best way to destroy an gameobject in unity

Question

MissingReferenceException: The object of type 'GameObject' 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. grid.objGridSize () (at Assets/scripts/grid.cs:119) grid.hit (System.String hitObjString) (at Assets/scripts/grid.cs:109) grid.Update () (at Assets/scripts/grid.cs:80)

I'm getting this error and strange results after finding a gameobject, storing it in a new GameObject variable and then destroying it:

void Update () {
    if(Input.GetButtonDown("Fire1")){ // detect left mouse click

        ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        Debug.Log("clicked");

        if(Physics.Raycast(ray, out hitObj)){
            if(hitObj.collider != null){

                // send a message to the object that got hit
                hit(hitObj.collider.gameObject.name);
            }
        }
    }
}
public void hit(String hitObjString){

    Debug.Log("I got hit: "+name);

    GameObject hitTile = GameObject.Find(hitObjString);

    if( hitTile.tag == "tile"){

        Destroy(hitTile);
    }
}

Answer 1

Passing through the gameObject name to a method, then using GameObject.Find to find it again by its name, is bad practice, and inefficient.

GameObject.Find is an expensive operation.

Rather do something like this...

    void Update () {
    if(Input.GetButtonDown("Fire1")){ // detect left mouse click

        ray = Camera.main.ScreenPointToRay(Input.mousePosition);

        Debug.Log("clicked");

        if(Physics.Raycast(ray, out hitObj)){
            if(hitObj.collider != null){
                hit(hitObj);
            }
        }
    }
}
public void hit(GameObject hitObj){

    Debug.Log("I got hit: "+ hitObj.name);

    if( hitObj.tag == "tile"){

        Destroy(hitObj);
    }
}