Anroid : Kotlin : dismiss

Question

class MainActivity : AppCompatActivity() {

    lateinit var btn1 : Button
    lateinit var tv1 : TextView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        btn1 = findViewById<Button>(R.id.btn1)
        tv1 = findViewById<TextView>(R.id.tv1)

        // 1. dialog
        btn1.setOnClickListener {

            var dlg = AlertDialog.Builder(this@MainActivity)

            dlg.setTitle("title")
            dlg.setMessage("context here")
            dlg.setIcon(R.mipmap.ic_launcher)
            dlg.setPositiveButton("confirm", DialogInterface.OnClickListener{dialog, id ->

                })
                .create()

            dlg.show()
            
        }
        
    }
}

i want when click "comfirm"(positive-button) don't close dialog How do this?