Unity uGUI 长按事件

在Unity 4.6新增的uGUI中，可以方便地对控件，通过添加EventTrigger脚本来进行添加事件。但是里面并没有包括长按事件，需要自己来实现长按事件。

长按事件

以下是一种实现方式，来自《Handling long press events in uGUI (Unity 4.6)》

using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;

public class LongPressEventTrigger : UIBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler
{
    [Tooltip("How long must pointer be down on this object to trigger a long press")]
    public float durationThreshold = 1.0f;

    public UnityEvent onLongPress = new UnityEvent();

    private bool isPointerDown = false;
    private bool longPressTriggered = false;
    private float timePressStarted;

    private void Update()
    {
        if (isPointerDown && !longPressTriggered)
        {
            if (Time.time - timePressStarted > durationThreshold)
            {
                longPressTriggered = true;
                onLongPress.Invoke();
            }
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        timePressStarted = Time.time;
        isPointerDown = true;
        longPressTriggered = false;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        isPointerDown = false;
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        isPointerDown = false;
    }
}

长按或点击事件

当存在长按事件，又想存在点击事件时，那么就需要判断是否已经执行了长按事件，已经执行了就不能再执行点击事件了，代码如下：

using UnityEngine;
using UnityEngine.Events;
using UnityEngine.EventSystems;

public class LongPressOrClickEventTrigger : UIBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler, IPointerClickHandler
{
    [Tooltip("How long must pointer be down on this object to trigger a long press")]
    public float durationThreshold = 1.0f;

    public UnityEvent onLongPress = new UnityEvent();
    public UnityEvent onClick = new UnityEvent();

    private bool isPointerDown = false;
    private bool longPressTriggered = false;
    private float timePressStarted;

    private void Update()
    {
        if (isPointerDown && !longPressTriggered)
        {
            if (Time.time - timePressStarted > durationThreshold)
            {
                longPressTriggered = true;
                onLongPress.Invoke();
            }
        }
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        timePressStarted = Time.time;
        isPointerDown = true;
        longPressTriggered = false;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        isPointerDown = false;
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        isPointerDown = false;
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        if (!longPressTriggered)
        {
            onClick.Invoke();
        }
    }
}