EventTrigger

Description

Receives events from the EventSystem and calls registered functions for each event.

The EventTrigger can be used to specify functions you wish to be called for each EventSystem event. You can assign multiple functions to a single event and whenever the EventTrigger receives that event it will call those functions in the order they were provided.

NOTE: Attaching this component to a GameObject will make that object intercept ALL events, and no events will propagate to parent objects.

There are two ways to intercept events: You could extend EventTrigger, and override the functions for the events you are interested in intercepting; as shown in this example:

using UnityEngine;
using UnityEngine.EventSystems;

public class EventTriggerExample : EventTrigger
{
    public override void OnBeginDrag(PointerEventData data)
    {
        Debug.Log("OnBeginDrag called.");
    }

    public override void OnCancel(BaseEventData data)
    {
        Debug.Log("OnCancel called.");
    }

    public override void OnDeselect(BaseEventData data)
    {
        Debug.Log("OnDeselect called.");
    }

    public override void OnDrag(PointerEventData data)
    {
        Debug.Log("OnDrag called.");
    }

    public override void OnDrop(PointerEventData data)
    {
        Debug.Log("OnDrop called.");
    }

    public override void OnEndDrag(PointerEventData data)
    {
        Debug.Log("OnEndDrag called.");
    }

    public override void OnInitializePotentialDrag(PointerEventData data)
    {
        Debug.Log("OnInitializePotentialDrag called.");
    }

    public override void OnMove(AxisEventData data)
    {
        Debug.Log("OnMove called.");
    }

    public override void OnPointerClick(PointerEventData data)
    {
        Debug.Log("OnPointerClick called.");
    }

    public override void OnPointerDown(PointerEventData data)
    {
        Debug.Log("OnPointerDown called.");
    }

    public override void OnPointerEnter(PointerEventData data)
    {
        Debug.Log("OnPointerEnter called.");
    }

    public override void OnPointerExit(PointerEventData data)
    {
        Debug.Log("OnPointerExit called.");
    }

    public override void OnPointerUp(PointerEventData data)
    {
        Debug.Log("OnPointerUp called.");
    }

    public override void OnScroll(PointerEventData data)
    {
        Debug.Log("OnScroll called.");
    }

    public override void OnSelect(BaseEventData data)
    {
        Debug.Log("OnSelect called.");
    }

    public override void OnSubmit(BaseEventData data)
    {
        Debug.Log("OnSubmit called.");
    }

    public override void OnUpdateSelected(BaseEventData data)
    {
        Debug.Log("OnUpdateSelected called.");
    }
}

...or you can specify individual delegates:

using UnityEngine;
using UnityEngine.EventSystems;


public class EventTriggerDelegateExample : MonoBehaviour
{
    void Start()
    {
        EventTrigger trigger = GetComponent<EventTrigger>();
        EventTrigger.Entry entry = new EventTrigger.Entry();
        entry.eventID = EventTriggerType.PointerDown;
        entry.callback.AddListener((data) => { OnPointerDownDelegate((PointerEventData)data); });
        trigger.triggers.Add(entry);
    }

    public void OnPointerDownDelegate(PointerEventData data)
    {
        Debug.Log("OnPointerDownDelegate called.");
    }
}

Properties

Public Methods

Inherited Members