GridView(kotlin)

package com.nekotype.ips.thechoice
 
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter
import android.widget.ImageView
import kotlinx.android.synthetic.main.grid_item.view.*
 
// ①抽象クラスの実装追加
class GridAdapter(val context: Context, val layoutid:Int, val iconlist:MutableList<Int>):BaseAdapter()
{
    override fun getView(p0: Int, p1: View?, p2: ViewGroup): View? {
 
        // ③実装追加
        val (viewHolder, view)=when(p1){
            null->{
                // grid_item -> view -> holder
                // grid_itemをインフレーとしてviewを作成
                val view= LayoutInflater.from(p2?.context).inflate(R.layout.grid_item,p2,false) as View
                // ViewHolderを生成
                val holder=ViewHolder()
                // ViewHolderとgrid_itemを関連づける
                holder.imageView=view.image_view
                view.tag=holder
                holder to view
            }
            else->{
                p1.tag as ViewHolder to p1
            }
        }
 
        // holderに値を設定する
        val objectItem = iconlist[p0]
        if (objectItem != null) {
            viewHolder.imageView?.setImageResource(R.drawable.man)
        }
 
 
        return view
 
    }
 
    override fun getItem(p0: Int): Any {null
        return 0
    }
 
    override fun getItemId(p0: Int): Long {
        return 0
    }
 
    override fun getCount(): Int {
        return iconlist.size
    }
}
 
// ②getViewで使うViewholderクラス追加。RecycleViewなら不要？
internal class ViewHolder {
    var imageView: ImageView? = null
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:background="#afc"
    android:orientation="vertical"
    android:gravity="center"
    android:padding="3dp" >
 
    <ImageView
        android:id="@+id/image_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
 
</LinearLayout>