How to detect when keyboard is shown and hidden

Question

How can I detect when the keyboard is shown and hidden from my application

User · Answer

You ll want to register yourself for the 2 keyboard notifications     NSNotificationCenter defaultCenter  addObserver self selector  selector keyboardDidShow   name  UIKeyboardDidShowNotification object nil     NSNotificationCenter defaultCenter  addObserver self selector  selector  keyboardDidHide   name  UIKeyboardDidHideNotification object nil     Great post on how to adjust your TextField to the keyboard - http   iosdevelopertips com user-interface adjust-textfield-hidden-by-keyboard html

User · Answer

Swift 3   NotificationCenter default addObserver self  selector   selector viewController keyboardWillShow       name  NSNotification Name UIKeyboardWillShow  object  nil  NotificationCenter default addObserver self  selector   selector viewController keyboardWillHide       name  NSNotification Name UIKeyboardWillHide  object  nil   func keyboardWillShow   notification  NSNotification          Do something here    func keyboardWillHide   notification  NSNotification          Do something here

User · Answer

In Swift 4 2 the notification names have moved to a different namespace  So now it s  override func viewWillAppear   animated  Bool        super viewWillAppear animated      addKeyboardListeners       override func viewWillDisappear   animated  Bool        super viewWillDisappear animated      NotificationCenter default removeObserver self      func addKeyboardListeners         NotificationCenter default addObserver self  selector   selector keyboardWillHide   name  UIResponder keyboardWillHideNotification  object  nil      NotificationCenter default addObserver self  selector   selector keyboardWillShow   name  UIResponder keyboardWillShowNotification  object  nil      objc private extension WhateverTheClassNameIs        func keyboardWillShow   notification  Notification               Do something here             func keyboardWillHide   notification  Notification               Do something here

User · Answer

If you have more then one UITextFields and you need to do something when  or before  keyboard appears or disappears  you can implement this approach   Add UITextFieldDelegate to your class  Assign integer counter  let s say   NSInteger editCounter     Set this counter to zero somewhere in viewDidLoad  Then  implement textFieldShouldBeginEditing and textFieldShouldEndEditing delegate methods   In the first one add 1 to editCounter  If value of editCounter becomes 1 - this means that keyboard will appear  in case if you return YES   If editCounter   1 - this means that keyboard is already visible and another UITextField holds the focus   In textFieldShouldEndEditing subtract 1 from editCounter  If you get zero - keyboard will be dismissed  otherwise it will remain on the screen

User · Answer

You could use KBKeyboardObserver library  It contains some examples and provides simple interface

User · Answer

Swift 4     NotificationCenter default addObserver  self  selector   selector ControllerClassName keyboardWillShow         name  Notification Name UIKeyboardWillShow    object  nil    NotificationCenter default addObserver self  selector   selector ControllerClassName keyboardWillHide         name  Notification Name UIKeyboardWillHide    object  nil    Next  adding method to stop listening for notifications when the object   s life ends -  Then add the promised methods from above to the view controller  deinit     NotificationCenter default removeObserver self    func adjustKeyboardShow   open  Bool  notification  Notification      let userInfo   notification userInfo          let keyboardFrame    userInfo UIKeyboardFrameBeginUserInfoKey  as  NSValue  cgRectValue   let height    keyboardFrame height   20     open   1   -1    scrollView contentInset bottom    height   scrollView scrollIndicatorInsets bottom    height     objc func keyboardWillShow   notification  Notification      adjustKeyboardShow true  notification  notification     objc func keyboardWillHide   notification  Notification      adjustKeyboardShow false  notification  notification

User · Answer

There is a CocoaPods to facilitate the observation on NSNotificationCentr for the keyboard s visibility here  https   github com levantAJ Keyhi  pod  Keyhi

User · Answer

So ah  this is the real answer now  import Combine   class MrEnvironmentObject           Bind into yr SwiftUI views      Published public var isKeyboardShowing  Bool   false          Keep  em from deallocatin      var subscribers   AnyCancellable     nil          Adds certain Combine subscribers that will handle updating the           isKeyboardShowing  property                  - Parameter host  the UIHostingController of your views       func setupSubscribers lt V  View gt           host  inout UIHostingController lt V gt                  subscribers                 NotificationCenter                  default                  publisher for  UIResponder keyboardWillShowNotification                   sink    weak self    in                     self  isKeyboardShowing   true                                NotificationCenter                  default                  publisher for  UIResponder keyboardWillHideNotification                   sink    weak self  weak host    in                     self  isKeyboardShowing   false                        Hidden gem  ask me how I know                      UIAccessibility post                          notification   layoutChanged                           argument  host                                                                         Profit                  sink    weak self  profit in profit

User · Answer

In the ViewDidLoad method of your class set up to listen for messages about the keyboard      Listen for keyboard appearances and disappearances   NSNotificationCenter defaultCenter  addObserver self                                           selector  selector keyboardDidShow                                                name UIKeyboardDidShowNotification                                            object nil      NSNotificationCenter defaultCenter  addObserver self                                          selector  selector keyboardDidHide                                                name UIKeyboardDidHideNotification                                            object nil     Then in the methods you specify  in this case keyboardDidShow and keyboardDidHide  you can do something about it   -  void keyboardDidShow   NSNotification    notif         Do something here    -  void keyboardDidHide   NSNotification    notif         Do something here

User · Answer

You may just need addObserver in viewDidLoad  But having addObserver in viewWillAppear and removeObserver in viewWillDisappear prevents rare crashes which happens when you are changing your view   Swift 4 2  override func viewWillAppear   animated  Bool        super viewWillAppear animated      NotificationCenter default addObserver self  selector   selector keyboardWillDisappear   name  UIResponder keyboardWillHideNotification  object  nil      NotificationCenter default addObserver self  selector   selector keyboardWillAppear   name  UIResponder keyboardWillShowNotification  object  nil      objc func keyboardWillAppear           Do something here     objc func keyboardWillDisappear           Do something here    override func viewWillDisappear   animated  Bool        super viewWillDisappear animated      NotificationCenter default removeObserver self      Swift 3 and 4  override func viewWillAppear   animated  Bool        super viewWillAppear animated      NotificationCenter default addObserver self  selector   selector keyboardWillDisappear   name  Notification Name UIKeyboardWillHide  object  nil      NotificationCenter default addObserver self  selector   selector keyboardWillAppear   name  Notification Name UIKeyboardWillShow  object  nil      objc func keyboardWillAppear           Do something here     objc func keyboardWillDisappear           Do something here    override func viewWillDisappear   animated  Bool        super viewWillDisappear animated      NotificationCenter default removeObserver self      Older Swift  override func viewWillAppear animated  Bool        super viewWillAppear animated       NSNotificationCenter defaultCenter   addObserver self  selector  keyboardWillAppear    name  UIKeyboardWillShowNotification  object  nil      NSNotificationCenter defaultCenter   addObserver self  selector  keyboardWillDisappear    name  UIKeyboardWillHideNotification  object  nil     func keyboardWillAppear notification  NSNotification          Do something here    func keyboardWillDisappear notification  NSNotification          Do something here    override func viewWillDisappear animated  Bool        super viewWillDisappear animated      NSNotificationCenter defaultCenter   removeObserver self

User · Answer

Check out the Managing the Keyboard section of the  Text  Web  and Editing Programming Guide  for information on tracking the keyboard being shown or hidden  and how to display dismiss it manually

User · Answer

Swift - 4  override func viewWillAppear   animated  Bool       super viewWillAppear animated     addKeyBoardListener      override func viewWillDisappear   animated  Bool        super viewWillDisappear animated      NotificationCenter default removeObserver self    remove observer    func addKeyBoardListener         NotificationCenter default addObserver self  selector   selector self keyboardWillShow       name  NSNotification Name UIKeyboardWillShow  object  nil       NotificationCenter default addObserver self  selector   selector self keyboardWillHide       name  NSNotification Name UIKeyboardWillHide  object  nil       objc func keyboardWillShow   notification  Notification         objc func keyboardWillHide   notification  Notification

User · Answer

Swift 4 - dd 20 october 2017  override func viewDidLoad                   NotificationCenter default addObserver self  selector   selector keyboardWillDisappear       name  Notification Name UIKeyboardWillHide  object  nil      NotificationCenter default addObserver self  selector   selector keyboardWillAppear       name  Notification Name UIKeyboardWillShow  object  nil      objc func keyboardWillAppear   notification  NSNotification        if let userInfo   notification userInfo          let keyboardFrame    userInfo UIKeyboardFrameEndUserInfoKey  as  NSValue  cgRectValue              let inset   keyboardFrame height    if scrollView is not aligned to bottom of screen  subtract offset            scrollView contentInset bottom   inset            scrollView scrollIndicatorInsets bottom   inset           objc func keyboardWillDisappear   notification  NSNotification        scrollView contentInset bottom   0     scrollView scrollIndicatorInsets bottom   0    deinit       NotificationCenter default removeObserver self

User · Answer

Swift 5  There answers above are correct  Although I would prefer to create a helper to wrap up the notification s observers    The benefit    You don t have to repeat each time you handle the keyboard behaviors  You can extend other notification by implement other enum value It s useful when you have to deal with keyboard in several controllers    Sample code   extension KeyboardHelper       enum Animation           case keyboardWillShow         case keyboardWillHide            typealias HandleBlock      animation  Animation    keyboardFrame  CGRect    duration  TimeInterval  - gt  Void    final class KeyboardHelper       private let handleBlock  HandleBlock      init handleBlock   escaping HandleBlock            self handleBlock   handleBlock         setupNotification              deinit           NotificationCenter default removeObserver self             private func setupNotification                 NotificationCenter default              addObserver forName  UIResponder keyboardWillShowNotification  object  nil  queue   main     weak self  notification in                 self  handle animation   keyboardWillShow  notification  notification                             NotificationCenter default              addObserver forName  UIResponder keyboardWillHideNotification  object  nil  queue   main     weak self  notification in                 self  handle animation   keyboardWillHide  notification  notification                           private func handle animation  Animation  notification  Notification            guard let userInfo   notification userInfo              let keyboardFrame    userInfo UIResponder keyboardFrameEndUserInfoKey  as  NSValue   cgRectValue              let duration   userInfo UIResponder keyboardAnimationDurationUserInfoKey  as  Double         else   return            handleBlock animation  keyboardFrame  duration            How to use   private var keyboardHelper  KeyboardHelper       override func viewDidLoad               keyboardHelper   KeyboardHelper    unowned self  animation  keyboardFrame  duration in         switch animation           case  keyboardWillShow              print  keyboard will show           case  keyboardWillHide              print  keyboard will hide

[ios] How to detect when keyboard is shown and hidden

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