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Question by anthogd · Jun 17, 2020 at 09:55 AM · nullreferenceexceptionlistschildren

List becomes null in Parent when filled in child script,List becomes null within own class after being filled in other class

Dear all,

I am trying to fill a list of Gameobjects that I spawn every X seconds. T$$anonymous$$s list is instantiated in one class (PickUpWeapons) as such:

 public List<GameObject> weaponsToPickUp = new List<GameObject>();     //list of weapons spawned over the course of the game

And in my class where I spawn weapons (SpawnObjects), I fill t$$anonymous$$s list as such: PickUpWeapons pickUp; //reference to pickUpWeapons class

     //instanciate
     private void Start() {
         //generate instance of the pool
         objectPooler = ObjectPooler.Instance;
 
         pickUp = gameObject.AddComponent<PickUpWeapons>();  //instanciate the class
         //pickUp.weaponsToPickUp = new List <GameObject>();
     }
 
     private void FixedUpdate() {
         //only spawn objects if it is time
         if (Time.time > nextSpawnTime) {
             //update next spawn time
             nextSpawnTime = Time.time + spawnRateWeapons;
             //where we spawn the weapons
             float randomXPos = Random.Range(- xMax, xMax);
             whereToSpawn = new Vector2(randomXPos, transform.position.y);
             //generate object
             GameObject bullet = ObjectPooler.Instance.SpawnFromPool("Bullet", whereToSpawn, Quaternion.identity);
             //freeze its position on X only
             bullet.GetComponent<Rigidbody2D>().constraints = RigidbodyConstraints2D.FreezePositionX;
 
             //add weapon generated as a potentially picked up weapon
             pickUp.weaponsToPickUp.Add(bullet);
             Debug.Log(pickUp.weaponsToPickUp.Count);
         }
     }
 }

In t$$anonymous$$s class (SpawnObjects) pickUp.weaponsToPickUp is not empty and the Log does indicate an increase in size of weaponsToPickUp. However, back in PickUpWeapons class, t$$anonymous$$s list is now empty.

Does anyone know what I could do to solve t$$anonymous$$s please?

Best Regards, Anthony Guillard

,Dear all, I have the two following classes, one that creates items and the other that enables the user to pick them up.

In my class PickUpWeapons, I create a list of GameObjects

     public List<GameObject> weaponsToPickUp = new List<GameObject>();     //list of weapons spawned over the course of the game


W$$anonymous$$ch is filled in the class SpawnObjects

     PickUpWeapons pickUp;     //reference to pickUpWeapons class
 
     //instanciate
     private void Start() {
         //generate instance of the pool
         objectPooler = ObjectPooler.Instance;
 
         pickUp = gameObject.AddComponent<PickUpWeapons>();  //instanciate the class
         pickUp.weaponsToPickUp = new List <GameObject>();
     }
 
 
  private void FixedUpdate() {
         //only spawn objects if it is time
         if (Time.time > nextSpawnTime) {
             //update next spawn time
             nextSpawnTime = Time.time + spawnRateWeapons;
             //where we spawn the weapons
             float randomXPos = Random.Range(- xMax, xMax);
             whereToSpawn = new Vector2(randomXPos, transform.position.y);
             //generate object
             GameObject bullet = ObjectPooler.Instance.SpawnFromPool("Bullet", whereToSpawn, Quaternion.identity);
             //freeze its position on X only
             bullet.GetComponent<Rigidbody2D>().constraints = RigidbodyConstraints2D.FreezePositionX;
 
             //add weapon generated as a potentially picked up weapon
             pickUp.weaponsToPickUp.Add(bullet);
 }
 }
 
 }


But when I access again the list weaponsToPickUp in PickUpWeapons (its class), the list is null/empty and does not contain the bullets spawned anymore w$$anonymous$$ch is problematic as I cannot detect the collisions afterwards.

Does anyone know how to solve t$$anonymous$$s please?

Best Regards, Anthony Guillard

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