Error while setting text on textView in kotlin-CodePudding

I am developing a music app, in player Activity when I try to assign a song title, album, and cover image in activity, it returns an error that late init var is not initialized, and when I remove that it works perfectly. Error is while I fetch info from a song using musicList[songPosition].artUri. Here is my player Activity.


import android.media.MediaPlayer
import android.os.Bundle
import android.widget.ImageButton
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import com.bumptech.glide.Glide
import com.bumptech.glide.request.RequestOptions
import com.google.android.material.imageview.ShapeableImageView

class musicInterface : AppCompatActivity() {

    lateinit var musicList: ArrayList<MusicClass>
    var songPosition: Int = 0
    var musicPlayer: MediaPlayer? = null

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

        val button: ImageButton = findViewById(R.id.backButton)
        button.setOnClickListener {
            onBackPressed()
        }

        setLayout()
        playSong()
    }

    private fun setLayout() {
        val image: ShapeableImageView = findViewById(R.id.interfaceCover)
        val title: TextView = findViewById(R.id.interfaceSongName)
        val album: TextView = findViewById(R.id.interfaceArtistName)

        Glide
            .with(this)
            .load(musicList[songPosition].artUri)
            .apply(RequestOptions.placeholderOf(R.drawable.image_as_cover).centerCrop())
            .into(image)

        title.text = musicList[songPosition].title
        album.text = musicList[songPosition].artist

    }

    private fun playSong() {
        songPosition = intent.getIntExtra("index", 0)
        when (intent.getStringExtra("class")) {
            "MusicAdapter" -> {
                musicList = ArrayList()
                musicList.addAll(MainActivity.songList)
                if (musicPlayer == null) musicPlayer = MediaPlayer()
                musicPlayer!!.reset()
                musicPlayer!!.setDataSource(musicList[songPosition].path)
                musicPlayer!!.prepare()
                musicPlayer!!.start()

            }
        }
    }
}

The error is given below.

    Process: com.example.music, PID: 25937
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.music/com.example.music.musicInterface}: kotlin.UninitializedPropertyAccessException: lateinit property musicList has not been initialized
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3420)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3559)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:96)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2092)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:264)
        at android.app.ActivityThread.main(ActivityThread.java:7593)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)
     Caused by: kotlin.UninitializedPropertyAccessException: lateinit property musicList has not been initialized
        at com.example.music.musicInterface.getMusicList(musicInterface.kt:14)
        at com.example.music.musicInterface.setLayout(musicInterface.kt:42)
        at com.example.music.musicInterface.onCreate(musicInterface.kt:27)
        at android.app.Activity.performCreate(Activity.java:7805)
        at android.app.Activity.performCreate(Activity.java:7794)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1306)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3390)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3559) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:140) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:96) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2092) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:264) 
        at android.app.ActivityThread.main(ActivityThread.java:7593) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)

Any suggestions.

CodePudding user response：

If you read the exception properly you can identify the issue. You're trying to load the image here inside setLayout() method, before you initialize the array.

.load(musicList[songPosition].artUri)

you're array initialization is written inside the next method call inside playSong()

 musicList = ArrayList()