Unity3D: How to detect when a button is being held down and released [duplicate] - user-interface

Question

This question already has answers here:
How to detect click/touch events on UI and GameObjects
(4 answers)
Closed 3 years ago.
I have a UI button. I want to show a text when the user is pressing the button and hide the text when the user releases the button.
How can I do this?

Answer 1

this anwser is basically fine but there is a huge drawback: You can't have additional fields in the Inspector since Button already has a built-in EditorScript which overwrites the default Inspector - You would need to extend this via a custom Inspector every time.
I would instead implement it as completely additional component implementing IPointerDownHandler and IPointerUpHandler (and maybe also IPointerExitHandler to reset also when exiting the button while holding the mouse/pointer still pressed).
For the doing something while the button stays pressed I'ld use a Coroutine.
In general I'ld use UnityEvents:
[RequireComponent(typeof(Button))]
public class PointerDownUpHandler : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerEnterHandler, IPointerExitHandler
{
public UnityEvent onPointerDown;
public UnityEvent onPointerUp;
// gets invoked every frame while pointer is down
public UnityEvent whilePointerPressed;
private Button _button;
private void Awake()
{
_button = GetComponent<Button>();
}
private IEnumerator WhilePressed()
{
// this looks strange but is okey in a Coroutine
// as long as you yield somewhere
while(true)
{
whilePointerPressed?.Invoke();
yield return null;
}
}
public void OnPointerDown(PointerEventData eventData)
{
// ignore if button not interactable
if(!_button.interactable) return;
// just to be sure kill all current routines
// (although there should be none)
StopAllCoroutines();
StartCoroutine(WhilePressed);
onPointerDown?.Invoke();
}
public void OnPointerUp(PointerEventData eventData)
{
StopAllCoroutines();
onPointerUp?.Invoke();
}
public void OnPointerExit(PointerEventData eventData)
{
StopAllCoroutines();
onPointerUp?.Invoke();
}
// Afaik needed so Pointer exit works .. doing nothing further
public void OnPointerEnter(PointerEventData eventData) { }
}
Than you can reference any callback in onPointerDown, onPointerUp and whilePointerPressed just the way you would do it with the onClick event of the Button.

Answer 2

You have to create your own custom button by extending Button class and override method OnPoiterDown and OnPointerUp.
Attach MyButton component instead of Button to your gameobject
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
public class MyButton : Button
{
public override void OnPointerDown(PointerEventData eventData)
{
base.OnPointerDown(eventData);
Debug.Log("Down");
//show text
}
public override void OnPointerUp(PointerEventData eventData)
{
base.OnPointerUp(eventData);
Debug.Log("Up");
//hide text
}
}