Ui image appear and disappear on trigger

Questions & Answers
1

I am new to unity and I would like to understand how to make to appear an image when I enter to the trigger, and that when I exit to the trigger the image disappears.
I tried to write this. Did I do something wrong? because this does not work. The image of the canvas always remains.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class SeeObjectWhenEnterInTrigger : MonoBehaviour
{
    [SerializeField] private Image customimage;

    void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Player"))
        {
            customimage.enabled = true;
        }
    }

    void OnTriggerExit(Collider other)
    {
        if (other.CompareTag("Player"))
        {
            customimage.enabled = false;
        }
    }
}
2

Looks fine. Standard questions:

  • Are you sure you’ve actually attached
    this to an object?

  • Are you sure the object this is
    attached to also has a Collider
    attached set to IsTrigger?

  • Are you sure you’ve assigned the
    image reference in the inspector and
    it’s not throwing errors when trying
    to change it’s Enabled status?

  • Are you sure the player object
    actually has its tag set to “Player”?

  • Are you sure the player object has a
    CharacterController or a rigidbody
    AND collider attached, to be able to
    activate triggers?

  • Are you sure that the layer this
    object is on, and the layer the
    Player object is on, are capable of
    colliding with one-another (check the
    Edit → Project Settings → Physics → Layer Collision Matrix)?

  • Are you sure that the GameObject the
    image is on isn’t disabled, or that’s
    the canvas parent isn’t disabled?

  • Are you sure that it isn’t actually
    working, but the image is out of
    range of the camera, or that it’s not
    visible to that camera specifically
    (on a layer not rendered by that
    camera)?

Lots and lots of things that this could be. Throw a Debug.Log check into the TriggerEnter/Exit functions to see if they’re firing, and then go through the possibilities I’ve listed one by one based on whether it isn’t getting that far (a problem with layers or colliders), or if it’s getting that far and not mattering (a problem with the canvas / image object).