UGUI实现NGUI的UIEventListener功能

原文链接:http://www.tiankengblog.com/?p=45

在unity中处理UI事件时，习惯了使用NGUI的UIEventListener，虽然UGUI也有AddListener，但是一个组件只能对应一个函数，不能在一个函数中同时处理多个事件，显得有些麻烦

因为主要平时Button用得比较多，这里以UGUI的Button为例，自己以UGUI的Button的AddListener模仿NGUI的UIEventListener做了一个小封装，能在一个函数处理多个Button

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class UGUIButtonEventListener : MonoBehaviour {

public delegate void VoidDelegate(GameObject go);

public VoidDelegate onClick;

public static UGUIButtonEventListener GetClick(Button btn)
{
UGUIButtonEventListener listener = btn.GetComponent<UGUIButtonEventListener>();
if (listener == null)
listener = btn.gameObject.AddComponent<UGUIButtonEventListener>();
btn.onClick.AddListener(listener.OnClick);
return listener;
}

void OnClick()
{
if (onClick != null)
onClick(gameObject);
}
}

测试代码：

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

public class test : MonoBehaviour
{
public Button[] btns;
void Start()
{
for (int i = 0; i < btns.Length; i++)
UGUIButtonEventListener.Get(btns[i]).onClick = OnClick;
}

void OnClick(GameObject go)
{
print("name:"+go.name);
}
}

还有人给了另一个Button事件监听的方法，感觉也挺好用

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

public class test : MonoBehaviour
{
public Button[] btns;
void Start()
{
for (int i = 0; i < btns.Length; i++)
{
GameObject btnObj=btns[i].gameObject;
btns[i].onClick.AddListener(delegate(){OnClick(btnObj);});
}
}

void OnClick(GameObject go)
{
print("name:"+go.name);
}
}

但是UI事件肯定不止Button的Click事件，如果所有事件都按照上面的方法来封装就显得有些杂乱了。所以自己再去看了看UGUI的一些事件接口，发现通过实现接口，就能封装了，比如IPointerClickHandler，可以实现Click事件，IPointerEnterHandler、IPointerExitHandler可以实现Hover事件。后来再在网上查了一些资料，发现了EventTrigger已经继承了所有接口，正好可以用来封装UIEventListener

实现代码如下:

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

public class UGUIEventListener:EventTrigger
{
public delegate void VoidDelegate(GameObject go);
public delegate void BoolDelegate(GameObject go, bool isValue);
public delegate void FloatDelegate(GameObject go, float fValue);
public delegate void IntDelegate(GameObject go, int iIndex);
public delegate void StringDelegate(GameObject go, string strValue);

public VoidDelegate onSubmit;
public VoidDelegate onClick;
public BoolDelegate onHover;
public BoolDelegate onToggleChanged;
public FloatDelegate onSliderChanged;
public FloatDelegate onScrollbarChanged;
public IntDelegate onDrapDownChanged;
public StringDelegate onInputFieldChanged;

public override void OnSubmit(BaseEventData eventData)
{
if (onSubmit != null)
onSubmit(gameObject);
}
public override void OnPointerEnter(PointerEventData eventData)
{
if (onHover != null)
onHover(gameObject, true);
}
public override void OnPointerClick(PointerEventData eventData)
{
if (onClick != null)
onClick(gameObject);
if (onToggleChanged != null)
onToggleChanged(gameObject, gameObject.GetComponent<Toggle>().isOn);

}
public override void OnPointerExit(PointerEventData eventData)
{
if (onHover != null)
onHover(gameObject, false);
}
public override void OnDrag(PointerEventData eventData)
{
if (onSliderChanged != null)
onSliderChanged(gameObject, gameObject.GetComponent<Slider>().value);
if (onScrollbarChanged != null)
onScrollbarChanged(gameObject, gameObject.GetComponent<Scrollbar>().value);

}
public override void OnSelect(BaseEventData eventData)
{
if (onDrapDownChanged != null)
onDrapDownChanged(gameObject, gameObject.GetComponent<Dropdown>().value);
}
public override void OnUpdateSelected(BaseEventData eventData)
{
if (onInputFieldChanged != null)
onInputFieldChanged(gameObject, gameObject.GetComponent<InputField>().text);
}
public override void OnDeselect(BaseEventData eventData)
{
if (onInputFieldChanged != null)
onInputFieldChanged(gameObject, gameObject.GetComponent<InputField>().text);
}

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

测试代码如下:

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

public class test : MonoBehaviour
{
public Button[] btns;
public Scrollbar scrollbar;
void Start()
{
for (int i = 0; i < btns.Length; i++)
UGUIEventListener.Get(btns[i].gameObject).onClick = OnClick;
UGUIEventListener.Get(scrollbar.gameObject).onScrollbarChanged = OnScrollbarChanged;
}

void OnClick(GameObject go)
{
print("name:"+go.name);
}

void OnScrollbarChanged(GameObject go, float value)
{
print("name:" + go.name + "  value:" + value);
}
}

最后，还有一个小东西，因为自己在做一些测试的时候，发现UGUI的点击事件与3D物体的射线碰撞，是会发生冲突的，理论上，自己在点击UI的时候，3D物体的射线碰撞检测就会取消，不能让他们同时响应,这里用一个函数就可以判断EventSystem.current.IsPointerOverGameObject()

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

public class test : MonoBehaviour
{
void Update()
{
if (EventSystem.current.IsPointerOverGameObject())
Debug.Log("鼠标在UI上");
else
Debug.Log("鼠标没在UI上");
}
}