im new in kotlin , reset button doesnt work when i change app into dark mode but when i start count and click on it again it work

 private lateinit var countertxt: TextView
    private lateinit var buttonclick: Button
    private lateinit var resetbutton: Button
    private var num = 0
    private lateinit var mediaPlayer: MediaPlayer


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        countertxt = findViewById(R.id.countertxt)
        buttonclick = findViewById(R.id.buttonclick)
        resetbutton = findViewById(R.id.resetbtn)


        buttonclick.setOnClickListener {
            num++

            countertxt.text = num.toString()


            val mediaPlayer = MediaPlayer.create(this, R.raw.sound)
            mediaPlayer.start()

            mediaPlayer.setOnCompletionListener {
                buttonclick.isEnabled = true
                mediaPlayer.release()


            }
            resetbutton.setOnClickListener {

                num = 0
                countertxt.text = num.toString()

                val mediaPlayer = MediaPlayer.create(this, R.raw.sound)
                mediaPlayer.start()

                mediaPlayer.setOnCompletionListener {
                    buttonclick.isEnabled = true
                    mediaPlayer.release()
                }

            }
        }
    }
    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)

        val countertxt :Int = num

        outState.putInt("SavedInt",num)
    }

    override fun onRestoreInstanceState(savedInstanceState: Bundle) {
        super.onRestoreInstanceState(savedInstanceState)

        val userInt = savedInstanceState.getInt("SavedInt",0)
        num = userInt
        countertxt.text = num.toString()
    }
}

i want to know what is the code that make reset button reset to 0 correctly i think the problem in my code can anyone help me please?

You are creating and adding your reset button’s click listener inside the other button’s click listener, so the reset button won’t do anything until the other button has been clicked at least once since the last time the screen (activity or fragment) reloaded.

You need to move a closing brace } from after your reset button’s click listener to before before the resetbutton.setOnClickListener { line.

buttonclick.setOnClickListener {
    num++

    countertxt.text = num.toString()
    val mediaPlayer = MediaPlayer.create(this, R.raw.sound)
    mediaPlayer.start()

    mediaPlayer.setOnCompletionListener {
        buttonclick.isEnabled = true
        mediaPlayer.release()
    }
}
resetbutton.setOnClickListener {

    num = 0
    countertxt.text = num.toString()

    val mediaPlayer = MediaPlayer.create(this, R.raw.sound)
    mediaPlayer.start()

    mediaPlayer.setOnCompletionListener {
        buttonclick.isEnabled = true
        mediaPlayer.release()
    }
}

You are creating the button click listener inside a button click listener. You need to move the } bracket before reset button and after doing this change it will work fine.

I see you've already fixed this problem, but another thing is, you are creating:

val countertxt :Int = num

in onSaveInstanceState overriding function and then not using it, remove it or use it.