using UnityEngine;
using UnityEngine.EventSystems;
using System.Collections;
using System;
//ç»™ç©ºé—´æ·»åŠ ç›‘å¬äº‹ä»¶è¦å®žçŽ°çš„一些接å£
public class DragUI : MonoBehaviour, IPointerDownHandler, IDragHandler, IPointerUpHandler,
IEndDragHandler, IPointerEnterHandler, IPointerExitHandler
{
public RectTransform canvas; //得到canvasçš„uguiåæ ‡
private RectTransform imgRect; //得到图片的uguiåæ ‡
Vector2 offset = new Vector3(); //用æ¥å¾—åˆ°é¼ æ ‡å’Œå›¾ç‰‡çš„å·®å€¼
Vector3 imgReduceScale = new Vector3(1, 1, 1); //设置图片缩放
Vector3 imgNormalScale = new Vector3(1, 1, 1); //æ£å¸¸å¤§å°
// Use this for initialization
void Start()
{
imgRect = GetComponent();
}
//å½“é¼ æ ‡æŒ‰ä¸‹æ—¶è°ƒç”¨ 接å£å¯¹åº” IPointerDownHandler
public void OnPointerDown(PointerEventData eventData)
{
Vector2 mouseDown = eventData.position; //è®°å½•é¼ æ ‡æŒ‰ä¸‹æ—¶çš„å±å¹•åæ ‡
Vector2 mouseUguiPos = new Vector2(); //定义一个接收返回的uguiåæ ‡
//RectTransformUtility.ScreenPointToLocalPointInRectangle()：把å±å¹•åæ ‡è½¬åŒ–æˆuguiåæ ‡
//canvas：åæ ‡è¦è½¬æ¢åˆ°å“ªä¸€ä¸ªç‰©ä½“上，这里img父类是Canvas，我们就用Canvas
//eventData.enterEventCamera：这个事件是由哪个摄åƒæœºæ‰§è¡Œçš„
//out mouseUguiPos：返回转æ¢åŽçš„uguiåæ ‡
//isRect：方法返回一个bool值，判æ–é¼ æ ‡æŒ‰ä¸‹çš„ç‚¹æ˜¯å¦åœ¨è¦è½¬æ¢çš„物体上
bool isRect = RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas, mouseDown, eventData.enterEventCamera, out mouseUguiPos);
if (isRect) //如果在
{
//计算图片ä¸å¿ƒå’Œé¼ æ ‡ç‚¹çš„å·®å€¼
offset = imgRect.anchoredPosition - mouseUguiPos;
}
}
//å½“é¼ æ ‡æ‹–åŠ¨æ—¶è°ƒç”¨ å¯¹åº”æŽ¥å£ IDragHandler
public void OnDrag(PointerEventData eventData)
{
Vector2 mouseDrag = eventData.position; //å½“é¼ æ ‡æ‹–åŠ¨æ—¶çš„å±å¹•åæ ‡
Vector2 uguiPos = new Vector2(); //用æ¥æŽ¥æ”¶è½¬æ¢åŽçš„拖动åæ ‡
//和上é¢ç±»ä¼¼
bool isRect = RectTransformUtility.ScreenPointToLocalPointInRectangle(canvas, mouseDrag, eventData.enterEventCamera, out uguiPos);
if (isRect)
{
//设置图片的uguiåæ ‡ä¸Žé¼ æ ‡çš„uguiåæ ‡ä¿æŒä¸å˜
imgRect.anchoredPosition = offset + uguiPos;
}
}
//å½“é¼ æ ‡æŠ¬èµ·æ—¶è°ƒç”¨ å¯¹åº”æŽ¥å£ IPointerUpHandler
public void OnPointerUp(PointerEventData eventData)
{
offset = Vector2.zero;
}
//å½“é¼ æ ‡ç»“æŸæ‹–动时调用 å¯¹åº”æŽ¥å£ IEndDragHandler
public void OnEndDrag(PointerEventData eventData)
{
offset = Vector2.zero;
}
//å½“é¼ æ ‡è¿›å…¥å›¾ç‰‡æ—¶è°ƒç”¨ å¯¹åº”æŽ¥å£ IPointerEnterHandler
public void OnPointerEnter(PointerEventData eventData)
{
imgRect.localScale = imgReduceScale; //缩å°å›¾ç‰‡
}
//å½“é¼ æ ‡é€€å‡ºå›¾ç‰‡æ—¶è°ƒç”¨ å¯¹åº”æŽ¥å£ IPointerExitHandler
public void OnPointerExit(PointerEventData eventData)
{
imgRect.localScale = imgNormalScale; //回å¤å›¾ç‰‡
}
}