List resets on enter playmode

Unity Editor Workflows
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1

Hi. So my problem is that when I go into playmode, my serialization made in inspector for some reason resets and i get null exception and so my code don’t work.

Some of my code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class TrackList : MonoBehaviour
{
    [SerializeField] private List<Track> trackObjects;
    [SerializeField] private List<AudioClip> audioTracks;
    public AudioClip CurrentTrack { get; private set; }
    public static bool TrackChanged { get; set; }

    private void Awake()
    {
        if (trackObjects == null)
        {
            trackObjects = new List<Track>();
        }
    }

    public void PrepareTracklistButtons(Game game, Clicker clicker)
    {
        for (int i = 0; i <= trackObjects.Count - 1 ; i++)   //just i < ...Count, try it
        {
            GameObject trackObject = trackObjects[i].gameObject;
            Button button = trackObject.GetComponentInChildren<Button>();

            button.onClick.AddListener(game.SwitchCanvas);
            button.onClick.AddListener(() => ChangeData(clicker, trackObject)); //change elements in playmode
        }
    }

Here i get an exception in line

GameObject trackObject = trackObjects[i].gameObject;

Cause trackObjects elements are becoming null for some reason

This is TrackList object before I enter playmode:

image
image443×715 22.6 KB

as you can see trackObjects are serialized, but after I enter playmode it gets reset to null
Track script is attached to Track object, of course

I also don’t have any code reseting it somewhere in start or awake methods

This is my track class:

using UnityEngine;

public class Track : MonoBehaviour
{
    private void Start()
    {
        
    }

    private void Update()
    {
        
    }
    //private bool completed;
    //private AudioClip clip;
}

Its empty, could this be a reason? I tried to make fields public, still no use

What I am trying to do is to get reference from GO to which track is attached to, I used to have list of GameObjects and it worked fine, I can get back to this implementation of course, but I wish to know, why current implementation doesnt work,
Thanks in advance.

2

Of course, the code here makes a new list …

3

it was added later, if i remove this code, It doesnt change anything
plus it creates a new list ONLY if it is null :slight_smile:

4

Are these referenced components on objects in the same scene, and the objects and the components are not being destroyed when entering the scene?

5

I also don’t see any reason why this shouldn’t work, it’s a common pattern. CodeSmile is on a good track: are these just regular GOs in the same scene, or is there some sort of trickery?
More info on the setup always helps.

6

Which btw is unnecessary, you can simply new() the field so it’ll never be null:

[SerializeField] private List<Track> trackObjects = new();

Won’t change any existing scripts on objects since they may already have the field serialized as null. But it’s good habit to get into to initialize fields with a default value.

7

that’s right, everything’s on the same scene, I need here 2 'scenes’which I implemented with 2 canvases, i just switch them in hierarchy when needed

I dunno, guys, it’s definitely some bug, I made some experimenting around:
firstly I tried to create a new list a do the same thing with it, it never reseted, then
I thought maybe the problem is with name of class or variable name , replaced it and it broke in new class, then went back to old class and… uuhhmm so what I’m trying to say is that I have now all the same code with the same hierarchy and everything works fine for some reason, I dont know wtf was that xD
Thanks anyway for your replies