Unity-Type-Based-Event-Manager

An Event Manager script for unity where you register events with Struct/Class types, then trigger them with instances of those Struct/Class types.

Initializing the EventManager.

To initialize the EventManager, you must place it on a single object (such as an empty Game Controller object) in the scene. This is so in each scene that relies on the EventManager it can reset the registered event listeners.

Defining an event

You can define an event as a struct, or a class, or any data type.

events.cs

public struct MoveEvent {
    public int distance;
}

Add Event Listener

Say we have a cube object that we want to move when an event is triggered. To register a listener for it, we'd do like so

Cube.cs

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

public class Cube : MonoBehaviour {

    void Start () {
        EventManager.AddEventListener<MoveEvent>((data) => {
            Move(data.distance);
        });
    }
    
    void Move(int distance) {
        var transform = this.GetComponent<Transform>();
        var position = transform.position;
        position.x += distance;
        transform.position = position;
    }
}

Remove Event Listener

You may also remove an event listener using the Event type, and a reference to the listener you used to attach it. So if you wish to remove an event programatically, do not use an anonymous callback function.

Cube.cs

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

public class Cube : MonoBehaviour {

    void Start () {
        EventManager.AddEventListener<MoveEvent>(DoMoveEvent);
        EventManager.RemoveEventListener<MoveEvent>(DoMoveEvent);
    }

    void DoMoveEvent(MoveEvent data) {
        var transform = this.GetComponent<Transform>();
        var position = transform.position;
        position.x += data.distance;
        transform.position = position;
    }
}

Trigger Event

And finally, to trigger the event, we just pass a new instance of the event type to the Trigger method.

GameController.cs

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

public class GameController : Singleton<GameController> {

    // Use this for initialization
    void Start () {
        
    }
    
    // Update is called once per frame
    void Update () {
        
        if (Input.GetKeyDown(KeyCode.Space)) {
            EventManager.TriggerEvent (new MoveEvent{distance=1});
        }
    }
}

Other Methods

GetListenersOfEvent<T>() => List<Delegate> -- Get a list of all listeners for an event. Returns a new empty list if a listener was never added to the event.

RemoveEvent<T>() => void -- Remove all listeners for an event, and remove the event itself from the event dictionary.

RemoveAllEvents() => void -- Remove all listeners for all events. Completely reset the event dictionary