Unity绑定型输入事件响应机制

• 前言
• 一、继承型
• 二、绑定型
• 总结

输入事件的相应机制，一般有两种：
1.继承型
2.绑定型

继承型是指事件先响应到基类，再由基类反馈到父类，由父类做处理，这样UI既可以得到对事件的响应，也可以自行修改自己需要的逻辑。

绑定型是指在对事件响应之前，为UI元素绑定一个事件响应的组件。例如：编写一个绑定型事件类UIEvent，当某个UI元素需要输入事件的回调时，对这个物体绑定一个UIEvent，并且对UIEvent里需要的相关响应事件进行赋值或注册操作函数。
代码如下（示例）：

public class UIEvent:EventTrigger
{
    protected const float CLICK_INTERVAL_TIME = 0.2f;
    protected const float CLICK_INTERVAL_POS = 2;
    public delegate void PointerEventDelegate(PointerEventData eventData,UIEvent ev);
    public delegate void BaseEventDelegate(BaseEventData eventData,UIEvent ev);
    public delegate void AxisEventDelegate(AxisEventData eventData,UIEvent ev);
    public Dictionary mArgs = new Dictionary();

    public BaseEventDelegate onSelect = null;
    public BaseEventDelegate onDeselect = null;
    public BaseEventDelegate onUpdateSelect = null;
    public BaseEventDelegate onCancel = null;
    public BaseEventDelegate onSubmit = null;

    public PointerEventDelegate onBeginDrag = null;
    public PointerEventDelegate onDrag = null;
    public PointerEventDelegate onEndDrag = null;
    public PointerEventDelegate onDrop = null;
    public PointerEventDelegate onClick = null;
    public PointerEventDelegate onDown = null;
    public PointerEventDelegate onEnter = null;
    public PointerEventDelegate onExit = null;
    public PointerEventDelegate onUp = null;
    public PointerEventDelegate onScroll = null;
    public PointerEventDelegate onInitializePotentialDrag = null;

    public AxisEventDelegate onMove = null;

    private static PointerEventData mPointData = null;

    ///设置参数
    public void SetData(string key,object val)
    {
        mArgs[key] = val;
    }

    //获取参数
    public T GetData(string key)
    {
        if (mArgs.ContainsKey(key))
        {
            return (T)mArgs[key];
        }
        return default(T);
    }

    public static UIEvent Get(GameObject go)
    {
        UIEvent listener = go.GetComponent();
        if (listener == null)
        {
            listener = go.AddComponent();
        }
        return listener;
    }
    public override void OnPointerEnter(PointerEventData eventData)
    {
        base.OnPointerEnter(eventData);
        onEnter?.Invoke(eventData,this);
    }

    public override void OnPointerExit(PointerEventData eventData)
    {
        base.OnPointerExit(eventData);
        onExit?.Invoke(eventData, this);
    }

    public override void OnDrag(PointerEventData eventData)
    {
        base.OnDrag(eventData);
        onDrag?.Invoke(eventData, this);
    }

    public override void OnDrop(PointerEventData eventData)
    {
        base.OnDrop(eventData);
        onDrop?.Invoke(eventData,this);
    }

    public override void OnPointerDown(PointerEventData eventData)
    {
        base.OnPointerDown(eventData);
        onDown?.Invoke(eventData,this);
    }

    public override void OnPointerUp(PointerEventData eventData)
    {
        base.OnPointerUp(eventData);
        onUp?.Invoke(eventData,this);
    }

    public override void OnPointerClick(PointerEventData eventData)
    {
        base.OnPointerClick(eventData);
        onClick?.Invoke(eventData,this);
    }

    public override void OnSelect(BaseEventData eventData)
    {
        base.OnSelect(eventData);
        onSelect?.Invoke(eventData,this);
    }

    public override void OnDeselect(BaseEventData eventData)
    {
        base.OnDeselect(eventData);
        onDeselect?.Invoke(eventData,this);
    }

    public override void OnScroll(PointerEventData eventData)
    {
        base.OnScroll(eventData);
        onScroll?.Invoke(eventData,this);
    }

    public override void OnMove(AxisEventData eventData)
    {
        base.OnMove(eventData);
        onMove?.Invoke(eventData,this);
    }

    public override void OnUpdateSelected(BaseEventData eventData)
    {
        base.OnUpdateSelected(eventData);
        onUpdateSelect?.Invoke(eventData,this);
    }

    public override void OnInitializePotentialDrag(PointerEventData eventData)
    {
        base.OnInitializePotentialDrag(eventData);
        onInitializePotentialDrag?.Invoke(eventData,this);
    }

    public override void OnBeginDrag(PointerEventData eventData)
    {
        base.OnBeginDrag(eventData);
        onBeginDrag?.Invoke(eventData,this);
    }

    public override void OnEndDrag(PointerEventData eventData)
    {
        base.OnEndDrag(eventData);
        onEndDrag?.Invoke(eventData,this);
    }

    public override void OnSubmit(BaseEventData eventData)
    {
        base.OnSubmit(eventData);
        onSubmit?.Invoke(eventData,this);
    }

    public override void OnCancel(BaseEventData eventData)
    {
        base.OnCancel(eventData);
        onCancel?.Invoke(eventData,this);
    }
}

继承型和绑定型有一个共同的特点，都需要与UI元素相关联，其区别是继承型融入在了各种组件内，而绑定型是以独立的组件形式体现出来的。