نشر الإشعارات ومراقبتها

NotificationCenter

المركز الافتراضي

import Foundation

let center = NotificationCenter.default
print("Using the default notification center")

تعريف اسم إشعار

import Foundation

extension Notification.Name {
    static let dataUpdated = Notification.Name("dataUpdated")
}
print("Defined a notification name")

إرسال إشعار

import Foundation

let center = NotificationCenter.default
let name = Notification.Name("ping")
center.post(name: name, object: nil)
print("Posted a notification")

إضافة مراقب (closure)

import Foundation

let center = NotificationCenter.default
let name = Notification.Name("ping")
let token = center.addObserver(forName: name, object: nil, queue: .main) { _ in
    print("Observer fired")
}
center.post(name: name, object: nil)
_ = token

المراقبون المعتمدون على selector

import Foundation

class Watcher: NSObject {
    func start() {
        NotificationCenter.default.addObserver(
            self, selector: #selector(handle(_:)),
            name: Notification.Name("ping"), object: nil)
    }
    @objc func handle(_ n: Notification) { print("Handled") }
}
Watcher().start()

استقبال الإشعار

import Foundation

let center = NotificationCenter.default
let name = Notification.Name("event")
_ = center.addObserver(forName: name, object: nil, queue: nil) { note in
    print("Got: \(note.name.rawValue)")
}
center.post(name: name, object: nil)

بث من واحد إلى عدة أطراف

import Foundation

let center = NotificationCenter.default
let name = Notification.Name("refresh")
_ = center.addObserver(forName: name, object: nil, queue: nil) { _ in print("A") }
_ = center.addObserver(forName: name, object: nil, queue: nil) { _ in print("B") }
center.post(name: name, object: nil)

التصفية حسب object

import Foundation

let center = NotificationCenter.default
let sender = NSObject()
let name = Notification.Name("scoped")
_ = center.addObserver(forName: name, object: sender, queue: nil) { _ in
    print("Only from sender")
}
center.post(name: name, object: sender)

إشعارات النظام

import Foundation

// e.g. UIApplication.didEnterBackgroundNotification on iOS
let custom = Notification.Name("appReady")
_ = NotificationCenter.default.addObserver(forName: custom, object: nil, queue: nil) { _ in
    print("App ready")
}

متى تستخدمه

import Foundation

// Broadcast a global event many parts of the app care about.
let name = Notification.Name("userLoggedOut")
NotificationCenter.default.post(name: name, object: nil)
print("Broadcast logout")

تحقق سريع

مراجعة