Detect IPointerEnterHander On Nested UI Element

Question

I have a card which has some icons on it. The card has an IPointerEnterHandler on it and it works fine and is called when the mouse enters the object. The card has a hidden button that covers the surface.

The problem is, there are some nested GameObjects that I want to detect IPointerEnterHandler events on. I have IPointerEnterHandler listeners on those objects, but they dont fire.

If I remove them from the card, they will fire when hovered. However, while on the card, they will not fire.

Here is a visual example, as well as the heirachy and the arrows correspond to the icons and their place in the hierarchy:

I tried using the EventSystem in an Update call on but the currentSelectedObject is always the Card (or rather the cards button which covers it).

private void Update()
{
    Debug.Log(EventSystem.current.currentSelectedGameObject);

    if (EventSystem.current.currentSelectedGameObject == gameObject)
    {
        Debug.Log(1);
    }
}

Do you know how I can detect mouse over events on these nested objects (which have a UI element above them that is hogging the event)?. I'd like to avoid RayCasting if possible.

Temp Solution:

I've resorted to using a raycast for the time being. I put a collider on the small icon and I check if its hit while the mouse is over the card:

private void Update()
{
    if (!_mouseIsOver)
    {
        HideActionOrPerk();
        return;
    }

    // If it's already showing a card then dont bother checking to show again
    if (_shownCardClone != null) return;

    Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
    RaycastHit[] hits = Physics.RaycastAll(ray, 100.0f);
    Debug.Log(hits);
    foreach(RaycastHit hit in hits)
    {
        S_ActionOrPerkIcon icon = hit.transform.GetComponent<S_ActionOrPerkIcon>();
        if (icon != null)
        {
            ShowActionOrPerk(icon.tooltipCardGO);
        }
    }
}

I would have preferred the icon to handle this logic but this works for the time being. Better suggestions welcome.

Update The component view is as follows:

[https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem.IsPointerOverGameObject.html](https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem.IsPointerOverGameObject.html), there's a dup around here somewhere. — Draco18s no longer trusts SE, Sep 27 '18 at 01:09
If this is a dup I will delete. I did not find a similar when making question. — Aggressor, Sep 27 '18 at 01:15
With regards to your doc reference, I believe that just just tells me if its over a GameObject, not if its over the specific element. — Aggressor, Sep 27 '18 at 01:20
[This, then most likely](https://docs.unity3d.com/ScriptReference/EventSystems.EventSystem-currentSelectedGameObject.html). — Draco18s no longer trusts SE, Sep 27 '18 at 01:26
As you can see in the question, I discussed that literally didn't work — Aggressor, Sep 27 '18 at 01:27
Can you select the one of the icons then post screenshot of it's Inspector tab? I need to see what components are attached to it. — Programmer, Oct 01 '18 at 14:44
I had this precise issue, but the problem was my fault: I had apparently unchecked "Raycast Target" on the items that weren't working. Maybe that will help someone someday. — Harold, Feb 03 '22 at 23:26

Dave · Answer 1 · 2018-09-27T13:40:00.513

1

Make the hidden button that covers the surface as a child of actionsTray object. Move it to top of the childs list in hierarchy. This way you can place other elements above the "hidden button" and allow them to trigger their IPointerEnterHandler method.

Edit: You can also use RectTransformUtility.RectangleContainsScreenPoint() if you can't change the order of objects.

edited Sep 27 '18 at 13:40

answered Sep 27 '18 at 11:54

Dave

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There are reasons I cant do that. There are other card interactions that require the button to always be topmost – Aggressor Sep 27 '18 at 12:07
OK, I don't know how your code works, maybe there are other ways. What about using sprite.rect.Contains(pointer.pos)? – Dave Sep 27 '18 at 12:24
Ah interesting let me try that – Aggressor Sep 27 '18 at 12:27
I put that in the update function but out of the box its not working. Will investigate – Aggressor Sep 27 '18 at 12:32
Instead use RectTransformUtility.RectangleContainsScreenPoint() – Dave Sep 27 '18 at 13:30

Detect IPointerEnterHander On Nested UI Element

1 Answers1