A replacement for NSNotificationCenter#addObserver
and NSObject#addObserver
that is type-safe and not verbose.
import EmitterKit
// A generic event emitter (but type-safe)!
var event = Event<T>()
// Any emitted data must be the correct type.
event.emit(data)
// This listener will only be called once.
// You are *not* required to retain it.
event.once { data: T in
print(data)
}
// This listener won't stop listening;
// unless you stop it manually,
// or its Event<T> is deallocated.
// You *are* required to retain it.
var listener = event.on { data: T in
print(data)
}
// Stop the listener manually.
listener.isListening = false
// Restart the listener (if it was stopped).
listener.isListening = true
A target allows you to associate a specific AnyObject
with an emit
call. This is useful when emitting events associated with classes you can't add properties to (like UIView
).
When calling emit
with a target, you must also call on
or once
with the same target in order to receive the emitted event.
let myView = UIView()
let didTouch = Event<UITouch>()
didTouch.once(myView) { touch in
print(touch)
}
didTouch.emit(myView, touch)
The Notifier
class helps when you are forced to use NSNotificationCenter
(for example, if you want to know when the keyboard has appeared).
// You are **not** required to retain this after creating your listener.
var event = Notifier(UIKeyboardWillShowNotification)
// Handle NSNotifications with style!
listener = event.on { (notif: Notification) in
print(notif.userInfo)
}
// Any NSObject descendant will work.
var view = UIView()
// "Make KVO great again!" - Donald Trump
listener = view.on("bounds") { (change: Change<CGRect>) in
print(change)
}
⚠️ None of the classes in EmitterKit are thread-safe!
The following actions must be done on the same thread, or you need manual locking:
isListening
property of a listener
Event.getListeners
methodThe NotificationListener
class now takes a Notification
instead of an NSDictionary
.
A NotificationListener
without a target will now receive every Notification
with its name, regardless of the value of notif.object
.
Swift 3.0 + Xcode 8.0 beta 6 support
The Signal
class was removed. (use Event<Void>
instead)
The Emitter
abstract class was removed.
The EmitterListener
class was renamed EventListener<T>
.
The Event<T>
class no longer has a superclass.
The Notification
class was renamed Notifier
(to prevent collision with Foundation.Notification
).
The on
and once
methods of Event<T>
now return an EventListener<T>
(instead of just a Listener
)
The on
and once
methods of Notifier
now return an NotificationListener
(instead of just a Listener
)
The on
and once
methods of NSObject
now return an ChangeListener<T>
(instead of just a Listener
)
The keyPath
, options
, and object
properties of ChangeListener<T>
are now public.
A listenerCount: Int
computed property was added to the Event<T>
class.
An event: Event<T>
property was added to the EventListener<T>
class.
The changelog for older versions can be found here.