Unity UGUI Button扩展

由于UGUI中的Button组件只能添加Click一种事件有一定的局限性，如果我要做当按钮被按下时并且手指不离开屏幕让按钮缩小如果只用Click事件当手指滑动到其他地方后就没办法恢复到按钮原来的大小了。还比如我没还要检测手指在按钮上滑动的距离这时Button组件明显也不满足需求。所以我就根据UGUI中Button组件的源码写了拥有按下、抬起、离开按钮、开始滑动、停止滑动、滑动等事件的组件代码如下：

using System;

using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;
using UnityEngine.Serialization;
using UnityEngine.UI;

[AddComponentMenu("UGUIExpend/UITouch", 30)]
public class UITouch : Selectable, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    [Serializable]
    public class TouchEvent : UnityEvent
    {
        public PointerEventData  eventData = default;
    }

    [SerializeField]
    private TouchEvent m_OnTouchDown = new TouchEvent();

    [SerializeField]
    private TouchEvent m_OnTouchUp = new TouchEvent();

    [SerializeField]
    private TouchEvent m_OnTouchExit = new TouchEvent();

    [SerializeField]
    private TouchEvent m_OnBeginSlide = new TouchEvent();

    [SerializeField]
    private TouchEvent m_OnSlide = new TouchEvent();

    [SerializeField]
    private TouchEvent m_OnEndSlide = new TouchEvent();

    protected UITouch(){}
    public TouchEvent OnTouchDown
    {
        get { return this.m_OnTouchDown; }
        set { m_OnTouchDown = value; }
    }

    public TouchEvent OnTouchUp
    {
        get { return this.m_OnTouchUp; }
        set { this.m_OnTouchUp = value; }
    }

    public TouchEvent OnTouchExit
    {
        get { return m_OnTouchExit; }
        set { m_OnTouchExit = value; }
    }

    public TouchEvent OnBeginSlider
    {
        get { return m_OnBeginSlide; }
        set { m_OnBeginSlide = value; }
    }

    public TouchEvent OnSlider
    {
        get { return m_OnSlide; }
        set { m_OnSlide = value; }
    }
    public TouchEvent OnEndSlider
    {
        get { return m_OnEndSlide; }
        set { m_OnEndSlide = value; }
    }

    private void touchDownOption(PointerEventData eventData)
    {
        if(!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnTouchDown",this);
        m_OnTouchDown.eventData = eventData;
        m_OnTouchDown.Invoke();
    }

    private void touchExitOption(PointerEventData eventData)
    {
        if (!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnTouchExit", this);
        m_OnTouchExit.eventData = eventData;
        m_OnTouchExit.Invoke();
    }

    private void touchUpOption(PointerEventData eventData)
    {
        if (!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnTouchUp", this);
        m_OnTouchUp.eventData = eventData;
        m_OnTouchUp.Invoke();
    }

    private void slideOption(PointerEventData eventData)
    {
        if (!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnSlider", this);
        m_OnSlide.eventData = eventData;
        m_OnSlide.Invoke();
    }
    private void beginSlideOption(PointerEventData eventData)
    {
        if (!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnSlider", this);
        m_OnBeginSlide.eventData = eventData;
        m_OnBeginSlide.Invoke();
    }
    private void endSlideOption(PointerEventData eventData)
    {
        if (!IsActive() || !IsInteractable())
        {
            return;
        }
        UISystemProfilerApi.AddMarker("UITouch.OnSlider", this);
        m_OnEndSlide.eventData = eventData;
        m_OnEndSlide.Invoke();
    }
    public override void OnPointerDown(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        touchDownOption(eventData);
    }
    public override void OnPointerUp(PointerEventData eventData)
    {
        if(eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        touchUpOption(eventData);
    }
    public override void OnPointerExit(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        touchExitOption(eventData);
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        beginSlideOption(eventData);
        //throw new NotImplementedException();
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        slideOption(eventData);
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        if (eventData.button != PointerEventData.InputButton.Left)
        {
            return;
        }
        endSlideOption(eventData);
    }
}