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android – Using a kotlin library in java code

Posted by: admin June 15, 2020 Leave a comment


I have a kotlin library FlowLayout lib as aar,

and want to use it in my java code (android) but can not to resolve kotlin.Pair.

FlowLayoutManager layoutManager=new FlowLayoutManager(3, RecyclerView.HORIZONTAL, new FlowLayoutManager.Interface() {
     public kotlin.Pair<Integer, Integer> getProportionalSizeForChild(int i) {
         return null;

I have tried android.support.v4.util.Pair but is not compatible. How can I use a kotlin lib in java code with their object dependencies?

How to&Answers:

Class kotlin.Pair belongs to the standard library org.jetbrains.kotlin:kotlin-stdlib:1.0.0, so you must have this library as a dependancy.

It is NOT recommended to use Pair in public APIs. Rather than that, create your own data class with 2 properties and give them a clearer naming than first and second.

The purpose of Pair is to server as a temporary data carrier in any intermediate operation. If you use it in your API, you lose in clarity.