notification-center

A lightweight publish/subscribe (observer) message bus for Unity. Broadcast a notification from anywhere and let any number of receivers handle it, without direct references between them.

No dependencies, no MonoBehaviour, no scene object required
Observers are held by WeakReference, so a destroyed receiver never keeps the bus alive
Optional object pooling for Notification instances (NOTIFICATION_USE_POOL)

Requirements

Unity 2019.3 or later (required for installing packages via git URL)

Installation

Install via git URL

Edit Packages/manifest.json in your Unity project and add this repository as a dependency:

{
  "dependencies": {
    "com.ez.notification-center": "https://github.com/ez8801/notification-center.git"
  }
}

Or in the Unity Editor: Window > Package Manager > + > Add package from git URL... and paste:

https://github.com/ez8801/notification-center.git

Getting Started

All types live in the Foundation.Notifications namespace.

1. Declare notification names

A NotificationName is implicitly convertible to and from string. Collecting the names in one place avoids typos.

using Foundation.Notifications;

namespace R
{
    public class Id
    {
        public static readonly NotificationName OnHpChanged = nameof(OnHpChanged);
        public static readonly NotificationName OnMpChanged = nameof(OnMpChanged);
    }
}

2. Receive notifications

Implement INotificationReceiver and register the receiver with the notification center.

using UnityEngine;
using UnityEngine.UI;
using Foundation.Notifications;

public class HpBar : MonoBehaviour, INotificationReceiver
{
    [SerializeField]
    private Slider _slider;

    private void Awake()
    {
        // Start receiving OnHpChanged notifications.
        NotificationCenter.Instance.AddObserver(this, R.Id.OnHpChanged);
    }

    public void HandleNotification(Notification notification)
    {
        if (notification.Name == R.Id.OnHpChanged)
        {
            _slider.value = notification.IntExtra / 100f;
        }
    }

    private void OnDestroy()
    {
        NotificationCenter.Instance.RemoveObserver(this, R.Id.OnHpChanged);
    }
}

3. Post notifications

using Foundation.Notifications;

public class Player : MonoBehaviour
{
    public int Hp
    {
        get => _hp;
        set
        {
            _hp = value;

            // Post a notification with a payload.
            NotificationCenter.Post(R.Id.OnHpChanged, _hp);
        }
    }
    private int _hp;

    private void Pause()
    {
        // Post with no payload.
        NotificationCenter.Post("OnPaused");

        // Or build the notification yourself.
        Notification notification = Notification.Create("OnPaused", true);
        NotificationCenter.Post(notification);
    }
}

Posting is synchronous: Post returns after every registered receiver has handled the notification.

Observer Types

Method	Behavior
`AddObserver(observer, name)`	Receives every notification posted under `name` until removed.
`AddDisposableObserver(observer, name)`	Receives `name` once; all disposable observers of that name are dropped after the post.
`AddUniversalObserver(observer)`	Receives every notification, regardless of name.

API Reference