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Using Pointer-Related Events in Unity UI

How to use pointer-related interfaces and events in Unity

Unity allows the implementation of up to 5 interfaces to handle pointer-related events while working with UI.

Namely, the interfaces are:

• IPointerClickHandler
• IPointerDownHandler
• IPointerEnterHandler
• IPointerExitHandler
• IPointerUpHandler

which you can explore better in the Official Scripting API manual. Each interface exposes a method, respectively:

OnPointerClick(PointerEventData pointerEventData)

OnPointerDown(PointerEventData pointerEventData)

OnPointerEnter(PointerEventData pointerEventData)

OnPointerExit(PointerEventData pointerEventData)

OnPointerUp(PointerEventData pointerEventData)

Similar to the collider ones, those methods are triggered when the user interacts with a UI element using the mouse pointer. Of course, the element should have a script attached, implementing the interface. An example of implementation would be:

OnPointerenter(PointerEventData pointerEventData){
    //stuff to do when the pointer hovers above THIS UI element
}