Messenger
Basics
Toolbox implements a publisher-subscriber pattern, that allows you to write minimally coupled code in fewer lines. You can read more about publisher-subscriber pattern Here.
To use this pattern you need to work with Messenger class, which allows you to subscribe and send messages by calling Messenger.Subscribe<T>(...) and Messenger.Send<T>() correspondingly.
Message
To work with messages you need to create one. Message is a basic class for all messages, just derive your message from it, add fields and properties and that's it.
public class PlayerReloadingMessage: Message { }
public class EnemyDiedMessage: Message
{
public Enemy enemy;
}
Subscribing
To subscribe to a message, you need provide its type and a callback to a Messenger.Subscribe<T>(...) method.
...
protected override void Rise()
{
Toolbox.Messenger.Subscribe<PlayerReloadingMessage>(_ => OnPlayerReloading());
Toolbox.Messenger.Subscribe<EnemyDiedMessage>(m => OnEnemyDied(m));
}
private void OnPlayerReloading()
{
// Do something when player reloading
}
private void OnEnemyDied(Enemy enemy)
{
m_KilledEnemies.Add(enemy);
}
...
You can provide type you need in two ways:
- By passing type as Generic argument:
Toolbox.Messenger.Subscribe<SomeMessage>(...) - By passing type directly (in case you have instance of a message you want to subscribe to):
Toolbox.Messenger.Subscribe(_someMessage.GetType(), ...)
Sending
You can send messages in several ways:
By type
If you do not have additional data to provide with message, you can just provide message's type.
By instance
If you want to pass additional data to a message, you need to create an instance of it and provide it as a parameter.
By cached variable
If you often send a one type of message with different data, you can cache it and send it without creating a new instance.
...
private GainedXPMessage _gainedXPMessage = new GainedXPMessage();
...
public void OnXpGained(int amount)
{
//do related stuff
//update message's variable
m_GainedXPMessage.amount = amount;
//then send a message
Toolbox.Messenger.Send(_gainedXPMessage);
}
...
Subscriber object
Every time you subscribing to a message by Subscribe method it returns Subscriber object, which defines this subscription. You can use it to manually unsubscribe from it.
...
private Subscriber _damageTakenSubscriber;
...
public void Awake()
{
_damageTakenSubscriber = Toolbox.Messenger.Subscribe<DamageTakenMessage>(...);
}
...
public void OnDestroy()
{
Toolbox.Messenger.RemoveSubscriber(_damageTakenSubscriber);
}
You can also remove list or array of subscribers by calling Toolbox.Messenger.RemoveSubscribers(_listOfSubscribers).
To remove all subscribers just call Toolbox.Messenger.ClearSubscribers().
Binding
You can bind your subscribe to a gameobject lifetime, so it will be automatically removed if gameobject destroyed to prevent memory leaks and errors. Just provide gameobject you want to bind as second parameter.