How to pass data using NotificationCenter in swift 3.0 and NSNotificationCenter in swift 2.0?

Swift 2.0

Pass info using userInfo which is a optional Dictionary of type [NSObject : AnyObject]?

  let imageDataDict:[String: UIImage] = ["image": image]  // Post a notification  NSNotificationCenter.defaultCenter().postNotificationName(notificationName, object: nil, userInfo: imageDataDict) // Register to receive notification in your class NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: notificationName, object: nil) // handle notification func showSpinningWheel(notification: NSNotification) {   if let image = notification.userInfo?["image"] as? UIImage {  // do something with your image     } }

Swift 3.0, 4.0, 5.0 version and above

The userInfo now takes [AnyHashable: Any]? as an argument, which we provide as a dictionary literal in Swift

  let imageDataDict:[String: UIImage] = ["image": image]  // post a notification  NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)   // `default` is now a property, not a method call // Register to receive notification in your class NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil) // handle notification // For swift 4.0 and above put @objc attribute in front of function Definition   func showSpinningWheel(_ notification: NSNotification) {  if let image = notification.userInfo?["image"] as? UIImage {  // do something with your image     } }

NOTE: Notification “names” are no longer strings, but are of type Notification.Name, hence why we are using NSNotification.Name(rawValue: "notificationName") and we can extend Notification.Name with our own custom notifications.

extension Notification.Name {static let myNotification = Notification.Name("myNotification")}// and post notification like thisNotificationCenter.default.post(name: .myNotification, object: nil)

For Swift 3

let imageDataDict:[String: UIImage] = ["image": image]  // post a notification  NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)   // `default` is now a property, not a method call // Register to receive notification in your class NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil) // handle notification func showSpinningWheel(_ notification: NSNotification) {        print(notification.userInfo ?? "")        if let dict = notification.userInfo as NSDictionary? {            if let id = dict["image"] as? UIImage{                // do something with your image            }        } }

For Swift 4

let imageDataDict:[String: UIImage] = ["image": image]  // post a notification  NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)   // `default` is now a property, not a method call // Register to receive notification in your class NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil) // handle notification @objc func showSpinningWheel(_ notification: NSNotification) {        print(notification.userInfo ?? "")        if let dict = notification.userInfo as NSDictionary? {            if let id = dict["image"] as? UIImage{                // do something with your image            }        } }

Hello @sahil I update your answer for swift 3

let imageDataDict:[String: UIImage] = ["image": image]  // post a notification  NotificationCenter.default.post(name: NSNotification.Name(rawValue: "notificationName"), object: nil, userInfo: imageDataDict)   // `default` is now a property, not a method call // Register to receive notification in your class NotificationCenter.default.addObserver(self, selector: #selector(self.showSpinningWheel(_:)), name: NSNotification.Name(rawValue: "notificationName"), object: nil) // handle notification func showSpinningWheel(_ notification: NSNotification) {        print(notification.userInfo ?? "")        if let dict = notification.userInfo as NSDictionary? {            if let id = dict["image"] as? UIImage{                // do something with your image            }        } }

Hope it's helpful. Thanks