UGUI事件监听总结

Unity3D的uGUI系统的将UI可能触发的事件分为12个类型，即EventTriggerType枚举的  12个值。如下图所示：

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  

IInitializePotentialDragHandler - OnInitializePotentialDrag - Called when a drag target is found, can be used to initialise values  

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

  先以PointerClick为例。这个是用于某点点击事件。其他事件都可以根据相同的办法调用。

    之所以使用PointerClick为例。是因为在最后笔者会提到一个特殊的实现方式。而相比于其他事件类型，有且仅有Click事件存在特殊实现。

    我们要实现事件主要有3种方式：

    方式一：继承基础接口实现

    步骤一：创建ClickObject脚本。继承MonoBehaviour和IPointerClickHandler。

    

    步骤二：实现public void OnPointerClick(PointerEventData eventData)方法：

    步骤三：创建一个名为Panel_IPointer的空对象。并且将ClickObject脚本附加到对象上。

    步骤四：启动，并点击Panel_IPointer对象。在Console输出如下：

 

    方式二：Unity3D编辑器操作设置实现

    

步骤一：创建一个C#脚本。在脚本中添加一个public方法。

步骤二：创建一个命名为Empty的UI对象，用于接收和响应点击事件。创建一个名为Panel的UI对象，用于触发点击事件。

 

步骤三：Panel对象添加EventTrigger组件，" Add New" -> 选择" PointerClick"。将Empty对象拖拽到触发者位置。然后点击"No Function"选择我们写在Test脚本中的OnTestClick事件。

 

    步骤四：设置好这些之后。我们的事件触发就已经完成了。运行Unity3D。点击窗口中Panel对象。Console输出内容如下：

    方式三：程序动态设置实现

    我们在日常的开发中。可能需要动态的需要变更绑定的事件。那么我们如何才能使用C#代码控制绑定触发事件呢？

    下面我们就介绍代码控制。ScriptControl.cs脚本

using UnityEngine;using System.Collections;using UnityEngine.UI;public class BtnControl : MonoBehaviour {    // Use this for initialization    void Start ()    {        var button = transform.gameObject.GetComponent<Button>();        if (button != null)        {            button.onClick.RemoveAllListeners();            button.onClick.AddListener(TestClick);        }    }    public void TestClick()    {        Debug.Log("Test Click. This is Type 4");    }        // Update is called once per frame    void Update () {            }}