CODEWITHSUNDEEP
objective-cswiftselectornsnotificationcenternotificationcenter
ndPPPhz
ndPPPhz

Reputation: 325

Unrecognized Selector NotificationCenter Swift 3

I've read all of the possible solutions on stack overflow but not one works for me.

My code is

func foo() {
    NotificationCenter.default.addObserver(self, selector: #selector(fetchedUser(notification:)) , name: NSNotification.Name.init("dbReady"), object: nil)
    loggedUser.fetchUserByUID(id: current.uid)    
    return true
}

func fetchedUser(notification:NSNotification){
    let info = notification.object as! [String : AnyObject]
    print(info)
}

And in another class I've:

 NotificationCenter.default.post(name: NSNotification.Name.init("dbReady"), object: dictionary)

All of syntax for selector doesn't work

I tried: 

1. fetchedUser
2. fetchedUser:
3. fetchedUser(notification:)
4. "fetchedUser:"

And other ten options maybe. Can anyone help me?

Upvotes: 0

Views: 748

Answers (5)

vadian
vadian

Reputation: 285069

In Swift 3 the (system) notifications have this standard signature:

func notifFunction(_ notification: Notification)

So your function is supposed to be

func fetchedUser(_ notification: Notification){

And the corresponding selector is 

#selector(fetchedUser(_:))

For convenience you could use an extension of Notification.Name

extension Notification.Name {
  static let databaseReady = NSNotification.Name("dbReady")
}

Then you can write

NotificationCenter.default.addObserver(self, selector: #selector(fetchedUser(_:)) , name: .databaseReady, object: nil)

and

NotificationCenter.default.post(name: .databaseReady, object: dictionary)

Upvotes: 3

Amrit Tiwari
Amrit Tiwari

Reputation: 980

It works on my project.

Post Notification

let dic: [String:AnyObject] = ["news_id": 1 as AnyObject,"language_id" : 2 as AnyObject]
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "NotificationKeyIndentifier"), object: dic)

Notification Observer

Add following code on required class where you want to observe.

NotificationCenter.default.addObserver(self, selector: #selector(self.handlePushNotification(notification:)), name: NSNotification.Name(rawValue: "NotificationKeyIndentifier"), object: nil)

This is the function, which is trigger after observed by the notification observer.

func handlePushNotification(notification: NSNotification){

    if let dic = notification.object as? [String: AnyObject]{

        if let language_id = dic["language_id"] as? Int{

            if let news_id = dic["news_id"] as? Int{
                    print(language_id)
                    print(news_id)
              }
          }
      }
 }

Hope it may help you. If you have any problem regarding this please fill free to ask questions.

Upvotes: 1

Sandeep
Sandeep

Reputation: 21144

class Observer {

    init() {
        let name = NSNotification.Name("TestNotification")
        NotificationCenter.default.addObserver(self, selector: #selector(notificationDidTrigger), name: name, object: nil)
    }

    @objc func notificationDidTrigger(notification: Notification) {
        print("Notification triggered ", notification.userInfo)
    }
}


let obj = Observer()

let name = NSNotification.Name("TestNotification")
var notification = Notification(name: name, object: nil)
notification.userInfo =  ["Name": "My notification"]
NotificationCenter.default.post(notification)

Upvotes: 0

ndPPPhz
ndPPPhz

Reputation: 325

My error was a selector with name didn't exist "fetchedUserWithNotification:". I solved my problem by rewriting a new class and copy and paste all its content. Maybe it was a Xcode bug (IMHO the last version is plenty of it )

Upvotes: 0

Ram
Ram

Reputation: 969

You can try this: 

NotificationCenter.default.addObserver(self, selector: #selector(YourClassName.fetchedUser), name: notificationName, object: nil)

Upvotes: 0

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