DateComponentsFormatter可以格式化小数秒吗？

Question

我想打印,例如,值1.5为"1.5秒",就像Safari的时间轴一样,我正在尝试使用DateComponentsFormatter.

不幸的是,它.allowedUnits只能归结为.second(即使枚举有.nanosecond).我尝试过设置.allowsFractionalUnits = true,但我仍然得到"0秒".

有没有办法从DateComponentsFormatter中获得小数秒？

Answer 1

对于位置单位样式，DateComponentsFormatter可以与 一起使用NumberFormatter来获取区域设置感知字符串。

func format(_ seconds: TimeInterval) -> String {
  let components = DateComponentsFormatter()
  components.allowedUnits = [.minute, .second]
  components.allowsFractionalUnits = true // does not work as expected
  components.unitsStyle = .positional
  components.zeroFormattingBehavior = .pad

  let fraction = NumberFormatter()
  fraction.maximumIntegerDigits = 0
  fraction.minimumFractionDigits = 0
  fraction.maximumFractionDigits = 3
  fraction.alwaysShowsDecimalSeparator = false

  let fractionalPart = NSNumber(value: seconds.truncatingRemainder(dividingBy: 1))

  return components.string(from: seconds)! + fraction.string(from: fractionalPart)!
}

print(Locale.current) // ru_RU (current)
print(format(600.5))  // 10:00,5 <- note locale specific decimal separator

不幸的是，将此方法用于其他日期样式更加困难。