OnHover & OnUnhover doesn't work as I intended

[wm-kim]

I am writing to discuss a specific behavior observed in Unity's UI event system related to the Hover and Unhover events.

Currently, the Hover and Unhover events work well in environments that utilize a mouse input. However, in touch-input environments like mobile, these events are not functioning as anticipated. Presently, they are triggered when a touch finger is lifted from the screen. However, it would seem more natural for these events to be called when the touch finger, while being pressed, enters a UI

With Unity UI's event system, using IPointerEnterHandler and IPointerExitHandler, the event is called when the pointer enters a UI element from an already pressed state outside it. If the Hover and Unhover events are designed intentionally not to work in this situation, I would like to kindly request a new event to be created to cater to the scenario described above (when the touch is pressed, and the pointer enters a UI block).

This modification will provide more intuitive interactions for users on touch-enabled devices and align the functionality of the system with the expectations of developers like myself.

I greatly appreciate your attention to this matter, and I look forward to hearing your thoughts on this request.

[adgray1]

What you're describing does sound like the intended/expected behavior of hover/unhover from the implementation perspective. Hover/Unhover are intended to only map to pointer enter/exit events, respectively, when the pointer is up - though we likely could be more explicit about the up aspect in our documentation. However, in order to ensure consistent visual state transitions across desktop/mobile/etc., the Interaction system will preempt a Press event with a Hover event as well as follow a Release event with a corresponding Unhover event in scenarios where the pointer positions are only reported while in a down state (e.g. touch screens) - which it sounds like is what you're observing.

None of the existing gesture events are expected (again, speaking from the current intended feature/implementation standpoint) to fire on pointer enter or on pointer exit while the pointer remains down.

All that said, I'm happy to recategorize this as a "Feature Request", since the ask certainly sounds like something Nova could support in the future with some new events!

In the meantime, however, if you're actively looking to unblock yourself, one option available to you today would be leveraging the more raw Interaction.Raycast method and firing gesture events based on any manually tracked input state more suited to your project! This will allow you to bypass the Interaction.Point gesture event behavior described above.

One ask on our end for future reference, just so we better understand the use case when we get to implementing the new functionality, perhaps you could elaborate on what you're currently trying to accomplish as well as other scenarios you see these events being useful in place of the existing gesture events? We'd really appreciate the additional insight!

[wm-kim]

Thank you for the response and the suggested solution. What I aim to implement is a system for previewing cards in a card game for a better user experience. In this system, while keeping the touch pressed, the player can move the touch over a card in their hand to preview it. Here is a simple gif for better understanding of my case.

Apart from this specific case, these events could also be useful in general scenarios on a touch screen, where the user wants to press, drag, and then drop into a designated UI area. When the dragging item enters or exits a specific area, the visual feedback can change accordingly. Although it's possible to implement this using raycasting as you suggested, I believe using events may allow for quicker and easier implementation of these feature. 😄