Imageview in Kotlin

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/android" />
    <Button
        android:id="@+id/btnChangeImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Change Image" />

</LinearLayout>

MainActivity.kt

package com.androidian.imageview

import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {
    var button: Button? = null
    var image: ImageView? = null
    public override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        addListenerOnButton()
    }

    fun addListenerOnButton() {
        image = findViewById(R.id.imageView1)
        button = findViewById<View>(R.id.btnChangeImage) as Button
        button!!.setOnClickListener { image!!.setImageResource(R.drawable.ic_launcher_background) }
    }
}