[lb8] LeftFragment.kt

package com.example.lb8

import android.content.Context
import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ArrayAdapter
import android.widget.ListView
import androidx.fragment.app.Fragment

class LeftFragment() : Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?): View? {
        val view = inflater.inflate(R.layout.fragment_left, container, false)

        val listOptions = view.findViewById<ListView>(R.id.list_fruits)
        listOptions.adapter = ArrayAdapter<String>(context!!,
            R.layout.my_list_item,
            arrayOf("+", "-", "*"))
        listOptions.setOnItemClickListener { parent, view, position, id ->
            (mainContext as OnDataListener).onData(position)
        }

        return view
    }

    override fun onAttach(context: Context) {
        super.onAttach(context)
        mainContext = context
    }
    private lateinit var mainContext: Context


}