Load more listener for RecyclerView

LoadMoreListener.kt

import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView

class LoadMoreListener(
    private val threshold: Int,
    private val listener: OnLoadMoreRequestedListener
) : RecyclerView.OnScrollListener() {

    companion object {
        fun attach(
            threshold: Int,
            recyclerView: RecyclerView,
            listener: OnLoadMoreRequestedListener
        ) {
            recyclerView.addOnScrollListener(LoadMoreListener(threshold, listener))
        }
    }

    override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
        val isScrollingToBottom = dy > 0

        if (isScrollingToBottom) {
            val layoutManager = recyclerView.layoutManager as? LinearLayoutManager ?: return

            val lastIndex = layoutManager.itemCount - 1
            val lastVisiblePosition = layoutManager.findLastVisibleItemPosition()
            val itemsToBottom = lastIndex - lastVisiblePosition

            val thresholdMet = itemsToBottom <= threshold

            if (thresholdMet) {
                listener.onLoadMoreRequested()
            }
        }
    }

    interface OnLoadMoreRequestedListener {
        fun onLoadMoreRequested()
    }
}