How to set button click event with kotlin 4

MainActivity.kt

class MainActivity : AppCompatActivity(), View.OnClickListener {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        findViewById<Button>(R.id.btn1).setOnClickListener(this)
    }

    override fun onClick(v: View) {
        Snackbar.make(v, "ボタン１が押されました", Snackbar.LENGTH_SHORT).show()
    }
}