UGUI研究院之控件以及按钮的监听事件系统

继续学习，我相信大家在做NGUI开发的时候处理事件都会用到UIEventListener，那么UGUI中怎么办呢？先看UGUI的事件有那些吧

Supported Events

The Eventsystem supports a number of events, and they can be customised further in user custom user written InputModules.

The events that are supported by the StandaloneInputModule and TouchInputModule are provided by interface and can be implemented on a MonoBehaviour by implementing the interface. If you have a valid EventSystem configured the events will be called at the correct time.

IPointerEnterHandler – OnPointerEnter – Called when a pointer enters the object
IPointerExitHandler – OnPointerExit – Called when a pointer exits the object
IPointerDownHandler – OnPointerDown – Called when a pointer is pressed on the object
IPointerUpHandler – OnPointerUp – Called when a pointer is released (called on the original the pressed object)
IPointerClickHandler – OnPointerClick – Called when a pointer is pressed and released on the same object
IBeginDragHandler – OnBeginDrag – Called on the drag object when dragging is about to begin
IDragHandler – OnDrag – Called on the drag object when a drag is happening
IEndDragHandler – OnEndDrag – Called on the drag object when a drag finishes
IDropHandler – OnDrop – Called on the object where a drag finishes
IScrollHandler – OnScroll – Called when a mouse wheel scrolls
IUpdateSelectedHandler – OnUpdateSelected – Called on the selected object each tick
ISelectHandler – OnSelect – Called when the object becomes the selected object
IDeselectHandler – OnDeselect – Called on the selected object becomes deselected
IMoveHandler – OnMove – Called when a move event occurs (left, right, up, down, ect)
ISubmitHandler – OnSubmit – Called when the submit button is pressed
ICancelHandler – OnCancel – Called when the cancel button is pressed

OK 怎么样才能让UGUI监听的方式和NGUI差不多呢？ 这里我给大家引一个思路，把下面代码放在你的项目里。

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;
public class EventTriggerListener : UnityEngine.EventSystems.EventTrigger{
    public delegate void VoidDelegate (GameObject go);
    public VoidDelegate onClick;
    public VoidDelegate onDown;
    public VoidDelegate onEnter;
    public VoidDelegate onExit;
    public VoidDelegate onUp;
    public VoidDelegate onSelect;
    public VoidDelegate onUpdateSelect;
 
    static public EventTriggerListener Get (GameObject go)
    {
        EventTriggerListener listener = go.GetComponent<EventTriggerListener>();
        if (listener == null) listener = go.AddComponent<EventTriggerListener>();
        return listener;
    }
    public override void OnPointerClick(PointerEventData eventData)
    {
        if(onClick != null)     onClick(gameObject);
    }
    public override void OnPointerDown (PointerEventData eventData){
        if(onDown != null) onDown(gameObject);
    }
    public override void OnPointerEnter (PointerEventData eventData){
        if(onEnter != null) onEnter(gameObject);
    }
    public override void OnPointerExit (PointerEventData eventData){
        if(onExit != null) onExit(gameObject);
    }
    public override void OnPointerUp (PointerEventData eventData){
        if(onUp != null) onUp(gameObject);
    }
    public override void OnSelect (BaseEventData eventData){
        if(onSelect != null) onSelect(gameObject);
    }
    public override void OnUpdateSelected (BaseEventData eventData){
        if(onUpdateSelect != null) onUpdateSelect(gameObject);
    }
}

然后在你的界面里面写入监听按钮的代码。

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using UnityEngine.Events;
public class UIMain : MonoBehaviour {
    Button    button;
    Image image;
    void Start () 
    {
        button = transform.Find("Button").GetComponent<Button>();
        image = transform.Find("Image").GetComponent<Image>();
        EventTriggerListener.Get(button.gameObject).onClick =OnButtonClick;
        EventTriggerListener.Get(image.gameObject).onClick =OnButtonClick;
    }
 
    private void OnButtonClick(GameObject go){
        //在这里监听按钮的点击事件
        if(go == button.gameObject){
            Debug.Log ("DoSomeThings");
        }
    }
}

虽然还有一些别的监听方式，但是我觉得这种方式是最科学的，大家可根据自己项目的需求继续拓展EventTriggerListener类。

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