First off – I’m very new to app-coding, kotlin, xmls, etc. (Started teaching myself last week).
Having said that: I’m trying to write an activity in which an image is shown, and the user needs to press the corresponding button. (Specifically the image is of a g-clef note, and the buttons are just a list of note names, in Hebrew).
After pressing the button, I collect “correct or not” statistics, and show a “v” or “x” image so the user knows if they got it right, and then a new image is generated, until I’ve cycled through all images in the list of images to be learned.
The way I’ve got it set up, is that when a new image is generated, I redefine the button callbacks so that the correct button shows the “v” (and does a +1 to the correct answer stats, and moves on to the next image), and all the rest of the buttons show the “x” (and do a +1 to the incorrect stats, and don’t move on to the next image yet).

The problem I’m facing is that everything works except for showing the v/x image.
Stats are correctly collected, I checked. Adding a short “sleep” doesn’t help.
What am I doing wrong??

Here’s the code for what it’s worth. I’ve marked by comment the two lines that don’t do what I think they should, with the words “THIS IS NOT SHOWING”.

BTW, I’m sure there’re a ton of improvements to be made in this code, but as a beginner I’d appreciate focusing on the problem at hand and not on the plethora of general problems in my code, style, etc. 🙂

package com.example.test

import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.HorizontalScrollView
import android.widget.ImageView
import android.widget.LinearLayout
import android.widget.TextView
import androidx.activity.enableEdgeToEdge
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.ViewCompat
import androidx.core.view.WindowInsetsCompat

class GuessNotesGame : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()
        setContentView(R.layout.activity_guess_notes_game)
        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)

            val buttonschoicecontainer = findViewById<HorizontalScrollView>(R.id.scrollviewer)
            val linearbuttons = findViewById<LinearLayout>(R.id.linearbuttons)

            val correctim = findViewById<ImageView>(R.id.correctim)
            val wrongim = findViewById<ImageView>(R.id.wrongim)
            correctim.visibility = View.INVISIBLE
            wrongim.visibility = View.INVISIBLE

            buttonschoicecontainer.visibility = View.INVISIBLE;
            linearbuttons.visibility = View.VISIBLE;
            val listofnotes = listOf("c1", "d1", "e1", "f1", "g1", "a1", "b1", "c2")

            for (note in listofnotes) {
                val id: Int = resources.getIdentifier("choose" + note, "id", this.packageName)
                val btn_by_id = findViewById<Button>(id);
                btn_by_id.visibility = View.INVISIBLE;}

            val notesPlaceHolder = findViewById<ImageView>(R.id.notesplaceholder)

            val notesList = listOf(
                R.drawable.c1,
                R.drawable.d1,
                R.drawable.e1,
                R.drawable.f1,
                R.drawable.g1,
                R.drawable.a1,
                R.drawable.b1,
                R.drawable.c2)
            val notesNamesList = listOf("דו", "רה", "מי", "פה", "סול", "לה", "סי", "דו גבוה")

//            notesnameslist.shuffled()

            var numCorrect = 0
            var curIndex = 0
            var numIncorrect = 0

            fun runNextNote(ind: Int) {
                correctim.visibility = View.INVISIBLE
                wrongim.visibility = View.INVISIBLE

                val curCorrectNote = notesList[ind]
                val correctNoteName = notesNamesList[ind]
                notesPlaceHolder.setImageResource(curCorrectNote);
                buttonschoicecontainer.visibility = View.VISIBLE;
                linearbuttons.visibility = View.VISIBLE;

                for (note in listofnotes) {
                    val id: Int = resources.getIdentifier("choose" + note, "id", this.packageName)
                    val btn_by_id = findViewById<Button>(id);
                    btn_by_id.visibility = View.VISIBLE;
                    btn_by_id.setOnClickListener({
                        if (btn_by_id.text.toString() == correctNoteName) {
                            correctim.visibility = View.VISIBLE; // THIS IS NOT SHOWING
                            Thread.sleep(1_000)
                            curIndex = curIndex + 1
                            numCorrect = numCorrect + 1
                        }
                        else {
                            wrongim.visibility = View.VISIBLE; // THIS IS NOT SHOWING
                            Thread.sleep(1_000)
                            numIncorrect = numIncorrect + 1;
                        }
//                        Thread.sleep(2_000)
                        if (ind < notesNamesList.size - 1) {runNextNote(curIndex)}
                        else {
                            correctim.visibility = View.INVISIBLE
                            wrongim.visibility = View.INVISIBLE
                            val textViewResults = findViewById<TextView>(R.id.textViewResults);
                            textViewResults.visibility = View.VISIBLE;
                            notesPlaceHolder.setImageResource(R.drawable.gcleftreb)
                            textViewResults.text = "Correct: $numCorrect, Wrong: $numIncorrect";
                        }

            }
                );}



            }

            runNextNote(0)

            insets
        }
    }
}