Recycler view in Kotlin

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rec"/>
</LinearLayout>

MainActivity.kt

package com.example.recycle

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView

class MainActivity : AppCompatActivity() {
    var Course = arrayOf( "Android", "2", "PHP", "Android", "Java", "PHP", "Android", "Java", "PHP","Android","Java","PHP",
        "Android","Java","PHP","Android","Java","PHP","Android","Java","PHP","Android","Java","PHP","Android","Java","PHP",
        "Android","Java","PHP","Android","Java","PHP","Android","Java","PHP","Android","Java","PHP","Android","Java","PHP",
        "Android","Java","PHP" )
    var recyclerView: RecyclerView? = null
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        recyclerView = findViewById<View>(R.id.rec) as RecyclerView
        val layoutManager = LinearLayoutManager(this@MainActivity,LinearLayoutManager.VERTICAL,true)
        recyclerView!!.layoutManager = layoutManager

        val customAdapter = CustomAdapter(this@MainActivity, Course)
        recyclerView!!.adapter = customAdapter
    }
}

CustomAdapter.kt

package com.example.recycle

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.RecyclerView

class CustomAdapter(mainActivity: AppCompatActivity, course: Array<String>) :
    RecyclerView.Adapter<CustomAdapter.MyViewHolder>() {
    var Names: Array<String>
    var context: Context

    init {
        context = mainActivity
        Names = course
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val v =
            LayoutInflater.from(parent.context).inflate(R.layout.rowlayout, parent, false)
        return MyViewHolder(v)
    }

    override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
        holder.name.text = Names[holder.adapterPosition]
        holder.name.setOnClickListener {
            Toast.makeText(
                context,
                Names[holder.adapterPosition],
                Toast.LENGTH_SHORT
            ).show()
        }
    }

    override fun getItemCount(): Int {
        return Names.size
    }

    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var name // init the item view's
                : TextView

        init {
            // get the reference of item view's
            name = itemView.findViewById<View>(R.id.name) as TextView
        }
    }
}

rowlayout.xml

<?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="wrap_content"
    android:orientation="vertical"
    android:background="#fff">
    <!--
    items for a single row of RecyclerView
    -->
    <TextView
        android:id="@+id/name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:textColor="#FF5722"
        android:textSize="20sp" />
</LinearLayout>