ListView에서 ListViewAdapter를 만들었는데 이렇게 뜹니다

import android.view.View
import android.view.ViewGroup
import android.widget.BaseAdapter

class ListViewAdapter(val List : MutableList<String>) : BaseAdapter() {
    override fun getCount(): Int {
        return List.size

    }

    override fun getItem(p0: Int): Any {
        return List[position]
    }

    override fun getItemId(p0: Int): Long {
        return position.toLong()
    }

    override fun getView(p0: Int, p1: View?, p2: ViewGroup?): View {

        var convertView = convertView

        if (convertView == null) {

        }
    }