EventSystem に乗っからないで自前でイベントを管理するヤツ

UGUITouchFinger.cs

using System.Linq;
using UnityEngine;
using System.Collections.Generic;
using UnityEngine.EventSystems;
using UnityEngine.UI;

public class UGUITouchFinger : MonoBehaviour
{
    public enum State
    {
        Hover, Touch
    }

    public Camera eventCamera 
    {
        get { return Camera.main; }
    }

    public EventSystem eventSystem
    {
        get { return EventSystem.current; }
    }

    Canvas[] canvases
    {
        get { return FindObjectsOfType<Canvas>(); }
    }

    private Dictionary<Graphic, State> graphicsStates_ = new Dictionary<Graphic, State>();


    void Update()
    {
        var currentGraphicStates = GetCurrentGraphicStates();
        DispatchEvents(currentGraphicStates);
        graphicsStates_ = currentGraphicStates;
    }


    Dictionary<Graphic, State> GetCurrentGraphicStates()
    {
        var fingerScreenPos = Camera.main.WorldToScreenPoint(transform.position);

        var currentTouchingGraphicsStates = new Dictionary<Graphic, State>();
	    foreach (var canvas in canvases.Where(c => c.enabled)) {
	        var graphics = GraphicRegistry.GetGraphicsForCanvas(canvas);
	        foreach (var graphic in graphics.Where(g => g.depth != -1)) {
	            // 範囲に収まっていないものを除く
	            if (!RectTransformUtility.RectangleContainsScreenPoint(graphic.rectTransform, fingerScreenPos, eventCamera) ||
	                !graphic.Raycast(fingerScreenPos, eventCamera)) {
	                continue;
	            }

	            var distance = Vector3.Dot(graphic.transform.forward, graphic.transform.position - transform.position);
	            currentTouchingGraphicsStates.Add(graphic, (distance < 0f ? State.Touch : State.Hover));
	        }
	    }

        return currentTouchingGraphicsStates;
    }


    void DispatchEvents(Dictionary<Graphic, State> currentGraphicStates)
    {
        foreach (var keyValue in currentGraphicStates) {
            var graphic = keyValue.Key;
            var state = keyValue.Value;

            if (graphicsStates_.ContainsKey(graphic)) {
                var preState = graphicsStates_[graphic];
                if (preState == State.Hover && state == State.Touch) {
                    ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerDownHandler);
                    Debug.Log("Touch Start"); 
                } else if (preState == State.Touch && state == State.Hover) {
                    ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerUpHandler);
                    ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerClickHandler);
                    Debug.Log("Touch End"); 
                } else {
                    // Debug.Log("-"); 
                }
                graphicsStates_.Remove(graphic);
            } else {
                ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerEnterHandler);
                if (state == State.Touch) {
                    ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerDownHandler);
                    Debug.Log("Touch Start (Direct)"); 
                }
            }
        }

        foreach (var keyValue in graphicsStates_) {
            var graphic = keyValue.Key;
            var state   = keyValue.Value;

            if (state == State.Touch) {
                ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerUpHandler);
                ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerClickHandler);
                Debug.Log("Touch End (Direct)"); 
            }
            ExecuteEvents.ExecuteHierarchy(graphic.gameObject, new PointerEventData(eventSystem), ExecuteEvents.pointerExitHandler);
        }

    }
}

これのやつです： https://www.youtube.com/watch?v=NY4oGnBfRO0