CODEWITHSUNDEEP
iosswiftclosuresnsnotificationcenter
MKiOS
MKiOS

Reputation: 73

Notification observers are not working in closures in swift

NotificationCenter.default.post is not working in closures

I am having a class with the notification observers

     NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("Start"), object: nil)

     NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("Stop"), object: nil)

     NotificationCenter.default.addObserver(self, selector: #selector(self.methodOfReceivedNotification(notification:)), name: Notification.Name("Interrupt"), object: nil)

In the same class having a method to handle the notification

@objc func methodOfReceivedNotification(notification: Notification) {
    print("Notification Received")
}

When I am trying to post the observer from another class with the below code it is working fine

    NotificationCenter.default.post(name: Notification.Name("Start"), object: nil)

But when trying to post the same thing inside the closure response of the network method it is not calling the methodOfReceivedNotification

Closure code

       executeHttpReq(url: getUIUrl(), getparametersDict: getParameters, onSuccess: { (response, status,isEod) -> (
        Any, String,Bool) in

    NotificationCenter.default.post(name: Notification.Name("Start"), object: nil)
        return (response,status,isEod)
    }, onFailure: { (error) in
        //todo send stop event to the caller

        NotificationCenter.default.post(name: Notification.Name("Stop"), object: nil)

    })

Is there any wrong in the code please suggest.

Upvotes: 5

Views: 4089

Answers (2)

Ashish Rana
Ashish Rana

Reputation: 60

  1. Create extension
extension Notification.Name {
    static let Start = Notification.Name("Start")
    static let Stop = Notification.Name("Stop")
}
  1. Add following code in viewDidLoad 
NotificationCenter.default.addObserver(self, selector: #selector(onDidReceiveData(_:)), name: .Start, object: nil)
  1. Add function in your viewController
 @objc func onDidReceiveData(_ notification:Notification) {
        print("image deleted by user")
       // self.isExcluded = true
   }
  1. Fire notification in main queue
DispatchQueue.main.async {
   NotificationCenter.default.post(name: .Start, object: nil)
}

Tried with my existing code.

RequestManager.shared.doPost(strURL:url, parameter: params) { (response, error) in
            guard error == nil else {
                return
            }
            do {
                if let isSucess = response!["IsSuccessStatusCode"] as? Bool{

                    if isSucess == true{

                                DispatchQueue.main.async {


                                    NotificationCenter.default.post(name: .Start, object: nil)

                                }
                            }
                        }
                    }
                    else{
                        self.showValidationAlert(message: "Try after some time")
                    }
                }
                else{
                    self.showValidationAlert(message: "Try after some time")
                }
            }

        }
    }

Upvotes: 1

Anand
Anand

Reputation: 1946

Try posting the notification in Main queue when it is inside closure.

DispatchQueue.main.async {
   NotificationCenter.default.post(name: Notification.Name("Start"), object: nil)
}

Upvotes: 5

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