NGUI研究院之三种方式监听NGUI的事件方法（七）

NGUI事件的种类很多，比如点击、双击、拖动、滑动等等，他们处理事件的原理几乎万全一样，本文只用按钮来举例。

1.直接监听事件

把下面脚本直接绑定在按钮上，当按钮点击时就可以监听到，这种方法不太好很不灵活。

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void OnClick()

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{

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    Debug.Log("Button is Click!!!");

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}

2.使用SendMessage

选择按钮后，在Unity导航菜单栏中选择Component->Interaction->Button Message 组件。

Target：接收按钮消息的游戏对象。

Function Name：接收按钮消息的方法，拥有这个方法的脚本必须绑定在上面Target对象身上。

Trigger：触发的事件，OnClick显然是一次点击。

Include Children ：是否让该对象的所有子对象也发送这个点击事件。

到UIButtonMessage.cs这个脚本中看看，其实很简单就是调用Unity自身的SendMessage而已。

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void Send ()

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{

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    if (string.IsNullOrEmpty(functionName)) return;

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    if (target == null) target = gameObject;

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    if (includeChildren)

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    {

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        Transform[] transforms = target.GetComponentsInChildren<Transform>();

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        for (int i = 0, imax = transforms.Length; i < imax; ++i)

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        {

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            Transform t = transforms[i];

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            t.gameObject.SendMessage(functionName, gameObject, SendMessageOptions.DontRequireReceiver);

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        }

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    }

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    else

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    {

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        target.SendMessage(functionName, gameObject, SendMessageOptions.DontRequireReceiver);

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    }

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}

3.使用UIListener

这个也是推荐大家使用的一种方法，选择按钮后在Unity导航菜单栏中选择Component->NGUI->Internal ->Event Listener 。挂在按钮上就可以，它没有任何参数。。

在任何一个脚本或者类中即可得到按钮的点击事件、把如下代码放在任意类中或者脚本中。

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void Awake () 

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{   

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            //获取需要监听的按钮对象

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    GameObject button = GameObject.Find("UI Root (2D)/Camera/Anchor/Panel/LoadUI/MainCommon/Button");

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            //设置这个按钮的监听，指向本类的ButtonClick方法中。

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    UIEventListener.Get(button).onClick = ButtonClick;

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}

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    //计算按钮的点击事件

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void ButtonClick(GameObject button)

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{

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    Debug.Log("GameObject " + button.name);

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}

怎么样是不是很灵活？再看看它的源码，使用的C#的代理，将UI的场景事件通过代理传递出去了。

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public class UIEventListener : MonoBehaviour

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{

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    public delegate void VoidDelegate (GameObject go);

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    public delegate void BoolDelegate (GameObject go, bool state);

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    public delegate void FloatDelegate (GameObject go, float delta);

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    public delegate void VectorDelegate (GameObject go, Vector2 delta);

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    public delegate void StringDelegate (GameObject go, string text);

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    public delegate void ObjectDelegate (GameObject go, GameObject draggedObject);

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    public delegate void KeyCodeDelegate (GameObject go, KeyCode key);

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    public object parameter;

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    public VoidDelegate onSubmit;

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    public VoidDelegate onClick;

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    public VoidDelegate onDoubleClick;

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    public BoolDelegate onHover;

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    public BoolDelegate onPress;

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    public BoolDelegate onSelect;

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    public FloatDelegate onScroll;

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    public VectorDelegate onDrag;

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    public ObjectDelegate onDrop;

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    public StringDelegate onInput;

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    public KeyCodeDelegate onKey;

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    void OnSubmit ()                { if (onSubmit != null) onSubmit(gameObject); }

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

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    void OnDoubleClick ()           { if (onDoubleClick != null) onDoubleClick(gameObject); }

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    void OnHover (bool isOver)      { if (onHover != null) onHover(gameObject, isOver); }

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    void OnPress (bool isPressed)   { if (onPress != null) onPress(gameObject, isPressed); }

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    void OnSelect (bool selected)   { if (onSelect != null) onSelect(gameObject, selected); }

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    void OnScroll (float delta)     { if (onScroll != null) onScroll(gameObject, delta); }

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    void OnDrag (Vector2 delta)     { if (onDrag != null) onDrag(gameObject, delta); }

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    void OnDrop (GameObject go)     { if (onDrop != null) onDrop(gameObject, go); }

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    void OnInput (string text)      { if (onInput != null) onInput(gameObject, text); }

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    void OnKey (KeyCode key)        { if (onKey != null) onKey(gameObject, key); }

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    /// <summary>

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    /// Get or add an event listener to the specified game object.

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    /// </summary>

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    static public UIEventListener Get (GameObject go)

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    {

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        UIEventListener listener = go.GetComponent<UIEventListener>();

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        if (listener == null) listener = go.AddComponent<UIEventListener>();

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        return listener;

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    }

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}