I am practicing with C # Lists in Unity and I have encountered a problem.
My test script, instantiates 5 prefabs which are added in a gameobject list. I then wrote a code that generates a random int and from that number moves the prefab instantiated with that index (indexof). Everything works correctly, but the method that moves and deletes the prefab is repeated for all the gameobjects in the scene with an index higher than the one chosen. I enclose the two scripts to better explain the problem. (I would need the unlist method to be done only once.
how can i solve this problem and remove one item from the list at a time? (one each time the button is pressed, not all as it is now. Thanks)
script:
NpcController: Added in each instantiated prefab
ListCOntroller: added in the scene.
public class ListCOntroller : MonoBehaviour
{
public GameObject cubePrefab;
private GameObject cubeInstance;
public static List<GameObject> cubeList = new List<GameObject> ();
public TextMeshProUGUI checkText;
public static event Action chooseNpc;
public static int randNpcValue;
int rand;
private void Start()
{
for(int i =0; i < 5; i++)
{
cubeInstance = Instantiate(cubePrefab, new Vector3(i, -2, 0), Quaternion.identity);
cubeList.Add(cubeInstance);
}
}
public void CheckListText()
{
checkText.text = "Npc in list: " + cubeList.Count.ToString();
}
public static void SelectRandomCube()
{
randNpcValue = Random.Range(0, cubeList.Count);
chooseNpc?.Invoke();
}
}
public class NpcController : MonoBehaviour
{
void Start()
{
ListCOntroller.chooseNpc += NpcEvent;
}
private void NpcEvent()
{
if (ListCOntroller.cubeList.IndexOf(gameObject) == ListCOntroller.randNpcValue)
{
transform.localPosition = new Vector3(transform.position.x, 2, 0);
DeleteFromList();
}
}
private void DeleteFromList()
{
ListCOntroller.cubeList.RemoveAt(ListCOntroller.randNpcValue);
Debug.Log($"Delete from list: {ListCOntroller.randNpcValue}");
}
}
the int random number generated in the attached images is: 2
Because events are executed one after another.
Let's say you have 3 NPCs: NPC0, NPC1, NPC2
Now the random number you choosen is 1, when NPC1's NpcEvent runs, ListCOntroller.cubeList.IndexOf(gameObject) is 1 which equals to the randNpcValue, and then NPC1 will be removed from the list.
Note that now the list has 2 items left: NPC0, NPC2. Next NPC2's NpcEvent runs in turn, at this time, ListCOntroller.cubeList.IndexOf(gameObject) is still 1 because the list has only 2 items, so NPC2 is also removed from the list.
A solution is you can change the randNpcValue to an invalid value when a NPC is removed.
if (ListCOntroller.cubeList.IndexOf(gameObject) == ListCOntroller.randNpcValue)
{
transform.localPosition = new Vector3(transform.position.x, 2, 0);
DeleteFromList();
ListCOntroller.randNpcValue = -2;
}
In addition to this answer in general I don't really see the purpose mixing the the logic into two different scripts.
You have one for storing a list and raising an event and the other one listens to the event and manipulates the stored list -> This doesn't sounds right.
You could as well simply do `why don't you pass a long the the according object into the event in the first place and rather do something like
public class ListCOntroller : MonoBehaviour
{
// Singleton instance
private static ListCOntroller _instance;
// Read-only getter
public static ListCOntroller Instance => _instance;
// pass in the target object reference instead of doing things index based
public event Action<GameObject> chooseNpc;
public GameObject cubePrefab;
// THIS is the list controller -> nobody else should be able to manipulate this list
private readonly List<GameObject> cubeList = new ();
public TextMeshProUGUI checkText;
private void Awake()
{
if(_instance && _instance != this)
{
Destroy(this);
return;
}
_instance = this;
}
private void Start()
{
for(int i =0; i < 5; i++)
{
cubeInstance = Instantiate(cubePrefab, new Vector3(i, -2, 0), Quaternion.identity);
cubeList.Add(cubeInstance);
}
}
public static void SelectRandomCube()
{
if(cubeList.Count == 0)
{
Debug.LogWarning("Trying to pick item from empty list");
return;
}
var randomIndex = Random.Range(0, cubeList.Count);
var randomItem = cubeList[randomIndex];
// remove from the list yourself instead of relying on others to work correctly
cubeList.RemoveAt(randomIndex);
// pass along the target object
chooseNpc?.Invoke(randomItem);
}
}
and then
public class NpcController : MonoBehaviour
{
void Start()
{
ListCOntroller.Instance.chooseNpc += NpcEvent;
}
private void NpcEvent(GameObject target)
{
// check if you are the target object
if (target == gameObject))
{
// adjust your position - you don't care about other NPCs or the existence of a list
transform.localPosition = new Vector3(transform.position.x, 2, 0);
}
}
}
Related
I am making a script for a unity project to destroy an instantiated clone if it collides with another clone, but since the Game Object (the clone) is declared in the start method and I cannot put it at the top I need to figure out how to destroy the clone if it collides with something else.
This is the error I get if I put it on top:
A field initializer cannot reference the non-static field, method, or property
Code:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class topbigspike : MonoBehaviour
{
public GameObject Flame;
// Start is called before the first frame update
void Start()
{
int a = 30;
int i = 0;
while (0 < a)
{
a--;
i++;
GameObject FlameClone = Instantiate(Flame);
FlameClone.transform.position = new Vector3(Random.Range(10, 2000), -3, 0);
}
}
void OnCollisionEnter2D(Collision2D col)
{
Destroy(FlameClone);
}
}
As the error message says, you cannot use Flame as field initializer. But you can still declare FlameClone as field (at the top, as you say) ) and initialize it in the Start method:
public class topbigspike : MonoBehaviour
{
public GameObject Flame;
public GameObject FlameClone; // <=== Declare here, as class field.
// Start is called before the first frame update
void Start()
{
int a = 30;
int i = 0;
while (0 < a)
{
a--;
i++;
FlameClone = Instantiate(Flame); // <=== Initialize here.
FlameClone.transform.position = new Vector3(Random.Range(10, 2000), -3, 0);
}
}
void OnCollisionEnter2D(Collision2D col)
{
Destroy(FlameClone);
}
}
As already mentioned you need to store it a field in order to access it from other methods.
However, seeing a while loop there instantiating multiple (30) instances a single field isn't enough anyway except you really want to only destroy the last created instance.
It should probably rather be e.g.
public class topbigspike : MonoBehaviour
{
public int amount = 30;
public GameObject Flame;
private GameObject[] flameInstances;
void Start()
{
flameInstances = new GameObject[amount];
for(var i = 0; i < amount; i++)
{
var flameInstance = Instantiate(Flame);
flameInsance.transform.position = new Vector3(Random.Range(10, 2000), -3, 0);
flameInstances[i] = flameInstance;
}
}
void OnCollisionEnter2D(Collision2D col)
{
foreach(var flameInstance in flameInstances)
{
Destroy(flameInstance);
}
}
}
I am trying to call a method from the script Dice and after that method is executed the value of the variable diceValue will change. This is the value that I want to take and use in the method from the script Levizja.
Levizja.cs
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Levizja : MonoBehaviour
{
public Transform[] lojtaret;
public GameObject zari;
private int numer = 0;
public Dice vleraEzarit;
void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
GetComponent<Rigidbody>().AddForceAtPosition(new Vector3(Random.Range(0, 500), Random.Range(0, 500) * 10, Random.Range(0, 500)), new Vector3(0, 0, 0), ForceMode.Force);
Debug.Log("U hodh zari me numer: " + Dice.getValue());
}
}
}
Dice.cs
using System.Collections.Generic;
using UnityEngine;
public class Dice : MonoBehaviour
{
Rigidbody rb;
bool hasLanded, thrown;
Vector3 initPosition;
[SerializeField] private static int diceValue;
private static int numriLojtareve;
//public int diceValue;
public DiceSides[] diceSides;
void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
Reset();
RollDice();
}
if (rb.IsSleeping() && !hasLanded && thrown)
{
hasLanded = true;
rb.useGravity = false;
rb.isKinematic = true;
SideValueCheck();
}
else if (rb.IsSleeping() && hasLanded && diceValue == 0)
RollAgain();
}
void SideValueCheck()
{
diceValue = 0;
foreach(DiceSides side in diceSides)
{
if (side.OnGround())
{
diceValue = side.getValue();
Debug.Log(diceValue + " has been rolled!");
}
}
}
public static int getValue()
{
return diceValue;
}
}
Some of the methods are not included just to address only the issue.
I want to execute the Update method in Dice.cs which will call SideValueCheck method. This way the variable diceValue will be updated. After that I want the Update method in Levizja.cs to execute this way the new value will be stored there.
What happens is the first time I get the value 0 and the next run I get the last value that dice had. So if first time it landed 3 it shows 0. Next time it lands 2 it shows 3 and so on.
You could adjust this in the Script Execution Order and force a certain order of the executions of the same event message type (Update in this case).
However, this won't be enough. You rather want to wait until the dice has a result.
So before/instead of touching the execution order I would rather rethink the code structure and do something else. E.g. why do both your scripts need to check the user input individually?
Rather have one script call the methods of the other one event based. There is also no reason to have things static here as you already have a reference to an instance of a Dice anyway in vleraEzarit
public class Dice : MonoBehaviour
{
[Header("References")]
[SerializeField] private Rigidbody _rigidbody;
[SerializeField] private DiceSides[] diceSides;
[Header("Debug")]
[SerializeField] private int diceValue;
private bool hasLanded, thrown;
private Vector3 initPosition;
private int numriLojtareve;
// if you still also want to also provide a read-only access
// to the current value
public int DiceValue => diceValue;
// Event to be invoked everytime there is a new valid dice result
public event Action<int> OnHasResult;
private void Awake()
{
if(!_rigidbody)
{
_rigidbody = GetComponent<Rigidbody>();
}
}
private void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
Reset();
RollDice();
}
if (_rigidbody.IsSleeping() && !hasLanded && thrown)
{
hasLanded = true;
_rigidbody.useGravity = false;
_rigidbody.isKinematic = true;
SideValueCheck();
}
else if (_rigidbody.IsSleeping() && hasLanded && diceValue == 0)
{
RollAgain();
}
}
void SideValueCheck()
{
foreach(DiceSides side in diceSides)
{
if (side.OnGround())
{
diceValue = side.getValue();
Debug.Log(diceValue + " has been rolled!");
// Invoke the event and whoever is listening to it will be informed
OnHasResult?.Invoke(diceValue);
// also I would return here since i makes no sense to continue
// checking the other sides if you already have a result
return;
}
}
// I would move this here
// In my eyes it is clearer now that this is the fallback case
// and only happening if nothing in the loop matches
diceValue = 0;
}
}
And then make your Levizja listen to this event and only act once it is invoked like e.g.
public class Levizja : MonoBehaviour
{
[Header("References")]
[SerializeField] private Rigidbody _rigidbody;
[SerializeField] private Transform[] lojtaret;
[SerializeField] private GameObject zari;
[SerializeField] private Dice vleraEzarit;
private int numer = 0;
private void Awake()
{
if(!_rigidbody)
{
_rigidbody = GetComponent<Rigidbody>();
}
// Attach a callback/listener to the event
// just out of a habit I usually remove it first to make sure it can definitely only be added once
vleraEzarit.OnHasResult -= HandleDiceResult;
vleraEzarit.OnHasResult += HandleDiceResult;
}
private void OnDestroy()
{
// make sure to remove callbacks once not needed anymore
// to avoid exceptions
vleraEzarit.OnHasResult -= HandleDiceResult;
}
// This is called ONCE everytime the dice has found a new result
private void HandleDiceResult(int diceValue)
{
_rigidbody.AddForceAtPosition(new Vector3(Random.Range(0, 500), Random.Range(0, 500) * 10, Random.Range(0, 500)), new Vector3(0, 0, 0), ForceMode.Force);
Debug.Log("U hodh zari me numer: " + Dice.getValue());
}
}
Ideally the diceValue should be returned by the method and Dice should not have a state. If you absolutely need Dice to have a state then it should not be static.
I am at begginner level with unity.
I have Load() function that goes off in OnApplicationPause(false). It works fine if I block the screen or minimalise app, and come back to it. However, when I kill it, I get error and the data doesnt get loaded.
Below is the script attached to the GameObject "SaveManager"
using System.Collections.Generic;
using UnityEngine;
using System;
public class SaveManager : MonoBehaviour
{
public GameObject ZwierzetaGroup;
public GameObject JedzeniaGroup;
public GameObject PrzedmiotyGroup;
public List<GameObject> zwierzeta_sprites;
public List<GameObject> jedzenia_sprites;
public List<GameObject> przedmioty_sprites;
public static DateTime oldDate;
Camera mainCamera;
public SaveState saveState;
void Start()
{
mainCamera = Camera.main;
FillArrays();
}
public void Save()
{
Debug.Log("Saving.");
SaveSpriteArray("zwierze", zwierzeta_sprites);
SaveSpriteArray("przedmiot", przedmioty_sprites);
SaveSpriteArray("jedzenie", jedzenia_sprites);
PlayerPrefs.SetInt("pieniazki", saveState.GetPieniazki());
PlayerPrefs.SetInt("HayAmount", saveState.GetHayAmount());
PlayerPrefs.SetInt("HayMax", saveState.GetHayMax());
PlayerPrefs.SetInt("FruitAmount", saveState.GetFruitAmount());
PlayerPrefs.SetInt("FruitMax", saveState.GetFruitMax());
//time:
PlayerPrefs.SetString("sysString", System.DateTime.Now.ToBinary().ToString());
PlayerPrefs.SetInt("First", 1);
}
public void SaveSpriteArray(string saveName, List<GameObject> sprites)
{
for (int i = 0; i < sprites.Count; i++)
{
if (sprites[i].activeSelf)
{
PlayerPrefs.SetInt(saveName + i, 1);
}
else
{
PlayerPrefs.SetInt(saveName + i, 0);
}
}
}
public void Load()
{
Debug.Log("Loading.");
//wczytanie czasu:
long temp = Convert.ToInt64(PlayerPrefs.GetString("sysString"));
oldDate = DateTime.FromBinary(temp);
Debug.Log("oldDate: " + oldDate);
//wczytywanie aktywnych sprite'ow
LoadSpriteArray("zwierze", zwierzeta_sprites);
LoadSpriteArray("przedmiot", przedmioty_sprites);
LoadSpriteArray("jedzenie", jedzenia_sprites);
saveState.SetPieniazki(PlayerPrefs.GetInt("pieniazki"));
saveState.SetHayAmount(PlayerPrefs.GetInt("HayAmount"));
saveState.SetHayMax(PlayerPrefs.GetInt("HayMax"));
saveState.SetFruitAmount(PlayerPrefs.GetInt("FruitAmount"));
saveState.SetFruitMax(PlayerPrefs.GetInt("FruitMax"));
mainCamera.GetComponent<UpdateMoney>().MoneyUpdate();
}
public void LoadSpriteArray(string saveName, List<GameObject> sprites)
{
for (int i = 0; i < sprites.Count; i++)
{
if (PlayerPrefs.GetInt(saveName + i) == 1)
{
sprites[i].SetActive(true);
}
else
{
sprites[i].SetActive(false);
}
}
}
private void FillArrays()
{
//find children
foreach (Transform child in ZwierzetaGroup.transform)
{
zwierzeta_sprites.Add(child.gameObject);
}
foreach (Transform child in PrzedmiotyGroup.transform)
{
przedmioty_sprites.Add(child.gameObject);
}
foreach (Transform child in JedzeniaGroup.transform)
{
jedzenia_sprites.Add(child.gameObject);
}
}
}
Below is a chunk of script attached to the main camera (probably a mistake). SaveManager GameObject with Script is attached to this one in inspector. This script is pretty big, so I'll skip the parts that I don't find relevant.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;
public class ManageEncouters: MonoBehaviour
{
DateTime currentDate;
public int First;
public SaveState saveState;
public SaveManager saveManager;
public HayBar hayBar;
public FruitBar fruitBar;
public GameObject[] jedzenia_sprites;
void Start()
{
}
void OnApplicationPause(bool pauseStatus)
{
if (!pauseStatus)
{
currentDate = System.DateTime.Now;
//Sprawdzanie czy jest to piersze uruchomienie gry (brak zapisu)
First = PlayerPrefs.GetInt("First");
if (First == 0)
{
Debug.Log("First time in app.");
RandomiseAnimals();
SaveManager.oldDate = currentDate;
hayBar.SetHayMax(1);
hayBar.SetHay(0);
fruitBar.SetFruitMax(1);
fruitBar.SetFruit(0);
saveState.SetPieniazki(100);
this.GetComponent<UpdateMoney>().MoneyUpdate();
}
else
{
Debug.Log("Not the first time in app.");
saveManager.Load();
}
if (TimeInSeconds(currentDate, SaveManager.oldDate) > 12)
{
Debug.Log("It's been more than 12 seconds sience last time.");
EatFood(currentDate, SaveManager.oldDate);
RandomiseAnimals();
}
else
{
Debug.Log("It's been less than 12 seconds sience last time.");
}
}
if (pauseStatus)
{
saveManager.Save();
}
}
private int TimeInSeconds(DateTime newD, DateTime oldD)
{
TimeSpan difference = newD.Subtract(oldD);
int seconds = (int)difference.TotalSeconds;
return seconds;
}
}
Below is the error I get, I don't know how to copy the text, so it's an Image.
I'm pretty sure that what you have here is a timing issue.
OnApplicationPause
Note: MonoBehaviour.OnApplicationPause is called as a GameObject starts. The call is made after Awake. Each GameObject will cause this call to be made.
So to me this sounds like it might be called when your SaveManager is not yet initialized, in particular the mainCamera.
I think you could already solve the issue by moving the initialization into Awake instead
private void Awake()
{
mainCamera = Camera.main;
FillArrays();
}
In general my little thumb rule is
use Awake wherever possible. In particular initialize everything where you don't depend on other scripts (initialize fields, use GetComponent, etc)
use Start when you need other scripts to be initialized already (call methods on other components, collect and pass on instances of some prefabs spawned in Awake, etc)
This covers most of cases. Where this isn't enough you would need to bother with the execution order or use events.
I'm trying to make an array or a list with the first childs of a GameObject so I can edit them from another scripts.
I have tried it doing an Array, but it will take the childs of this childs too and I need to take only the first ones.
I have tried also with a List with a foreach, but it will add the same element every frame to the list, and I only need it one time.
public GameObject GOGranjaTerrain;
public GameObject GOFabricaTerrain;
public GameObject GOOficinaTerrain;
public Transform[] granjaTerrainArray;
public Transform[] fabricaTerrainArray;
public Transform[] oficinaTerrainArray;
public List<Transform> granjaTerrainList = new List<Transform>();
void Update()
{
SearchTerrains1();
SearchTerrains2();
}
//Array way
void SearchTerrains1()
{
granjaTerrainArray = GOGranjaTerrain.GetComponentsInChildren<Transform>();
fabricaTerrainArray = GOFabricaTerrain.GetComponentsInChildren<Transform>();
oficinaTerrainArray = GOOficinaTerrain.GetComponentsInChildren<Transform>();
}
//List way
void SearchTerrains2()
{
foreach(Transform child in GOGranjaTerrain.transform)
{
granjaTerrainList.Add(child);
}
}
Here's how you can do it:
void Update()
{
for (int i = 0; i < GOGranjaTerrain.transform.childCount; i++)
{
Transform child = GOGranjaTerrain.transform.GetChild(i);
if (granjaTerrainList.Contains(child) == false)
{
granjaTerrainList.Add(child);
}
}
}
Or even better, if you only need to do it once - do in in Start instead of Update.
I've been stuck on this script for about some weeks. I have this script where as to the items that are on a list shuffle every time a new game starts. I don't know why but I can't seem to shuffle an item list at all. Please help, and tested it for yourself if you can. Also please explain to me what might be the problem or what I can do to fix it, I'm still pretty new to this.
`using UnityEngine;
using System.Collections;
using System.Collections.Generic;
public class RayCasting : MonoBehaviour
{
public float pickupDistance;
public List<Item> items;
public List<Item> finalItems;
#region Unity
void Start ()
{
Screen.lockCursor = true;
// Do a while loop until finalItems contains 5 Items
while (finalItems.Count < 5) {
Item newItem = items[Random.Range(0, items.Count)];
if (!finalItems.Contains(newItem)) {
finalItems.Add(newItem);
}
items.Clear();
}
}
void Update ()
{
RaycastHit hit;
Ray ray = new Ray(transform.position, transform.forward);
if (Physics.Raycast(ray, out hit, pickupDistance))
{
foreach(Item item in finalItems)
{
if(Input.GetMouseButtonDown(0)) {
if (item.gameObject.Equals(hit.collider.gameObject))
{
numItemsCollected++;
item.Collect();
break;
}
}
}
}
}
void OnGUI()
{
GUILayout.BeginArea(new Rect(130,400,100,130));
{
GUILayout.BeginVertical();
{
if (numItemsCollected < items.Count)
{
foreach (Item item in finalItems)
GUILayout.Label(string.Format("[{0}] {1}", items.Collected ? "" + items.password: " ", items.name ));
}
else
{
GUILayout.Label("You Win!");
}
}
GUILayout.EndVertical();
}
GUILayout.EndArea();
}
#endregion
#region Private
private int numItemsCollected;
#endregion
}
[System.Serializable]
public class Item
{
public string name;
public GameObject gameObject;
public int password;
public bool Collected { get; private set; }
public void Collect()
{
Collected = true;
gameObject.SetActive(false);
}
public void passwordNumber()
{
password = 0;
Collected = true;
gameObject.SetActive(false);
}
}
`
This example is too complicated, and has a lot of unrelated code to the question you seem to be asking. As a basic strategy, you should try to isolate the code you think has a problem, fix that problem, then apply it to the larger case.
For example, your basic logic has at least one error: Random.Range is inclusive, so you could possibly have an out-of-bounds index unless you use "index.Count-1".
Here's an example that creates a list of 5 random items from a larger "original" list. You should be able to apply this to your code:
using UnityEngine;
using System.Collections.Generic;
public class RandomList : MonoBehaviour {
public List <int> originals = new List<int>();
public List <int> randomized = new List<int>();
public int desiredNumberOfRandomInts = 5;
// Use this for initialization
void Awake () {
for(int i = 1; i <= 20; ++i) {
originals.Add(i);
}
while(randomized.Count < desiredNumberOfRandomInts) {
int randomSelection = originals[Random.Range(0, originals.Count-1)];
if (!randomized.Contains(randomSelection)) {
randomized.Add(randomSelection);
}
}
}
}
I think removing the items.Clear() might work, with the reason I explained in my comment.
while (finalItems.Count < 5) {
Item newItem = items[Random.Range(0, items.Count)];
if (!finalItems.Contains(newItem)) {
finalItems.Add(newItem);
}
}
But still, I'm assuming you already have list of items somewhere already (and the list must be >5 since you will loop minimum 5 times). If you don't items.Count will still stay 0, and making your random become Random.Range(0,0).