如何在iOS类中注册通知中心

Question

I am new to ios programming, I wanted to register notification center in the class, not in the view controller, I want to send some action from one view controller this custom class receives that action and it performs some view controller navigation.I wanted to have custom notification center in ios.

code:

NotificationCenter.default.post(name: Notification.Name(rawValue: "key"), object: nil)
class MainReceiver: NotificationCenter
{
    override func post(name aName: NSNotification.Name, object anObject: Any?)
    {
        print("coming here")
    }

}

Answer 1

Here you have snipped code:

class MainReceiver {

    init() {

        NotificationCenter.default.addObserver(self, selector: #selector(handleMethod(_:)), name: NSNotification.Name(rawValue: "Notification_Name"), object: nil)
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    @objc func handleMethod(_ notification: Notification) {
        // handle
    }
}

Answer 2

From Apple's NSNotificationCenter documentation :

Each running Cocoa program has a default notification center. You typically don't create your own.

I'm not sure why you think you want to create your own notification center, but trust me, you don't.

---

However, you can easily subscribe an object (an instance of a custom class, like you say you want to use) to notifications:

// let object = Whatever()
NotificationCenter.default.addObserver(object, selector: #selector(didReceive(notification:)), name: NSNotification.Name(rawValue: "key"), object: nil)
// object's didReceive(notification:) function will now be called when a notification with the specified name is posted. This can be posted from anywhere.

A while back, the function had to be decorated with the @objc attribute. I'm not sure if that's still the case, but if so, you'd use @objc func didReceive(notification: Notification) as your declaration in the receiving class.

Answer 3

If I understand your question correctly I think what you are looking for is the blocked based variant for the NotificationCenter.

You can find it in the official docs .

Example code from the docs:

let center = NSNotificationCenter.defaultCenter()
let mainQueue = NSOperationQueue.mainQueue()
self.localeChangeObserver = center.addObserverForName(NSCurrentLocaleDidChangeNotification, object: nil, queue: mainQueue) { (note) in
print("The user's locale changed to: \(NSLocale.currentLocale().localeIdentifier)")