什么是 java.time.Duration 的 Android 等价物？

Question

I need to use something like the class java.time.Duration to express time intervals from sub-microsecond to seconds. But Android Studio doesn't offer me this option.

I suppose I could use a float and express everything as seconds, but this seems less intuitive and meaningful.

These intervals aren't associated with any real-world timeline, they're just, well, intervals.

Answer 1

Back-port

See the back-port of much of java.time to Java 6 & 7, and its adaptation for Android . See details below.

The back-port includes the org.threeten.bp.Duration class.

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About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date , Calendar , & SimpleDateFormat .

The Joda-Time project, now in maintenance mode , advises migration to the java.time classes.

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations. Specification is JSR 310 .

Where to obtain the java.time classes?

• Java SE 8 and SE 9 and later
  • Built-in.
  • Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and SE 7
  • Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport .
• Android
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP… .

Answer 2

You may find that importing the JodaTime library and use the duration class from that could be helpful since you do not have access to the java.time library. From what I can gather the Interval and ReadableDuration classes may be useful, but neither explicitly provide a getSeconds() method.

If you can use the above classes to store your time duration you could possibly create a static class to convert milliseconds into a seconds in a more intuitive way.

float durationInSeconds MyTime.milliToSeconds(myDuration.getMillis())

Answer 3

As is noted at ThreeTenABP you should use desugaring if your gradle plugin is v4.0

Here you can find how to turn on desugaring: android library desugaring

It's pretty simple.