thanks for reading, I am working on a small memory card game in C# using Unity. When I run a certain scene I am receiving constant errors. The errors are as follows:
"NullReferenceException: Object reference not set to an instance of an object
Card.SetUpArt () (at Assets/Scripts/Card.cs:31)
Pairs.SetUpDeck () (at Assets/Scripts/Pairs.cs:62)
Pairs.Update () (at Assets/Scripts/Pairs.cs:23)"
My code is:
using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine;
public class Card : MonoBehaviour {
public static bool NO_TURN = false;
[SerializeField]
private int cardState; //state of card
[SerializeField]
private int cardNumber; //Card value (1-13)
[SerializeField]
private bool _setUp = false;
private Sprite cBack; //card back (Green square)
private Sprite cFace; //card face (1-10 JQKA)
private GameObject pairsManager;
void Begin()
{
cardState = 1; //cards face down
pairsManager = GameObject.FindGameObjectWithTag("PairsManager");
}
public void SetUpArt()
{
cBack = pairsManager.GetComponent<Pairs>().GetBack(); //<--error
cFace = pairsManager.GetComponent<Pairs>().GetFace(cardNumber);
turnCard();//turns the card
}
public void turnCard() //handles turning of card
{
if (cardState == 0)
{
cardState = 1;
}
else if(cardState == 1)
{
cardState = 0;
}
if (cardState == 0 && !NO_TURN)
{
GetComponent<Image>().sprite = cBack; // shows card back
}
else if (cardState == 1 && !NO_TURN)
{
GetComponent<Image>().sprite = cFace; // shows card front
}
}
//setters and getters
public int Number
{
get {return cardNumber;}
set { cardNumber = value;}
}
public int State
{
get { return cardState; }
set { cardState = value; }
}
public bool SetUp
{
get { return _setUp; }
set { _setUp = value; }
}
public void PairCheck()
{
StartCoroutine(pause ());
}
IEnumerator pause()
{
yield return new WaitForSeconds(1);
if (cardState == 0)
{
GetComponent<Image>().sprite = cBack;
}
else if (cardState == 1)
{
GetComponent<Image>().sprite = cFace;
}
}
}
And:
using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using UnityEngine;
public class Pairs : MonoBehaviour {
public Sprite[] cardFace; //array of card faces
public Sprite cardBack;
public GameObject[] deck; //array of deck
public Text pairsCount;
private bool deckSetUp = false;
private int pairsLeft = 13;
// Update is called once per frame
void Update () {
if (!deckSetUp)
{
SetUpDeck();
}
if (Input.GetMouseButtonUp(0)) //detects left click
{
CheckDeck();
}
}//Update
void SetUpDeck()
{
for(int i = 0; i <deck.Length; i++)//resets cards
{
deck[i].GetComponent<Card>().SetUp = false;
}
for (int ix = 0; ix < 2; ix++) //sets up cards twice,
{
for(int i = 1; i < 14; i++)//sets up card value (2-10 JQKA)
{
bool test = false;
int val = 0;
while (!test)
{
val = Random.Range(0, deck.Length);
test = !(deck[val].GetComponent<Card>().SetUp);
}//while
//sets up cards
deck[val].GetComponent<Card>().Number = i;
deck[val].GetComponent<Card>().SetUp = true;
}//nested for
}//for
foreach (GameObject crd in deck)
{
crd.GetComponent<Card>().SetUpArt();
}
if (!deckSetUp)
{
deckSetUp = true;
}
}//SetUpDeck
public Sprite GetBack()
{
return cardBack;
}//getBack
public Sprite GetFace(int i)
{
return cardFace[i - 1];
}//getFace
void CheckDeck()
{
List < int > crd = new List<int>();
for(int i = 0; i < deck.Length; i++)
{
if(deck[i].GetComponent<Card>().State == 1)
{
crd.Add(i);
}
}
if(crd.Count == 2)
{
CompareCards(crd);
}
}//CheckDeck
void CompareCards(List<int> crd)
{
Card.NO_TURN = true; //stops cards turning
int x = 0;
if(deck[crd[0]].GetComponent<Card>().Number ==
deck[crd[1]].GetComponent<Card>().Number)
{
x = 2;
pairsLeft--;
pairsCount.text = "PAIRS REMAINING: " + pairsLeft;
if(pairsLeft == 0) // goes to home screen when game has been won
{
SceneManager.LoadScene("Home");
}
}
for(int j = 0; j < crd.Count; j++)
{
deck[crd[j]].GetComponent<Card>().State = x;
deck[crd[j]].GetComponent<Card>().PairCheck();
}
}//CompareCards
}
Any help anyone can offer would be greatly appreciated. Thank you in advance. Link to GitHub Repository
