unity2d如何实现当拖拽UI到正确位置后不能再被拖拽的代码

感谢您的提问！以下是您需要的代码：

using UnityEngine;
using UnityEngine.EventSystems;

public class DragAndDrop : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private Vector3 initialPosition;

    public void OnBeginDrag(PointerEventData eventData)
    {
        initialPosition = transform.position;
    }

    public void OnDrag(PointerEventData eventData)
    {
        transform.position = Input.mousePosition;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        float distance = Vector3.Distance(transform.position, initialPosition);
        if(distance < 50) // 50 为拖拽的容错距离
        {
            transform.position = initialPosition;
        }
        else
        {
            // 拖拽到正确位置后，禁止再次拖拽
            GetComponent<CanvasGroup>().blocksRaycasts = false;
        }
    }
}

当拖拽到正确位置后，代码会禁止再次拖拽。希望能够帮助您！