Lateinit variable not initialized error but got initialized (android)

I know that sounds weird.
So in my MainActivity am declaring an Array of the object SongInfo which looks like this:

class SongInfo {
    lateinit var title: String
    lateinit var contentId: String
    lateinit var filepath: String
}

This is how I am declaring the Array in my MainActivity:

lateinit var songInfo: Array<SongInfo?>

So, now when I press a button, the listener of this button executes this:

searchButton.setOnClickListener {
            val cursor = contentResolver.query(
                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                arrayOf(
                    "_id",
                    "_data",
                    MediaStore.Audio.Media.TITLE,
                    MediaStore.Audio.Media.ARTIST,
                    MediaStore.Audio.Media.DURATION
                ),
                "is_music == 1",
                null, null
            )

            songInfo = arrayOfNulls(cursor!!.count)

            for (index in songInfo.indices) {
                songInfo[index] = SongInfo()
                Log.d(tag, "searchButton: $index")
            }

            adapter = listMusicService.listMusic(cursor)
            adapter.notifyDataSetChanged()
        }

The ListMusicService class looks like this:

class ListMusicService(val context: Context, private var adapter: ArrayAdapter<Any>) {

    private val tag = "MusicShare/ListMusicService"

    fun listMusic(cursor: Cursor): ArrayAdapter<Any> {
        val activity = MainActivity()
        adapter.clear()

        val songInfo = arrayOfNulls<SongInfo>(cursor.count)

        var duration: Double

        var index = 0

        while (cursor.moveToNext()) {
            duration = ((cursor.getDouble(4) / 600).roundToInt() / 100).toDouble()

            adapter.add(cursor.getString(3) + ": " + cursor.getString(2) + " (" + duration + ")")

            val filepath = File(cursor.getString(1))

            Log.d(tag, "searchMusic: writing songInfo")

            songInfo[index] = SongInfo()

            songInfo[index]!!.title = filepath.name
            songInfo[index]!!.filepath = filepath.absolutePath
            activity.songInfo[index]!!.filepath = filepath.absolutePath
            songInfo[index]!!.contentId = cursor.getString(0)

            index++
        }

        return adapter
    }
}

Pressing the searchButton now causes a kotlin.UninitializedPropertyAccessException: lateinit property songInfo has not been initialized.
But I don't understand why because in the listener method of searchButton I'm initializing every object of the array. Does anybody know why this happens and maybe what goes wrong?

EDIT: Creating the ListMusicService:

val listMusicService = ListMusicService(this, adapter)

You are creating a new object of MainActivity

val activity = MainActivity()

which is just an empty object, instead you need to pass this as an instance of MainAcitiy to listMusic method and use it.

ListMusicService class already taking a context object so seems like you are passing the activity's instance (no code about it), use the existing adapter instance of MainAcitivty.

// somewhere in main activity 
val listMusicService = ListMusicService(this, adapter)

// inside searchButton.setOnClickListener
adapter = listMusicService.listMusic(cursor)
adapter.notifyDataSetChanged()

In ListMusicService

fun listMusic(cursor: Cursor): ArrayAdapter<Any> {
    adapter.clear()
    val songInfo = arrayOfNulls<SongInfo>(cursor.count)

    var duration: Double

    var index = 0

    while (cursor.moveToNext()) {
        duration = ((cursor.getDouble(4) / 600).roundToInt() / 100).toDouble()

        adapter.add(cursor.getString(3) + ": " + cursor.getString(2) + " (" + duration + ")")

        val filepath = File(cursor.getString(1))

        Log.d(tag, "searchMusic: writing songInfo")

        songInfo[index] = SongInfo()

        songInfo[index]!!.title = filepath.name
        songInfo[index]!!.filepath = filepath.absolutePath
        activity.songInfo[index]!!.filepath = filepath.absolutePath
        songInfo[index]!!.contentId = cursor.getString(0)

        index++
    }
    return adapter
}