NSNotificationCenter Swift 3.0 on keyboard show and hide
Solution 1
Swift 3:
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: Notification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: Notification.Name.UIKeyboardWillHide, object: nil)
}
func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
print("notification: Keyboard will show")
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
Swift 4.2.1:
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
@objc fileprivate func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
// Do something with size
}
}
@objc fileprivate func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
// Do something with size
}
}
Swift 4.2+
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0{
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
Solution 2
Swift 4.2+
@vandana's answer updated to reflect changes to native Notifications in Swift 4.2.
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(ViewController.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}
@objc func keyboardWillShow(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y == 0 {
self.view.frame.origin.y -= keyboardSize.height
}
}
}
@objc func keyboardWillHide(notification: Notification) {
if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
if self.view.frame.origin.y != 0 {
self.view.frame.origin.y += keyboardSize.height
}
}
}
Also, you need to use UIKeyboardFrameEndUserInfoKey
to account for safeAreaInset
changes introduced with iOS 11.
Solution 3
set keyboard notification observer in
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardNotification(notification:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
}
and in your function handle it
func keyboardNotification(notification: NSNotification) {
print("keyboard displayed!!")
}
hope this will help you.
Solution 4
Swift 4.X / 5
I like the inline, block-based approach which is available for a long time already! You can read more about the parameters of addObserver(...)
here.
Some advantages of this approach are:
- you don't need to use the @objc keyword
- you write your callback code at the same location where you setup your observer
Important: Call
NotificationCenter.default.removeObserver(observer)
in thedeinit
of the object where you set register the observer (often a view controller).
let center = NotificationCenter.default
let keyboardWillShowObserver: NSObjectProtocol = center.addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: nil) { (notification) in
guard let value = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
let height = value.cgRectValue.height
// use the height of the keyboard to layout your UI so the prt currently in
// foxus remains visible
}
let keyboardWillHideObserver: NSObjectProtocol = center.addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: nil) { (notification) in
// restore the layout of your UI before the keyboard has been shown
}
Solution 5
KeyBoard Will Show And Hide With TxtField In Swift 4
class ViewController: UIViewController {
@IBOutlet weak var commentsTxt: UITextField!
@IBOutlet weak var keyboardBottom: NSLayoutConstraint!
override func viewWillAppear(_ animated: Bool) {
IQKeyboardManager.shared.enable = false
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboardWillShow),
name: UIResponder.keyboardWillShowNotification,
object: nil
)
NotificationCenter.default.addObserver(
self,
selector: #selector(keyboarddidHide),
name: UIResponder.keyboardWillHideNotification,
object: nil
)
}
@objc func keyboardWillShow(_ notification: Notification) {
if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
let keyboardRectangle = keyboardFrame.cgRectValue
let keyboardHeight = keyboardRectangle.height
self.keyboardBottom.constant = keyboardHeight - self.bottomLayoutGuide.length
DispatchQueue.main.asyncAfter(deadline: .now()+0.1, execute: {
let bottomOffset = CGPoint(x: 0, y: self.scrlView.contentSize.height - self.scrlView.bounds.size.height)
self.scrlView.setContentOffset(bottomOffset, animated: true)
})
}
}
@objc func keyboarddidHide(_ notification: Notification) {
self.keyboardBottom.constant = 0
}
override func viewWillDisappear(_ animated: Bool) {
IQKeyboardManager.shared.enable = true
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}
}
Dhwanit Zaveri
Updated on July 05, 2022Comments
-
Dhwanit Zaveri almost 2 years
I am trying to run a function when the keyboard shows and disappears and have the following code:
let notificationCenter = NotificationCenter.default notificationCenter.addObserver(self, selector: #selector(ViewController.keyBoardUp(Notification :)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
And the function
keyBoardUp
below:func keyBoardUp( Notification: NSNotification){ print("HELLO") }
However the function doesn't print to the console when the keyboard shows. Help would be greatly appreciated