im trying to make a card game. There is something I can't understand:
I have a class named HandManagement that has a list of GameObject and a method AddToHand that add to a list (the hand) a gameobject passed through variable (bringing in hand)
I have a Tile GameObject on the screen with a script that, when collides with mousedown:
the variable hand of HandManagement type is called with method AddToHand to add that gameobject to hand (AddToHand(this.gameobject)
When I try unity tells me that the object doesnt exist..
Why?
Thank you
Tile Class:
{
m_ObjectCollider.isTrigger = true;
tileInHand.PickTile (tileName);
HandManagement Class:
public GameObject tile;
public List<GameObject> hand = new List<GameObject>();
public void PickTile(string pickedTile)
{
Debug.Log ("picked");
tile = Instantiate (tile);
tile.transform.SetParent (transform, false); //i put it in a grid of hand card
hand.Add (tile); //I add it to the list of card in hand
}}
first of all, change the string to a GameObject, then Instantiate it
public void PickTile(GameObject pickedTile)//change it from string to gameobject
{
Debug.Log ("picked");
tile = Instantiate (pickedTile);//instantiate the picked tile.
tile.transform.SetParent (transform, false);
hand.Add (tile);
}}
now tile holds the GameObject "pickedTile" so it will be added to the grid and to the hand.
Next, you need to change the referenced object from a string to a GameObject
tileInHand.PickTile(tileGameObject);
The Instantiate function copies the object tile into tile, this is empty to begin with. Try instantiating a prefab gameobject into the tile, or make sure gameobject tile is never empty (eg. by setting it in the Start()).
https://docs.unity3d.com/ScriptReference/Object.Instantiate.html
Related
I'm making a solitaire game and I strugle with one functionality.
In time of player is clicking on deck cards appears in discard pile. They are created in factory :
[SerializeField]private GameObject prefab;
public void Create(Transform parent, float zOffset, float yOffset, CardModel model, bool isCovered, bool isLast, string pileName, GameObject curretPile, ActionsManager manager)
{
GameObject instance = Instantiate(prefab, new Vector3(parent.position.x, parent.position.y - yOffset, parent.position.z - zOffset), Quaternion.identity, parent);
this.model = model;
this.view = instance.GetComponent<CardView>();
this.controller = GetComponent<CardController>();
instance.GetComponent<CardController>().SetModel(this.model);
instance.GetComponent<CardController>().SetView(view);
string spriteName = (instance.GetComponent<CardController>().ReturnValue()).ToString() + instance.GetComponent<CardController>().ReturnSuit();
Sprite faceingSprite = uncoverSprite.Find(item => item.name == spriteName);
instance.GetComponent<CardController>().SetUncoveredSprite(faceingSprite);
instance.GetComponent<CardController>().SetPileName(pileName);
instance.GetComponent<CardController>().SetIsCoveredBool(isCovered);
instance.GetComponent<CardController>().SetIsLastInPile(isLast);
instance.GetComponent<CardController>().SetActionsManager(manager);
instance.GetComponent<CardController>().SetCurrentPile(curretPile);
When all cards are created to discard pile and player click again on deck it sends action with demand of the list of card from discard pile, they are returning to deck and they are destroy in discard pile.
public void OnCardDemand()
{
List<CardModel> list = ReturnList();
RemoveAllElementsFromList();
if(OnDeckSend != null)
{
OnDeckSend(list);
}
CardController[] cards = gameObject.GetComponentsInChildren<CardController>();
foreach(CardController card in cards)
{
Destroy(card.gameObject);
}
}
Cards should be instatiated again after clicking on deck pile but there is an error :
MissingReferenceException: The object of type 'SpriteRenderer' has been destroyed but you are still trying to access it.
How can I destroy cards without any error?
It's a deck of cards - I wouldn't try to continuously create and destroy them, just assign new transform parents and set local positions to zero if you want to move them. I'd also recommend using SetActive(false) instead of destroying, then you can use SetActive(true) to "create" them back - this is along the lines of an object pool.
Ultimately the problem is that you've cached a reference to a Component on the GameObject that you're deleting, Wherever you're using the SpriteRenderer you need a null check, or else you need a more sophisticated way to unsubscribe that reference in OnDestroy for the GameObject your destroying.
I have an idea that there must be a way to attach a class to a prefab - basically to add my own methods to the code. Then, when I instantiate my prefab in runtime I want it to be an instance of this class.
Now, I can attach a script to a prefab and it's Start and Update works, but my idea is something like this:
public class PowerupWidget : MonoBehaviour {
void Start() {
Debug.Log("PowerupWidget created!!!");
}
void SetTitle(string title) {
// ... set the prefab's title widget text ...
}
}
When I instantiate my prefab, the Start method is called. But the instance is of course the GameObject type.
// in my scene script:
// prefab is my PowerupWidget
GameObject p = Instantiate(prefab, transform.position, Quaternion.identity, this.transform);
// here p is GameObject of course
Is there a way how to get to the instance of the PowerupWidget class, or am I completely wrong in my assuptions?
Structure in unity :
Things are divided into entities and component, when entities are gameobject and components are classes(Script) that are attached to this gameobject.
You just need to do this
PowerupWidget yourWidget = p.GetComponent<PowerupWidget>();
I'm currently experiencing a coder's block right now as I'm trying to instantiate text on a game object, specifically a Zombie prefab. I've gotten down the enemy's position for the text to be spawned but can't seem to make it follow the zombie's movement as it walks towards the player.
This is my 'Word Spawner' script.
public GameObject wordpb; // my word prefab
public Transform canvas; // connected to a canvas ui that has world camera set
public EnemyOne enemy;
public DisplayWord Spawn()
{
Vector2 targetPos = new Vector2(enemy.transform.position.x, enemy.transform.position.y);
GameObject wordobj = Instantiate(wordpb, targetPos, Quaternion.identity, canvas);
DisplayWord displayWord = wordobj.GetComponent<DisplayWord>();
return displayWord;
}
and this is where the DisplayWord class is derived from.
public Text text;
public void SetWord(string word)
{
text.text = word;
}
public void ThrowLetter()
{
text.text = text.text.Remove(0, 1);
text.color = Color.red;
}
public void ThrowWord()
{
Destroy(gameObject);
}
My best guess is that I should be implementing a void Update method in which I use transform.Translate? Or should I put a placeholder that acts as a child class to my Zombie prefab and attach the DisplayWord script there? Please help a poor soul out.
How does the text relate to the Zombie game object? Knowing what the text is for in relation to the zombie might inform the best way to make it follow the game object.
If the text is something like a worldspace nametag, instead of translating in Update you could make the text a child of the game object it needs to follow. It might not be the most elegant solution but if you give each text its own worldspace canvas you could assign the text as a child of the zombie, or, if you know you'll always have text following a zombie, you could just add a worldspace canvas and text to the zombie prefab...
To instantiate as a child you'd need to rework your word prefab to be its own worldspace canvas with your text as its child.
You can assign a parent when you instantiate:
wordobj = Instantiate(wordpb, enemy);
Or set the parent after instantiation:
wordobj.transform.SetParent(enemy.gameObject.transform, true);
The second parameter in SetParent is 'worldPositionStays', and controls whether the child object keeps its world position (true) or whether it's transform is evaluated relative to its new parent's transform. You could make it work either way: if you leave it 'true' you don't need to change the rest of your code, but I think if you make it false you don't need to get the enemy GameObject's position... The same is true for Instantiate when a parent is assigned but no transform position/rotation. So I think you could skip the step of finding the enemy's position and rewrite your Spawn code to:
public GameObject wordpb; // my word prefab
public EnemyOne enemy;
public DisplayWord Spawn()
{
GameObject wordobj = Instantiate(wordpb, enemy, false);
DisplayWord displayWord = wordobj.GetComponent<DisplayWord>();
return displayWord;
}
You'd need to assign the newly instantiated canvas's worldspace camera to make this work...
I have set up a random spawner that creates new game objects but they are being created outside of my canvas and therefore can't be seen when play the game. Is there any way to fix this? The objects 'neg thoughts' are UI Buttons and are being created outside of the canvas even though I need them to appear on screen so they can be used.
I did see a similar question but the suggestions didn't work for my problem.
this is very frustrating for me and any help would be awesome!
You can simply pass the parent into Instantiate
parent Parent that will be assigned to the new object
var newObj = Instantiate(prefab, parentTransform);
or with additional transforms
var newObj = Instantiate (prefab, position, rotation, parentTransform);
Or as others already said you can still do it afterwards at any time either by simply assigning a new transform.parent
newObj.transform.parent = parentTransform;
or using transform.SetParent
newObj.transform.SetParent(parentTransform, worldPositionStays);
The advantage of the later is that you have an optional parameter worldPositionStays
worldPositionStays If true, the parent-relative position, scale and rotation are modified such that the object keeps the same world space position, rotation and scale as before.
assigning a new
transform.parent = parentTransform;`
will always act the same way as
transform.SetParent(parentTransform);
since the default value for worldPositionStays (so if you don't explicitly pass it) is true.
So for the specific case of UI in a Canvas you could use
public TheSpawnComponent : MonoBehaviour
{
// Via the Inspector drag&drop any object here that is inside the canvas
// or the canvas itself
[SerializeField] private GameObject parentInCanvas;
[SerializeField] private Button buttonPrefab;
public void DoInstantiate()
{
var newButton = Instantiate (buttonPrefab, parentInCanvas);
//Todo Position and callback
}
}
Or if the spawner script is attached to an object inside the canvas anyway you could also spawn as child of this one directly using
var newButton = Instantiate(buttonPrefab, transform);
You can specify the transforms parent after you have created the game object.
spawnedObject.transform.parent = canvas.transform;
You have to use below code
public GameObject Prefab; // Object to Create
public Transform ParentOfObj;// Must Be inside the canvas or canvas it self
void Start()
{
GameObject g = Instantiate(Prefab) as GameObject;
g.transform.SetParent(ParentOfObj);
g.transform.localScale = Vector3.one;
}
Context
I'm working in a pickup system in my game. I've a component called AbstractSightCollider that has a sphere collider and some AbstractPickupableObject that are the objects meant to be picked up.
AbstractSightCollider is attached to the main character, but could be attached to any alive entity or anything that is able to contain inventory objects.
The way i designed it, it's that when AbstractSightCollider detects an object, it fires an UnityEvent called PickupDetected and when the player leaves the range of pickup, it call an UnityEvent called PickupLeave
The problem
I can't make OnCollisionEnter and OnCollisionExit trigger.
Some code
This is attached to AbstractSightCollider
public class AbstractObjectSight : MonoBehaviour
{
public OnPickupableDetected pickupDetected;
public OnPickupableLeave pickupLeave;
private void OnCollisionEnter(Collision col) {
GameObject gameObject = col.gameObject;
AbstractPickupableObject abstractPickupableObject =
gameObject.transform.GetComponent<AbstractPickupableObject>();
if (abstractPickupableObject != null) {
pickupDetected.Invoke(abstractPickupableObject);
}
}
private void OnCollisionExit(Collision col) {
GameObject gameObject = col.gameObject;
AbstractPickupableObject abstractInventoryObject =
gameObject.transform.GetComponent<AbstractPickupableObject>();
if (abstractInventoryObject != null) {
pickupLeave.Invoke(abstractInventoryObject);
}
}
[System.Serializable]
public class OnPickupableDetected : UnityEvent<AbstractPickupableObject> { }
[System.Serializable]
public class OnPickupableLeave : UnityEvent<AbstractPickupableObject> { }
}
And here are the properties:
Thanks for your time
Make sure both objects (the one with the script and the one that will cause the trigger) have colliders and rigidbodys, I find if one doesn't have those the triggers and collisions will not work.
I just found out the problem.
OnCollisionEnter and OnCollisionExit aren't the events that i needed to listen, because they work with rigidbody. My AbstractSight is that, a non body abstract sphere where the entities are allowed to grab items.
Instead, i used OnTriggerEnter, OnTriggerExit and now it works like a charm.
Rigid body on the parent object means the collider will work on ANY child component but the rigid body MUST be on the parent object.
Example:
MyProjectile has a rigid body and a collider - set isTrigger = true
MyEnemy parent object just holds scripts
MyEnemy childObject holds the enemy prefab including its collider,
Everything is set to isKinematic = true, with no gravity.
Everything works fine.