prefab对象不会返回正确的父对象。

Question

我正在做TCG (交易纸牌游戏)项目，并且正在为卡片进行拖动，除了卡片预制件应该返回的父程序外，它都是工作的。在编辑器中，它显示卡片预置返回到主屏幕，即使它应该返回到player1hand区域的原始位置，C#代码中没有显示错误，但是在整体余弦中有一个错误。

下面是编辑器控制台中的error

在这里输入图像描述

下面是CardController类

public class CardController : MonoBehaviour, IPointerDownHandler, IPointerUpHandler,IDragHandler {
//creating a special variable with card type 
public Card card;
//creating a 2 variables with Image type for the card sprite and playerhand background
public Image character, image;
//creating a 3 variables with TextMeshProUGUI type for the card stats
public TextMeshProUGUI cardName, attack, defence, level, description;
//dont know what to write plz help
private Transform originalParent;

//dont know what to write plz help
private void Awake()
{
    image = GetComponent<Image>();
}

//assgining the data from Card class to this class
public void Initialize(Card card)
{
    this.card = card;
    character.sprite = card.character;
    cardName.text = card.cardName;
    attack.text = card.attack.ToString();
    defence.text = card.defence.ToString();
    level.text = card.level.ToString();
    description.text = card.description;
    originalParent = transform.parent;
}

//what should happen when releasing the card
public void OnPointerUp(PointerEventData eventData)
{
    //dont know what to write plz help
    image.raycastTarget = true;
    //returning the card to his original position
    transform.SetParent(originalParent);
    //to center the card in the middle of the parent
    transform.localPosition = Vector3.zero;
}

//what should happen when holding the card
public void OnPointerDown(PointerEventData eventData)
{
    //changing the position of the card when holding left click
    transform.SetParent(transform.root);
    //dont know what to write plz help
    image.raycastTarget = false;
}

//what should happen when dragging the card
public void OnDrag(PointerEventData eventData)
{
    //changing the position of the card to the new position of the mouse while holding left click
    transform.position = eventData.position;
}}

这是CardManager类

public class CardManager : MonoBehaviour {
// making CardManager class gobal to access
public static CardManager instance;
// to create a list of cards
public List<Card> cards = new List<Card>();
// to declare the place where cards are summoned
public Transform player1Hand, player2Hand;
// creating a cardControllerPrefab varible to hold the CardPrefab from the editor
public CardController cardControllerPrefab;

//summoning CardController class in CardManager class
private void Awake()
{
    instance = this;

}

//to start the GenerateCard function when the game starts
private void Start()
{
    GenerateCards();
}

//to generate the cards using foreach loop and putting them in place
private void GenerateCards()
{
    foreach(Card card in cards)
    {
        //to create a new card using CardController class and putting it in CardControllerPrefab 
        CardController newCard = Instantiate(cardControllerPrefab, player1Hand);
        //to put the card in the player1Hand Area
        newCard.transform.localPosition = Vector3.zero;
        //to actavite the Card data class using a code in the CardController class
        newCard.Initialize(card);
    }
}}

如果你也能帮我改进我的评论，我会很感激的

Answer 1

当Unity遇到异常时，它会在当前方法上运行，但在其他情况下将继续运行(而不是崩溃到桌面)。

您还没有告诉我们第25行的内容，但是它阻止了您的代码进入下面一行：

originalParent = transform.parent;

您不能设置它(因为当您在第25行上命中错误时会中止)，所以当您使用它时它是空的。但是，空转换父函数是一个完全有效的选项--它意味着转换没有父级(并且应该是根级游戏对象)。

最好的建议是修复空引用异常，但如果做不到这一点，就可以将originalParent行移到Initialize方法的顶部。

Answer 2

Unity获得父对象：

     GameObject fu = this.transform.parent.gameObject; //Get the parent object of the current object
     GameObject fufu = fu.transform.parent.gameObject;// Get the parent object of the specified object

希望它能帮到你。