Swift 3 Nsnotificationcenter Keyboardwillshow/Hide

Swift 3 NSNotificationCenter Keyboardwillshow/hide

Check out the updated Swift Programming Language book. Pages 1027 and 1028 are what you're looking for. It should be something like this:

func keyboardWillHide(_ notification: NSNotification) {…

Notice the additional underscore above. Also:

#selector(LoginViewController.keyboardWillHide(_:))

You also might need to add @objc(keyboardWillHideWithNotification:) to your class.

How to write Keyboard notifications in Swift 3

Swift 4

override func viewDidLoad() {
    super.viewDidLoad()   
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

func keyboardWillShow(notification: NSNotification) {
     print("keyboardWillShow")
}

func keyboardWillHide(notification: NSNotification){
     print("keyboardWillHide")
}

deinit {
     NotificationCenter.default.removeObserver(self)
}

You can also get keyboard info using below code inside these methods.

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil) .      

@objc func keyboardWillChange(notification: NSNotification) {
     let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
     let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
     let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
     let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
     let deltaY = targetFrame.origin.y - curFrame.origin.y
 }

Notification centre for keyboard show/hide not working in iOS 11

Try this updated syntax instead for your observers:

func registerNotificationObservers() {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector:#selector(keyboardWillHide), name: .UIKeyboardWillHide, object: nil)
}

func removeNotificationObservers() {
    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
}

@objc func keyboardWillShow(_ notification: Notification) {
    print("keyboardWillShow")
}

@objc func keyboardWillHide(_ notification: Notification) {
    print("keyboardWillHide")
}

How to write Keyboard notifications in Swift 4.2?

Just replace .UIResponder.keyboardDidShowNotification with UIResponder.keyboardDidShowNotification and it will solve your problem.

And final code will be:

NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardDidShow), name: UIResponder.keyboardDidShowNotification, object: nil)

How do I use #selector?

In Swift 3, it looks like this:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)

Get sender on NotificationCenter keyboard will show

In iOS you can figure out who has the keyboard focus with UIResponder.isFirstResponder (note all UIViews inherit from UIResponder, so its a property on every view). Just check which field has isFirstResponder = true and scroll to that one. Its useful to put all of your fields into an outlet collection if you have a lot of them so you can just iterate through them and figure out which one isFirstResponder.

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 an optional Dictionary of type [NSObject : AnyObject]?

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   
    }
}

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 this
NotificationCenter.default.post(name: .myNotification, object: nil)

View Responsiveness on Keyboard Show and Hide Ios Swift 4

The simple solution is to use IQKeyboardManagerSwift.

pod 'IQKeyboardManagerSwift' // add this in your pod file.

Add the following code in didFinishLaunchingWithOptions.

IQKeyboardManager.shared.enable = true

I hope this helps.

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