Can't subscribe listeners to an Event.

Unity Engine
,
1

I have created an event that will run when an interactable object enters the radius of the player, but when attempting to subscribe other scripts to the events I get this error: NullReferenceException: Object reference not set to an instance of an object.

I thought at first it was a was a script execution order error and the other scripts were calling on the singleton instance before it was set, but when I changed the order to be sure the instance was first establish the error persisted. I found a thread with a similar problem here: Why can I not subscribe to an event of a singleton?
but they gave up on trying to find a solution.

This is my event handler script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using System;
//System is require to used GameEvents

public class GameEvents : MonoBehaviour
{
    /*
    This is the Custom Event System.
    This Script will contain ways to notify other scripts when an event occours.
    Events like playerdeath, when a player can interact, or the end of a round.
    All objects that react to events will need access to this script.
    There can only be one instance of this object
    This helps reduce the amount of dependancies
    -S
    */

    //This is the refference to the script.
    public static GameEvents current;

    private void awake()
    {  
        current = this;
      
    }

    //This is the Event to allow the player to Interact
    public event Action onInteractionRadiusEnter;
    //This is the Fuction of that Event that notifies the other scripts the radius has been entered
    public void interactionRadiusEnter()
    {  
        if(onInteractionRadiusEnter != null)
        {
            onInteractionRadiusEnter();
            Debug.Log("interaction radius entered");
        }
    }

    public event Action onInteractionRadiusExit;

    public void interactionRadiusExit()
    {
        if(onInteractionRadiusExit != null)
        {
           onInteractionRadiusExit();
        }
    }
}

and this is the script I am trying to subscribe to the event:

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

public class PlayerInteraction : MonoBehaviour
{
    private bool playerCanInteractWithObjects = false;
    private GameObject objectToInteractWith;
    private Interactable objectInteraction;

    private void Start()
    {
      GameEvents.current.onInteractionRadiusEnter += playerCanInteract;
      GameEvents.current.onInteractionRadiusExit += playerCannotInteract;
    }

    //This Triggers the enter event;



    public void OnTriggerEnter2D(Collider2D other)
    {
        if (other.gameObject.CompareTag("Interactable"))
        {
            objectToInteractWith = other.gameObject;
            GameEvents.current.interactionRadiusEnter();
            Debug.Log("inteaction raduis entered");
        }

    }

    //This triggers the exit Event
    public void OnTriggerExit2D(Collider2D other)
    {
        if (other.gameObject.CompareTag("Interactable"))
        {
            objectToInteractWith = null;
            GameEvents.current.interactionRadiusExit();
        }

    }

its worth noting that this error isn’t isolated to this script. I’ve create other scripts just to see if they can subscribe and they cannot. I am completely out of ideas on this one.

2

The singleton instance is null because of this:

    private void awake()
    {
        current = this;
   
    }

Awake should be spelled with a capital “A”.

On a somewhat unrelated note, you can shorten your event invocations from this…

if(someEvent != null)
{
   someEvent();
}

…To this:

someEvent?.Invoke();
3

god, thats is embarrassing. Thank you so much mate. I spent 2 hours trying to figure this out

4

Can you please describe how you fixed this? I think I’m having the same problem and I’m too much of a noob to solve it.

5

Hello

He write Awake instead of awake.

Christoph