How to sort arraylist of ZonedDateTime in Kotlin?

Question

I am trying to create a messaging app in Android and I need to sort the messages according to their timestamps, which I created from a ZonedDateTime object. I was going to parse the timestamp strings with the formatter I used to re-create a ZonedDateTime object, but I need to be able to sort the arraylist of ZonedDateTime objects in chronological order. How can I do this?

Possibly related: [Java - Result when compare two ZonedDateTime is not as expected](https://stackoverflow.com/questions/49686272/java-result-when-compare-two-zoneddatetime-is-not-as-expected) — Ole V.V., Aug 15 '20 at 11:05

score 0 · Accepted Answer · answered Aug 13 '20 at 22:01

sorted() is the way to sort items in a list.

sort() will sort a mutable list or array.

In the Kotlin documentation, there are allusions to sorting by a natural order which only means that the class needs to implement the Comparable interface. ZonedDateTime implements ChronoZonedDateTime which implements Comparable so these methods should work.

How to sort arraylist of ZonedDateTime in Kotlin?

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