Audio doesn't play when instantiate new object

Question

I'm facing audio problems in my project. There are three paddle game objects and one cube. Cube has Rigidbody2d or BoxCollider2d. And there is also a button script attach to cube which has button function when we click on button cube Kinematic becomes false and drop on the paddle. When it's collide with any paddle cube destroy and instantiate again with new prefab. When Cube is falling sound is play and cube is destroy. New cube is instantiate when again click on button then error came.

MissingReferenceException: The object of type AudioSource has been destroyed but you are still trying to access it. Your script should either check if it is null or you should not destroy the object.

Scripts on all paddles:

public class Paddle : MonoBehaviour
{
    [SerializeField]
    private AudioSource source;
    [SerializeField]
    private AudioClip hit;
    [SerializeField]
    private BoxCollider2D collide;
    [SerializeField]
    private GameObject Clone;

    void Awake()
    {
        collide.isTrigger = true;
    }

    void OnTriggerEnter2D(Collider2D target)
    {
        source.PlayOneShot(hit);
        Destroy(target.gameObject);
        Instantiate(Clone, new Vector3(0f, 4.51f, 0f), Quaternion.identity);
    }
}

Cube Script:

public class Cube : MonoBehaviour 
{
    [SerializeField]
    private AudioSource source;
    [SerializeField]
    private Rigidbody2D body;
    [SerializeField]
    private AudioClip play;
    private Button bt;
    private float pos;
    public bool check;

    void Start()
    {
        bt = GameObject.FindGameObjectWithTag("Button").GetComponent<Button>();
        bt.onClick.AddListener(Fire);
        body.isKinematic = true;
    }

    void Update()
    {
        if (check)
        {
            return;
        }

        Vector3 temp = transform.position;
        pos = Camera.main.ScreenToWorldPoint(Input.mousePosition).x;
        temp.x = Mathf.Clamp(pos, -6.25f, 6.25f);
        body.position = temp;
    }

    public void Fire()
    {
        GameObject.FindGameObjectWithTag("Player").GetComponent<Cube>().check = true;
        GameObject.FindGameObjectWithTag("Player").GetComponent<Rigidbody2D>().isKinematic = false;
        source.PlayOneShot(play);
    }
}

Cube image:

Paddles image:

New Export package: https://drive.google.com/file/d/0B1H5fdK2PJAnSXVPdmE5Z3J1SUU

Problem in Video: https://drive.google.com/file/d/0B1H5fdK2PJAnYzRfVnlQT1FyTlE

You should show the methods that the button calls, the one creating the new cube. I guess it is calling on the cube and is linked to the old AudioSource that is destroyed with the first cube. You would have to update the reference with the new AudioSource attached on the new Cube. — Everts
@fafase on Cube Script public void Fire() method call on button click and in paddle image i show a clone prefab which add in paddle inspector — Ven Nilson

Everts Everts · Accepted Answer · 2015-12-20T14:19:35

Your linked package works fine, it does play the sound every time I launch and destroy a cube.

Nonetheless, you should remove the method on destroy. Unity does not throw any error nor warning when a non-persistent listener is null, kinda weird but this is how it is. You should remove it manually:

void OnDestroy(){
    bt.onClick.RemoveListener (Fire);
}

But your package does not throw any error when I run it.

Though, I would rethink your approach, instead of the cube assigning its Fire method to the Button event, I would have a script on the button containing the Fire method as well as the AudoiSource and clip. Then on Start, the Cube would pass itself so that the button could access its Cube and Rigidbody2D component.

Best would be to pass a class that contains those are members:

public class CubeArgument{
    public readonly Rigidbody2D rg = null;
    public readonly Cube cube = null;  
    public CubeArgument(Rigidbody2D rg, Cube cube){
        this.rg = rg;
        this.cube = cube;
    }
}

then here goes your Cube start method:

void Start () {
    bt = GameObject.FindGameObjectWithTag ("Button");
    bt.GetComponent<ButtonController> ().Init(new CubeArgument(body, this));
    body.isKinematic = true;
}

The ButtonController reference could even be made static since there is only one for the whole level.

and then on the button you have a ButtonController:

public class ButtonController : MonoBehaviour{

     Cube currentCube = null;
     Rigodbody2D currentRig = null;
     public void Init(CubeArgument ca){
         currentRig = ca.rg;
         currentCube = ca.cube;
     }
     public void Fire(){
         if(currentCube != null){ currentCube.check = true; }
         if(currentRig != null) { currentRig.isKinematic = false; }
     }
}

Fire is passed as listener to the Button onClick and this is it.

Audio doesn't play when instantiate new object

3 Answers