An iteration of a ViewPager2 adapter that displays data in a grid

grid_pager_page_layout2.xml

<?xml version="1.0" encoding="utf-8"?>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/grid_pager_view"
    android:horizontalSpacing="4dp"
    android:verticalSpacing="4dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

GridPageHolder2.kt

import android.view.View
import android.widget.GridView
import androidx.recyclerview.widget.RecyclerView
import xyz.binary.foxlauncher.R

class GridPageHolder2(itemView: View) : RecyclerView.ViewHolder(itemView) {

    val gridView: GridView = itemView.findViewById(R.id.grid_pager_view)

}

GridPagerAdapter2.kt

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ArrayAdapter
import android.widget.GridView
import androidx.recyclerview.widget.RecyclerView
import xyz.binary.foxlauncher.R
import java.util.*
import kotlin.collections.ArrayList
import kotlin.math.ceil

abstract class GridPagerAdapter2<T>(
    val context: Context,
    val columns: Int,
    val rows: Int
) : RecyclerView.Adapter<GridPageHolder>() {

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): GridPageHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.grid_pager_page_layout2, parent, false)
        return GridPageHolder(view).apply {
            gridView.numColumns = columns
        }
    }

    override fun getItemCount(): Int {
        val itemsPerPage = columns * rows
        var pages = round((getSize() / itemsPerPage).toDouble()).toInt()
        val availableSlots = pages * itemsPerPage
        if (getSize() - availableSlots > 0) {
            pages += 1
        }
        return pages
    }

    override fun onBindViewHolder(holder: GridPageHolder, position: Int) {
        val grid = holder.gridView
        val maxItems = columns * rows
        val offset = maxItems * position
        val items = ArrayList<T>()
        for (i in 0 until maxItems) {
            try {
                items.add(getItem(i + offset))
            } catch (e: IndexOutOfBoundsException) {
                break
            }
        }
        grid.adapter = GridAdapter(context, items)
    }

    abstract fun getViewItem(item: T, convertView: View?, parent: ViewGroup): View

    abstract fun getItem(position: Int): T

    abstract fun getSize(): Int

    inner class GridAdapter<R>(
        context: Context,
        val items: List<R>,
    ) : ArrayAdapter<R>(context, 0, items) {

        constructor(context: Context) : this(context, Collections.emptyList())

        @Suppress("UNCHECKED_CAST")
        override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
            val item: R = this.items[position]
            val view = this@GridPagerAdapter.getViewItem(item as T, convertView, parent)
            // TODO Listeners
            return view
        }

    }

}