Passing Data Using NotificationCenter in Swift 4

Posted on | Edited on

Passing data from one view controller to another view controller using Notification Center is an easy way when compared to delegate protocols.

Here we need add observer or listeners for getting new data to load. First we need to send data using post notification method.

Sending Data - Post Notification:

1
let dataToSend = ["name" : "John", "age" : 25] as [String : Any]
1
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "newDataToLoad"), object: dataToSend)

Before sending data we need to listen for the above notification using NSNotification.Name

Data Receiving - Add observer:

Add the following code for listening to new data:

1
NotificationCenter.default.addObserver(self, selector: #selector(notificationRecevied(notification:)), name: NSNotification.Name(rawValue: "newDataToLoad"), object: nil)

Add the following method to retrieve data:

1
2
3
@objc func notificationRecevied(notification: Notification) {
    let data = notification.object
}

Remove Observer:

Don’t forgot to remove observer onviewWillDisappear()as follow:

1
NotificationCenter.default.removeObserver(self, name: NSNotification.Name(rawValue: "newDataToLoad"), object: nil)

Source: iosrevisited