unity小技巧:实现物品拖拽,位置交换,背包换格的效果
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
public class MoveItem : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
//记录玩家开始拖拽时的位置
private Vector3 vector;
//需要移动物品的位置组件
private RectTransform rectTransform;
//UI事件管理器
private EventSystem _EventSystem;
private GraphicRaycaster gra;
private void Awake()
{
_EventSystem = FindObjectOfType<EventSystem>();
gra = FindObjectOfType<GraphicRaycaster>();
rectTransform = GetComponent<RectTransform>();
}
/// <summary>
/// 开始拖拽时执行一次
/// </summary>
/// <param name="eventData"></param>
public void OnBeginDrag(PointerEventData eventData)
{
vector = this.transform.position;
}
/// <summary>
/// 拖拽时持续调用
/// </summary>
/// <param name="eventData"></param>
public void OnDrag(PointerEventData eventData)
{
this.rectTransform.anchoredPosition += eventData.delta;
}
/// <summary>
/// 结束拖拽时执行一次
/// </summary>
/// <param name="eventData"></param>
public void OnEndDrag(PointerEventData eventData)
{
//判断是否拖拽到格子上
bool isSolt = false;
//保存格子的位置
Vector3 SlotVector = new Vector3();
//通过定义的读取方法读取鼠标所在位置的UI对象
var list = GraphicRaycaster(Input.mousePosition);
foreach (var item in list)
{
//检测是否在物品上
if (item.gameObject.tag == "Item")
{
//如果在物品上则执行以下代码
//---交换位置---//
this.rectTransform.position = item.gameObject.transform.position;
item.gameObject.transform.position = vector;
}
//检测是否在格子上
else if(item.gameObject.tag == "Slot")
{
//如果在格子上则将isSlot设置为true方便后续代码
isSolt = true;
//保存格子位置坐标以便切换位置
SlotVector = item.gameObject.transform.position;
}
}
//判断是否检测在格子上
if (isSolt)
{
//如果在格子上,则切换到格子上
this.rectTransform.position = SlotVector;
}
else
{
//如果不在格子上,则返回原位置
this.rectTransform.position = vector;
}
}
/// <summary>
/// 定义通过射线读取所在位置的UI对象
/// </summary>
/// <param name="pos">射线位置</param>
/// <returns>返回读取的所有UI对象</returns>
private List<RaycastResult> GraphicRaycaster(Vector2 pos)
{
var mPointerEventData = new PointerEventData(_EventSystem);
mPointerEventData.position = pos;
List<RaycastResult> results = new List<RaycastResult>();
gra.Raycast(mPointerEventData, results);
return results;
}
}
