需要一个小时。以防别人也需要，这里是:

func formatSecondsToString(_ seconds: TimeInterval) -> String {
    if seconds.isNaN {
        return "00:00:00"
    }
    let sec = Int(seconds.truncatingRemainder(dividingBy: 60))
    let min = Int(seconds.truncatingRemainder(dividingBy: 3600) / 60)
    let hour = Int(seconds / 3600)
    return String(format: "%02d:%02d:%02d", hour, min, sec)
}

我已经回答了类似的问题，但是你不需要在结果中显示毫秒。因此，我的解决方案需要iOS 10.0, tvOS 10.0, watchOS 3.0或macOS 10.12。

你应该调用func convertDurationUnitValueToOtherUnits(durationValue:durationUnit: smallstunitduration:)从我已经在这里提到的答案:

let secondsToConvert = 27005
let result: [Int] = convertDurationUnitValueToOtherUnits(
    durationValue: Double(secondsToConvert),
    durationUnit: .seconds,
    smallestUnitDuration: .seconds
)
print("\(result[0]) hours, \(result[1]) minutes, \(result[2]) seconds") // 7 hours, 30 minutes, 5 seconds

基于Vadian的回答，我写了一个扩展，它接受Double(其中TimeInterval是类型别名)，并输出一个格式化为时间的字符串。

extension Double {
  func asString(style: DateComponentsFormatter.UnitsStyle) -> String {
    let formatter = DateComponentsFormatter()
    formatter.allowedUnits = [.hour, .minute, .second, .nanosecond]
    formatter.unitsStyle = style
    return formatter.string(from: self) ?? ""
  }
}

这里是各种DateComponentsFormatter。UnitsStyle选项看起来像这样:

10000.asString(style: .positional)  // 2:46:40
10000.asString(style: .abbreviated) // 2h 46m 40s
10000.asString(style: .short)       // 2 hr, 46 min, 40 sec
10000.asString(style: .full)        // 2 hours, 46 minutes, 40 seconds
10000.asString(style: .spellOut)    // two hours, forty-six minutes, forty seconds
10000.asString(style: .brief)       // 2hr 46min 40sec

我正在使用这个扩展

 extension Double {

    func stringFromInterval() -> String {

        let timeInterval = Int(self)

        let millisecondsInt = Int((self.truncatingRemainder(dividingBy: 1)) * 1000)
        let secondsInt = timeInterval % 60
        let minutesInt = (timeInterval / 60) % 60
        let hoursInt = (timeInterval / 3600) % 24
        let daysInt = timeInterval / 86400

        let milliseconds = "\(millisecondsInt)ms"
        let seconds = "\(secondsInt)s" + " " + milliseconds
        let minutes = "\(minutesInt)m" + " " + seconds
        let hours = "\(hoursInt)h" + " " + minutes
        let days = "\(daysInt)d" + " " + hours

        if daysInt          > 0 { return days }
        if hoursInt         > 0 { return hours }
        if minutesInt       > 0 { return minutes }
        if secondsInt       > 0 { return seconds }
        if millisecondsInt  > 0 { return milliseconds }
        return ""
    }
}

用途不同

// assume myTimeInterval = 96460.397    
myTimeInteval.stringFromInterval() // 1d 2h 47m 40s 397ms

斯威夫特5:

extension Int {

    func secondsToTime() -> String {

        let (h,m,s) = (self / 3600, (self % 3600) / 60, (self % 3600) % 60)

        let h_string = h < 10 ? "0\(h)" : "\(h)"
        let m_string =  m < 10 ? "0\(m)" : "\(m)"
        let s_string =  s < 10 ? "0\(s)" : "\(s)"

        return "\(h_string):\(m_string):\(s_string)"
    }
}

用法:

let seconds : Int = 119
print(seconds.secondsToTime()) // Result = "00:01:59"

以下是我在Swift 4+中使用的音乐播放器。我将秒Int转换为可读的字符串格式

extension Int {
    var toAudioString: String {
        let h = self / 3600
        let m = (self % 3600) / 60
        let s = (self % 3600) % 60
        return h > 0 ? String(format: "%1d:%02d:%02d", h, m, s) : String(format: "%1d:%02d", m, s)
    }
}

像这样使用:

print(7903.toAudioString)

输出:2:11:43