Game Events as ScriptableObjects

readme.md

Game Events as ScriptableObjects

Put GameEventInspector.cs in an Editor folder. After Unity's done compiling, pick a folder where you want to put your GameEvent asset. Right click in the folder view, click on Create/Game Events/GameEvent.

GameEvent.cs

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

namespace GameEvents {

    [CreateAssetMenu(menuName = "Game Events/GameEvent")]
    public class GameEvent : ScriptableObject {

        private readonly List<GameEventListener> eventListeners = new List<GameEventListener>();
        private Action callbacks = () => { };

        public void Invoke() {
            for (int i = eventListeners.Count - 1; i >= 0; i--) {
                eventListeners[i].OnEventRaised();
            }
            callbacks.Invoke();
        }

        public void RegisterListener(GameEventListener listener) {
            if (!eventListeners.Contains(listener)) {
                eventListeners.Add(listener);
            }
        }

        public void UnregisterListener(GameEventListener listener) {
            eventListeners.Remove(listener);
        }

        public void RegisterCallback(Action callback) {
            callbacks -= callback;
            callbacks += callback;
        }

        public void UnregisterCallback(Action callback) {
            callbacks -= callback;
        }
    }
}

GameEventInspector.cs

using UnityEditor;
using UnityEngine;

namespace GameEvents {

    [CustomEditor(typeof(GameEvent))]
    public class GameEventInspector : Editor {
        
        public override void OnInspectorGUI() {
            base.OnInspectorGUI();

            GUI.enabled = Application.isPlaying;

            if (GUILayout.Button("Invoke")) {
                (target as GameEvent)?.Invoke();
            }
        }
    }
}

GameEventListener.cs

using UnityEngine;
using UnityEngine.Events;

namespace GameEvents {

    public class GameEventListener : MonoBehaviour {
        
        [Tooltip("Event to register with.")]
        public GameEvent gameEvent;

        [Tooltip("Response to invoke when gameEvent is raised.")]
        public UnityEvent response;

        private void OnEnable() {
            gameEvent.RegisterListener(this);
        }

        private void OnDisable() {
            gameEvent.UnregisterListener(this);
        }

        public void OnEventRaised() {
            response.Invoke();
        }
    }
}