berry-dash-with-guns-custom/Assets/Scripts/HoldableButton.cs

using UnityEngine;
using UnityEngine.EventSystems;

public class HoldableButton : MonoBehaviour, IPointerDownHandler, IPointerUpHandler
{
    public bool isPressed;

    public void OnPointerDown(PointerEventData eventData)
    {
        isPressed = true;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        isPressed = false;
    }
}