从EventTriggerType枚举中可以看出UGUI支持的事件有哪些。

namespace UnityEngine.EventSystems
{
    /// <summary>
    /// 此类能够从指定的事件触发一个或多个远程函数
    /// 用法：使用碰撞器将其附加到对象上，或附加到您选择的GUI图形上。
    /// 注意：这样做将使该对象截获所有事件，并且不会从该对象中发生事件冒泡！
    /// </summary>

    public enum EventTriggerType
    {
        /// <summary>
        /// 拦截一个 IPointerEnterHandler.OnPointerEnter
        /// </summary>
        PointerEnter = 0,

        /// <summary>
        /// 拦截一个 IPointerExitHandler.OnPointerExit.
        /// </summary>
        PointerExit = 1,

        /// <summary>
        /// 拦截一个 IPointerDownHandler.OnPointerDown.
        /// </summary>
        PointerDown = 2,

        /// <summary>
        /// 拦截一个 IPointerUpHandler.OnPointerUp.
        /// </summary>
        PointerUp = 3,

        /// <summary>
        /// 拦截一个 IPointerClickHandler.OnPointerClick.
        /// </summary>
        PointerClick = 4,

        /// <summary>
        /// 拦截一个 IDragHandler.OnDrag.
        /// </summary>
        Drag = 5,

        /// <summary>
        /// 拦截一个 IDropHandler.OnDrop.
        /// </summary>
        Drop = 6,

        /// <summary>
        /// 拦截一个 IScrollHandler.OnScroll.
        /// </summary>
        Scroll = 7,

        /// <summary>
        /// 拦截一个 IUpdateSelectedHandler.OnUpdateSelected.
        /// </summary>
        UpdateSelected = 8,

        /// <summary>
        /// 拦截一个 ISelectHandler.OnSelect.
        /// </summary>
        Select = 9,

        /// <summary>
        /// 拦截一个 IDeselectHandler.OnDeselect.
        /// </summary>
        Deselect = 10,

        /// <summary>
        /// 拦截一个 IMoveHandler.OnMove.
        /// </summary>
        Move = 11,

        /// <summary>
        /// 拦截 IInitializePotentialDrag.InitializePotentialDrag.
        /// </summary>
        InitializePotentialDrag = 12,

        /// <summary>
        /// 拦截 IBeginDragHandler.OnBeginDrag.
        /// </summary>
        BeginDrag = 13,

        /// <summary>
        /// 拦截 IEndDragHandler.OnEndDrag.
        /// </summary>
        EndDrag = 14,

        /// <summary>
        /// 拦截 ISubmitHandler.Submit.
        /// </summary>
        Submit = 15,

        /// <summary>
        /// 拦截 ICancelHandler.OnCancel.
        /// </summary>
        Cancel = 16
    }
}