using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
public class DrongItem : MonoBehaviour,IBeginDragHandler,IDragHandler,IEndDragHandler
{
[Header("表示限制的区域")]
public RectTransform LimitContainer;
[Header("场景中Canvas")]
public Canvas canvas;
[Header("要移动的UI的RectTransform")]
public RectTransform UIRectTransform;
// 位置偏移量
private Vector3 offset = Vector3.zero;
// 最小、最大X、Y坐标
private float minX, maxX, minY, maxY;
private bool isOnDrag=false;
/// <summary>
/// 开始拖拽,需要设置射线检测true
/// </summary>
/// <param name="eventData"></param>
public void OnBeginDrag(PointerEventData eventData)
{
if (isOnDrag) return;
isOnDrag=true;
if (RectTransformUtility.ScreenPointToWorldPointInRectangle(UIRectTransform, Input.mousePosition, null, out Vector3 MousePos))
{
// 计算偏移量
offset = UIRectTransform.position - MousePos;
// 设置拖拽范围
SetDragRange();
}
}
/// <summary>
/// 拖拽中
/// </summary>
/// <param name="eventData"></param>
public void OnDrag(PointerEventData eventData)
{
if (isOnDrag)
{
// 将屏幕空间上的点转换为位于给定RectTransform平面上的世界空间中的位置
if (RectTransformUtility.ScreenPointToWorldPointInRectangle(UIRectTransform, Input.mousePosition, null, out Vector3 MousePos))
{
UIRectTransform.position = DragRangeLimit(MousePos + offset);
}
}
}
/// <summary>
/// 拖拽结束
/// </summary>
public void OnEndDrag(PointerEventData eventData)
{
Debug.Log("name=" + this.name);
isOnDrag=false;
}
/// <summary>
/// 设置最大、最小坐标
/// </summary>
void SetDragRange()
{
// 最小x坐标 = 容器当前x坐标 - 容器轴心距离左边界的距离 + UI轴心距离左边界的距离
minX = LimitContainer.position.x
- LimitContainer.pivot.x * LimitContainer.rect.width * canvas.scaleFactor
+ UIRectTransform.rect.width * canvas.scaleFactor * UIRectTransform.pivot.x;
// 最大x坐标 = 容器当前x坐标 + 容器轴心距离右边界的距离 - UI轴心距离右边界的距离
maxX = LimitContainer.position.x
+ (1 - LimitContainer.pivot.x) * LimitContainer.rect.width * canvas.scaleFactor
- UIRectTransform.rect.width * canvas.scaleFactor * (1 - UIRectTransform.pivot.x);
// 最小y坐标 = 容器当前y坐标 - 容器轴心距离底边的距离 + UI轴心距离底边的距离
minY = LimitContainer.position.y
- LimitContainer.pivot.y * LimitContainer.rect.height * canvas.scaleFactor
+ UIRectTransform.rect.height * canvas.scaleFactor * UIRectTransform.pivot.y;
// 最大y坐标 = 容器当前x坐标 + 容器轴心距离顶边的距离 - UI轴心距离顶边的距离
maxY = LimitContainer.position.y
+ (1 - LimitContainer.pivot.y) * LimitContainer.rect.height * canvas.scaleFactor
- UIRectTransform.rect.height * canvas.scaleFactor * (1 - UIRectTransform.pivot.y);
}
/// <summary>
/// 限制坐标范围
/// </summary>
/// <param name="pos"></param>
/// <returns></returns>
Vector3 DragRangeLimit(Vector3 pos)
{
pos.x = Mathf.Clamp(pos.x, minX, maxX);
pos.y = Mathf.Clamp(pos.y, minY, maxY);
return pos;
}
}