In App Development some time we need internal communication to pass message to one ViewController to other ViewController. As Example. I am using Google login using Firebase now login task doing AppDelegate Now i need message when login success or fail on ViewController. Then here we can use NSNotificationCenter.
1. Create Globally define a"Special Notification Key" constant that can be broadcast. on ViewController
3. Create Func that can call when Notify ViewController
That's it.
1. Create Globally define a"Special Notification Key" constant that can be broadcast. on ViewController
let mySpecialNotificationKey = "com.arkay.specialNotificationKey"2. Set Observer on ViewController.
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.updateNotificationSentLabel), name: NSNotification.Name(rawValue: mySpecialNotificationKey), object: nil)
3. Create Func that can call when Notify ViewController
func updateNotificationSentLabel(){
btnSignIn.setTitle("Login Out",for: .normal)
}]
4. Now Call When need. Right now i am calling from AppDelegate.NotificationCenter.default.post(name: Notification.Name(rawValue: mySpecialNotificationKey), object: self)
That's it.
