Crex
Crex is an library for simple and type safe usage of Notification Center. Posting extra information is so handy due to code completion.
Example
To run the example project, clone the repo, and run pod install from the Example directory first.
Requirements
-
iOS 9.3+
-
Swift 4.1
Installation
Crex is available through CocoaPods. To install
it, simply add the following line to your Podfile:
pod 'Crex'
Usage
Definig Event
import Crex
struct QueueStateChanged: CrexEvent {
typealias PayloadType = QueueStateChanged.Payload
static let notificationName = NSNotification.Name(rawValue: "MyApp.QueueStateChanged")
static let transformation: CrexTransformation = nil
struct Payload {
let updatedAt = Date()
let itemsLeft: Int
}
}Registering observer
Crex<QueueStateChanged>.addObserver { (_, queueState) in
guard let queueState = queueState else {
return
}
print("Queue updated: \(queueState.updatedAt), items left: \(queueState.itemsLeft)")
}Posting event
Crex<QueueStateChanged>.post(QueueStateChanged.Payload(itemsLeft: 42))Using system notifications
struct ApplicationDidBecomeActive: CrexEvent {
typealias PayloadType = Void
static let notificationName: NSNotification.Name = .UIApplicationDidBecomeActive
static let transformation: CrexTransformation = nil
}
Crex<ApplicationDidBecomeActive>.addObserver { (_, _) in
print("Application did become active")
}Using transformation
Sometimes it is enough to just take some bits of data passed iside notification sent from system. Also in this approach we are not creating duplication when fetching data from userInfo dictionary.
struct KeyboardWillShow: CrexEvent {
typealias PayloadType = KeyboardWillShow.KeyboardPayload
static let notificationName: NSNotification.Name = .UIKeyboardWillShow
static let transformation: CrexTransformation = { (userInfo: CrexUserInfo) in
guard let keyboardSize = userInfo[UIKeyboardFrameBeginUserInfoKey] as? CGRect,
let animationDuration = userInfo[UIKeyboardAnimationDurationUserInfoKey] as? TimeInterval else {
return nil
}
return KeyboardPayload(height: keyboardSize.height, animationDuration: animationDuration)
}
struct KeyboardPayload {
let height: CGFloat
let animationDuration: TimeInterval
}
}
Crex<KeyboardWillShow>.addObserver { (_, keyboard) in
guard let keyboard = keyboard else {
return
}
print("Will show keyboard height: \(keyboard.height), duration: \(keyboard.animationDuration)")
}Author
Marek Rogowski, [email protected]
License
Crex is available under the MIT license. See the LICENSE file for more info.