博主cc最近用UGUI實現了一個拼圖遊戲，類似於揹包系統（缺少揹包系統中資料部分），包含了物品的拖拉拽，物品交換等操作 物品交換操作原理：

1. 指令碼實現 IBeginDragHandler, IDragHandler, IEndDragHandler中的方法，進行物品移動的操作
2. 結束拖拽時，判斷滑鼠下面是否有物品，如果有就交換（交換父物體，並重置），否則物品歸回原位置
3. 難點：物品拖拽時，若其他物品先渲染，會遮擋住正在拖拽的物體；解決方法：拖拽時，將物體父級設定為Canvas，結束拖拽後再設為原父級。

ImageLoad：用來載入圖片

using UnityEngine;
using UnityEngine.
 
UI;
using System.Collections.Generic;

public class ImageLoad : MonoBehaviour
{
    public GameObject gridItemPrefab;
    private List<Item> itemList;

    void Start()
    {
        itemList = new List<Item>();
        InitItems();
    }

    //檢測是否遊戲成功
    private void OnItemEndDrag()
    {
 

        bool isSuccess = true;
        foreach (Item item in itemList)
        {
            if (item.IsPositionRight == false)
            {
                isSuccess = false;
                break;
            }
        }

        if (isSuccess)
        {
            Debug.Log("拼圖成功！");
        }
 

        else
        {
            Debug.Log("圖片還未拼成功！");
        }
    }

    private void InitItems()
    {
        Sprite[] imgArr = Resources.LoadAll<Sprite>("Image/testImg");

        int length = imgArr.Length;

        //儲存實際的realIndex
        int[] realIndexArr = new int[length];
        for (int i = 0; i < length; i++)
        {
            realIndexArr[i] = i;
        }

        //打亂順序
        for (int i = 0; i < length; i++)
        {
            int numRandom = Random.Range(0, length);
            Sprite tempSprite = imgArr[i];
            imgArr[i] = imgArr[numRandom];
            imgArr[numRandom] = tempSprite;

            int tempIndex = realIndexArr[i];
            realIndexArr[i] = realIndexArr[numRandom];
            realIndexArr[numRandom] = tempIndex;
        }

        for (int i = 0; i < length; i++)
        {
            Transform gridItem = GameObject.Instantiate(gridItemPrefab, transform).transform;
            Transform item = gridItem.Find("Item");
            item.tag = "ItemGrid";
            item.GetComponent<Image>().sprite = imgArr[i];
            Item tempItem = item.GetComponent<Item>();
            tempItem.SetIndex(realIndexArr[i], i);
            tempItem.AddEndDragListener(OnItemEndDrag);
            itemList.Add(tempItem);
        }
    }
}

Item：用來控制物品的交換

using UnityEngine;
using UnityEngine.EventSystems;
using System;

public class Item : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    private Vector3 offset;         //偏移量
    private Vector3 originPosition;  //拖拽前的位置
    private Transform canvasTransform;
    private Transform originParentTransform;   //父物件
    private CanvasGroup group;

    private int realIndex;  //實際的index
    [HideInInspector]
    public int curIndex;   //當前的index

    public bool IsPositionRight
    {
        get
        {
            if(realIndex != curIndex)
            {
                Debug.Log("實際位置：" + realIndex + "，當前位置：" + curIndex);
            }
            return realIndex == curIndex;
        }
    }

    private event Action EndDragEvent;

    void Awake()
    {
        canvasTransform = GameObject.Find("Canvas").transform;
        group = transform.GetComponent<CanvasGroup>();
    }

    public void SetIndex(int realIndex, int curIndex)
    {
        this.realIndex = realIndex;
        this.curIndex = curIndex;
    }

    public void AddEndDragListener(Action method)
    {
        EndDragEvent += method;
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        originParentTransform = transform.parent;
        offset = transform.position - Input.mousePosition;
        originPosition = transform.position;
        transform.SetParent(canvasTransform);
        group.blocksRaycasts = false;
    }

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

    public void OnEndDrag(PointerEventData eventData)
    {
        GameObject tempGameObject = eventData.pointerCurrentRaycast.gameObject;
        if (tempGameObject != null && tempGameObject.tag == "ItemGrid")
        {
            transform.SetParent(tempGameObject.transform.parent);

            tempGameObject.transform.SetParent(originParentTransform);
            tempGameObject.GetComponent<RectTransform>().anchoredPosition = Vector2.zero;

            Item tempItem = tempGameObject.GetComponent<Item>();

            int tempCurIndex = tempItem.curIndex;
            tempItem.curIndex = this.curIndex;
            this.curIndex = tempCurIndex;
        }
        else
        {
            transform.SetParent(originParentTransform);
        }
        transform.GetComponent<RectTransform>().anchoredPosition = Vector2.zero;
        group.blocksRaycasts = true;

        if (EndDragEvent != null)
        {
            EndDragEvent();
        }
    }

}