键盘上的NSNotificationCenter Swift 3.0显示和隐藏

I am trying to run a function when the keyboard shows and disappears and have the following code:

我正在尝试在键盘显示和消失时运行一个函数并具有以下代码:

let notificationCenter = NotificationCenter.default
notificationCenter.addObserver(self, selector: #selector(ViewController.keyBoardUp(Notification :)), name:  NSNotification.Name.UIKeyboardWillShow, object: nil)

And the function keyBoardUp below:

并且函数keyBoardUp如下:

func keyBoardUp( Notification: NSNotification){
    print("HELLO")
}

However the function doesn't print to the console when the keyboard shows. Help would be greatly appreciated

但是,当键盘显示时,该功能不会打印到控制台。非常感谢帮助

4 个解决方案

#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
        }
    }
}

#2

set keyboard notification observer in

设置键盘通知观察器

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

并在您的函数中处理它

func keyboardNotification(notification: NSNotification) {
  print("keyboard displayed!!")
}

hope this will help you.

希望这会帮助你。

#3

Swift 4.2+

@vandana's answer updated to reflect changes to native Notifications in Swift 4.2.

@ vandana的答案已更新,以反映Swift 4.2中对本机通知的更改。

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)

}

func keyboardWillShow(notification: Notification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] 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?[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.

此外,您需要使用UIKeyboardFrameEndUserInfoKey来解释iOS 11引入的safeAreaInset更改。

#4

Updated for swift:

针对swift进行了更新:

// MARK:- Kyeboard hide/show methods

func keyboardWasShown(_ 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
        }
    }
}

func keyboardWillBeHidden(_ 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
        }
    }
}

func registerForKeyboardNotifications(){
    //Adding notifies on keyboard appearing
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWasShown(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

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

func deregisterFromKeyboardNotifications(){
    //Removing notifies on keyboard appearing
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

func textFieldDidBeginEditing(_ textField: UITextField) {
    if textField == mEnterPasswordTextField || textField == mEnterConfirmPassword  {
            animateViewMoving(up: true, moveValue: 120)
    }
}

func textFieldDidEndEditing(_ textField: UITextField) {
    if textField == mEnterPasswordTextField || textField == mEnterConfirmPassword  {
            animateViewMoving(up: false, moveValue: 120)
    }
}

func animateViewMoving (up:Bool, moveValue :CGFloat){
    let movementDuration:TimeInterval = 0.3
    let movement:CGFloat = ( up ? -moveValue : moveValue)
    UIView.beginAnimations( "animateView", context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(movementDuration )
    self.view.frame = self.view.frame.offsetBy(dx: 0,  dy: movement)
    UIView.commitAnimations()
}

// In viewDidLoad()

//在viewDidLoad()中

self.registerForKeyboardNotifications()
self.deregisterFromKeyboardNotifications()