Unity UGUI Button擴展

由於UGUI中的Button組件只能添加Click一種事件有一定的局限性，如果我要做當按鈕被按下時並且手指不離開屏幕讓按鈕縮小如果只用Click事件當手指滑動到其他地方后就沒辦法恢復到按鈕原來的大小了。還比如我沒還要檢測手指在按鈕上滑動的距離這時Button組件明顯也不滿足需求。所以我就根據UGUI中Button組件的源碼寫了擁有按下、抬起、離開按鈕、開始滑動、停止滑動、滑動等事件的組件代碼如下：

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);
    }
}