UGUI中的事件系统

1.UGUI中支持的事件

MSDN链接：https://docs.unity3d.com/Manual/SupportedEvents.html

参考博文：http://blog.csdn.net/lyh916/article/details/44570503

2. 实现事件有两种方式：

a).编辑器：添加EventTrigger组件

b).代码：继承EventTrigger实现所需要的事件

using  System.Collections;
using  System.Collections.Generic;
using  UnityEngine;
using  UnityEngine.EventSystems;

public  class  CubeState :  EventTrigger{

    //====================================================================================
    //其它系列:
    //OnSubmit、OnCancel、OnDrop、OnMove、OnScroll
    //====================================================================================

    //PC平台下按Enter键
    public  override  void  OnSubmit(BaseEventData eventData)
    {
        Debug.Log( "调用OnSubmit..." );
    }

    //PC平台下按ESC键
    public  override  void  OnCancel(BaseEventData eventData)
    {
        Debug.Log( "调用OnCancel..." );
    }

    //鼠标松开时
    public  override  void  OnDrop(PointerEventData eventData)
    {
        Debug.Log( "调用OnDrop..." );
    }

    //物体在移动时(未测试)
    public  override  void  OnMove(AxisEventData eventData)
    {
        Debug.Log( "调用OnMove..." );
    }

    //鼠标滚轮滚动的时候(未测试)
    public  override  void  OnScroll(PointerEventData eventData)
    {
        Debug.Log( "调用OnScroll..." );
    }



    //====================================================================================
    //Select系列:
    //OnSelect、OnUpdateSelected、OnDeselect
    //====================================================================================

    //当被选中的时候调用一次
    public  override  void  OnSelect(BaseEventData eventData)
    {
        Debug.Log( "调用OnSelect..." );
    }

    //在选中的时候每帧都会被调用
    public  override  void  OnUpdateSelected(BaseEventData eventData)
    {
        //Debug.Log("调用OnUpdateSelected...");
    }

    //物体从选中状态到取消选中状态时会被调用
    public  override  void  OnDeselect(BaseEventData eventData)
    {
        Debug.Log( "调用OnDeselect..." );
    }

    //====================================================================================
    //Pointer系列：
    //执行先后顺序:
    //OnPointerDown>OnPointerEnter>OnPointerClick>OnPointerUp>OnPointerExit
    //====================================================================================

    //初始化拖拽时
    public  override  void  OnInitializePotentialDrag(PointerEventData eventData)
    {
        Debug.Log( "调用OnInitializePotentialDrag..." );
    }

    //指针刚开始点击之后点击之后第一时间时
    public  override  void  OnPointerEnter(PointerEventData eventData)
    {
        Debug.Log( "调用OnPointerEnter..." );
    }

    //在同一个物体上点击
    public  override  void  OnPointerClick(PointerEventData eventData)
    {
        Debug.Log( "调用OnPointerClick..." );
    }

    //鼠标抬起
    public  override  void  OnPointerUp(PointerEventData eventData)
    {
        Debug.Log( "调用OnPointerUp..." );
    }

    //鼠标按下
    public  override  void  OnPointerDown(PointerEventData eventData)
    {
        Debug.Log( "调用OnPointerDown..." );
    }

    //结束的时候
    public  override  void  OnPointerExit(PointerEventData eventData)
    {
        Debug.Log( "调用OnPointerExit..." );
    }

    //====================================================================================
    //拖拽系列：
    //OnBeginDrag、OnDrag、OnEndDrag
    //====================================================================================

    //开始拖拽
    public  override  void  OnBeginDrag(PointerEventData eventData)
    {
        Debug.Log( "调用OnBeginDrag..." );
        //Debug.Log("pointerPress："+eventData.pointerPress);
        //Debug.Log("pressPosition；" + eventData.pressPosition);
        ChangePositionByDrag(eventData);
    }

    //拖拽过程中
    public  override  void  OnDrag(PointerEventData eventData)
    {
        //Debug.Log("调用OnDrag...");
        ChangePositionByDrag(eventData);
    }

    //结束拖拽
    public  override  void  OnEndDrag(PointerEventData eventData)
    {
        Debug.Log( "调用OnEndDrag..." );
        ChangePositionByDrag(eventData);
    }



    //拖过拖拽变更自身坐标
    void  ChangePositionByDrag(PointerEventData eventData) {
        var  rt = gameObject.GetComponent<RectTransform>();

        Vector3 globalMousePos;
        if  (RectTransformUtility.ScreenPointToWorldPointInRectangle(rt, eventData.position, eventData.pressEventCamera,  out  globalMousePos))
        {
            rt.position = globalMousePos;
        }
    }




}

3.将事件究极封装起来

using  UnityEngine;
using  System.Collections;
using  UnityEngine.EventSystems;

public  class  EventTriggerListener : EventTrigger {

    #region 变量
    //带参数是为了方便取得绑定了UI事件的对象
    public  delegate  void  PointerEventDelegate(GameObject go, PointerEventData eventData);
    public  delegate  void  BaseEventDelegate(GameObject go, BaseEventData eventData);
    public  delegate  void  AxisEventDelegate(GameObject go, AxisEventData eventData);

    public  event  PointerEventDelegate onPointerEnter;
    public  event  PointerEventDelegate onPointerExit;
    public  event  PointerEventDelegate onPointerDown;
    public  event  PointerEventDelegate onPointerUp;
    public  event  PointerEventDelegate onPointerClick;
    public  event  PointerEventDelegate onInitializePotentialDrag;
    public  event  PointerEventDelegate onBeginDrag;
    public  event  PointerEventDelegate onDrag;
    public  event  PointerEventDelegate onEndDrag;
    public  event  PointerEventDelegate onDrop;
    public  event  PointerEventDelegate onScroll;
    public  event  BaseEventDelegate onUpdateSelected;
    public  event  BaseEventDelegate onSelect;
    public  event  BaseEventDelegate onDeselect;
    public  event  AxisEventDelegate onMove;
    public  event  BaseEventDelegate onSubmit;
    public  event  BaseEventDelegate onCancel;
    #endregion

    public  static  EventTriggerListener GetListener(GameObject go)
    {
        EventTriggerListener listener = go.GetComponent<EventTriggerListener>();
        if  (listener ==  null ) listener = go.AddComponent<EventTriggerListener>();
        return  listener;
    }

    #region 方法
    public  override  void  OnPointerEnter(PointerEventData eventData)
    {
        if  (onPointerEnter !=  null ) onPointerEnter(gameObject, eventData);
    }
    public  override  void  OnPointerExit(PointerEventData eventData)
    {
        if  (onPointerExit !=  null ) onPointerExit(gameObject, eventData);
    }
    public  override  void  OnPointerDown(PointerEventData eventData)
    {
        if  (onPointerDown !=  null ) onPointerDown(gameObject, eventData);
    }
    public  override  void  OnPointerUp(PointerEventData eventData)
    {
        if  (onPointerUp !=  null ) onPointerUp(gameObject, eventData);
    }
    public  override  void  OnPointerClick(PointerEventData eventData)
    {
        if  (onPointerClick !=  null ) onPointerClick(gameObject, eventData);
    }
    public  override  void  OnInitializePotentialDrag(PointerEventData eventData)
    {
        if  (onInitializePotentialDrag !=  null ) onInitializePotentialDrag(gameObject, eventData);
    }
    public  override  void  OnBeginDrag(PointerEventData eventData)
    {
        if  (onBeginDrag !=  null ) onBeginDrag(gameObject, eventData);
    }
    public  override  void  OnDrag(PointerEventData eventData)
    {
        if  (onDrag !=  null ) onDrag(gameObject, eventData);
    }
    public  override  void  OnEndDrag(PointerEventData eventData)
    {
        if  (onEndDrag !=  null ) onEndDrag(gameObject, eventData);
    }
    public  override  void  OnDrop(PointerEventData eventData)
    {
        if  (onDrop !=  null ) onDrop(gameObject, eventData);
    }
    public  override  void  OnScroll(PointerEventData eventData)
    {
        if  (onScroll !=  null ) onScroll(gameObject, eventData);
    }
    public  override  void  OnUpdateSelected(BaseEventData eventData)
    {
        if  (onUpdateSelected !=  null ) onUpdateSelected(gameObject, eventData);
    }
    public  override  void  OnSelect(BaseEventData eventData)
    {
        if  (onSelect !=  null ) onSelect(gameObject, eventData);
    }
    public  override  void  OnDeselect(BaseEventData eventData)
    {
        if  (onDeselect !=  null ) onDeselect(gameObject, eventData);
    }
    public  override  void  OnMove(AxisEventData eventData)
    {
        if  (onMove !=  null ) onMove(gameObject, eventData);
    }
    public  override  void  OnSubmit(BaseEventData eventData)
    {
        if  (onSubmit !=  null ) onSubmit(gameObject, eventData);
    }
    public  override  void  OnCancel(BaseEventData eventData)
    {
        if  (onCancel !=  null ) onCancel(gameObject, eventData);
    }
    #endregion

}

调用：

using  UnityEngine;
using  System.Collections;
using  UnityEngine.EventSystems;

public  class  TestUI3 : MonoBehaviour {

    private  GameObject button;
    private  GameObject image;

    void  Start ()
    {
        button = GameObject.Find( "Button" );
        image = GameObject.Find( "Image" );
        EventTriggerListener.GetListener(button).onPointerClick += Click;
        EventTriggerListener.GetListener(image).onDrag += Drag;
    }

    public  void  Click(GameObject go)
    {
        Debug.Log(go.name);
    }

    public  void  Drag(GameObject go)
    {
        Debug.Log(go.name);
    }
}