UGUI拖拽事件的实现

谁借莪１个温暖的怀抱￠ 2022-07-14 10:52 220阅读 0赞

UGUI 自带有拖拽事件,我们具体来实现看看,为了便于理解,我尽量去除不必要的代码.

第一步:继承3个接口:IBeginDragHandler,IDragHandler,IEndDragHandler,分别是拖拽开始,拖拽途中,拖拽结束.(实现相应方法)

using UnityEngine;
    using System.Collections;
    using UnityEngine.EventSystems;
    public class NeedMountScript : MonoBehaviour,IBeginDragHandler,IDragHandler,IEndDragHandler{
    
    
        public void OnBeginDrag(PointerEventData eventData){
    
            Debug.Log("开始拖拽");
        }
        public void OnDrag(PointerEventData eventData){
    
            Debug.Log(eventData.position);
        }
        public void OnEndDrag(PointerEventData eventData){
            Debug.Log("结束拖拽");
    
        }
    }

我们打印出 eventData.position,可以明白这个坐标就是屏幕坐标,左下角起始点(0,0)  
第二步:让 ui 跟随鼠标移动.

只需要3句话:

using UnityEngine;
    using System.Collections;
    using UnityEngine.UI;
    using UnityEngine.EventSystems;
    public class NeedMountScript : MonoBehaviour,IBeginDragHandler,IDragHandler,IEndDragHandler{
    
    
        public void OnBeginDrag(PointerEventData eventData){
    
            Debug.Log("开始拖拽");
        }
        public void OnDrag(PointerEventData eventData){
    
            Vector3 pos;
            RectTransformUtility.ScreenPointToWorldPointInRectangle(GetComponent<Image>().rectTransform,eventData.position,eventData.pressEventCamera,out pos);
    
            transform.position = pos;
    
        }
        public void OnEndDrag(PointerEventData eventData){
            Debug.Log("结束拖拽");
    
        }
    }

拖拽的时候不停更新 eventData.position 的位置,把他转成世界坐标,不停赋值给图片的 position 就行了,看看实际效果吧!

![这里写图片描述][SouthEast]

ps:不要忘了把脚本挂在 ui 上面额,既然实现了拖拽,那么下一篇就来实现虚拟摇杆吧.

[SouthEast]: /images/20220714/c96d4ed84f4c403080fee5a9b89c57c2.png