Swift 5解决方案frédéric-adda:

protocol KeyboardHandler: class {
    var bottomConstraint: NSLayoutConstraint! { get set }
    
    func keyboardWillShow(_ notification: Notification)
    func keyboardWillHide(_ notification: Notification)
    func startObservingKeyboardChanges()
    func stopObservingKeyboardChanges()
}


extension KeyboardHandler where Self: UIViewController {

    func startObservingKeyboardChanges() {

        // NotificationCenter observers
        NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillShowNotification, object: nil, queue: nil) { [weak self] notification in
          self?.keyboardWillShow(notification)
        }

        // Deal with rotations
        NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillChangeFrameNotification, object: nil, queue: nil) { [weak self] notification in
          self?.keyboardWillShow(notification)
        }

        // Deal with keyboard change (emoji, numerical, etc.)
        NotificationCenter.default.addObserver(forName: UITextInputMode.currentInputModeDidChangeNotification, object: nil, queue: nil) { [weak self] notification in
          self?.keyboardWillShow(notification)
        }

        NotificationCenter.default.addObserver(forName: UIResponder.keyboardWillHideNotification, object: nil, queue: nil) { [weak self] notification in
          self?.keyboardWillHide(notification)
        }
    }


    func keyboardWillShow(_ notification: Notification) {

      let verticalPadding: CGFloat = 20 // Padding between the bottom of the view and the top of the keyboard

        guard let value = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else { return }
      let keyboardHeight = value.cgRectValue.height

      // Here you could have more complex rules, like checking if the textField currently selected is actually covered by the keyboard, but that's out of this scope.
      self.bottomConstraint.constant = keyboardHeight + verticalPadding

      UIView.animate(withDuration: 0.1, animations: { () -> Void in
          self.view.layoutIfNeeded()
      })
  }


  func keyboardWillHide(_ notification: Notification) {
      self.bottomConstraint.constant = 0

      UIView.animate(withDuration: 0.1, animations: { () -> Void in
          self.view.layoutIfNeeded()
      })
  }


  func stopObservingKeyboardChanges() {
      NotificationCenter.default.removeObserver(self)
  }
}

在任何UIViewController中:

遵循KeyboardHandler协议

extension AnyViewController: KeyboardHandler {} 

为屏幕上最后一个底部元素添加底部约束。

@IBOutlet var bottomConstraint: NSLayoutConstraint! 

添加观察者订阅/取消订阅:

 override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        startObservingKeyboardChanges()
 }
    
 override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        stopObservingKeyboardChanges()
 }

享受吧!

如果你正在使用自动布局，我假设你已经设置了底部空间为Superview约束。如果是这种情况，您只需更新约束的值。这是你如何用一点动画来做到这一点。

func keyboardWasShown(notification: NSNotification) {
    let info = notification.userInfo!
    let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue()

    UIView.animateWithDuration(0.1, animations: { () -> Void in
        self.bottomConstraint.constant = keyboardFrame.size.height + 20
    })
}

添加硬编码的20只是为了将文本框弹出到键盘上方一点。否则键盘的上边距和文本框的下边距将会接触。

当键盘关闭时，将约束的值重置为原始值。

另一个解决方案，不依赖于自动布局，约束或任何出口。您所需要的是滚动视图中的字段。

override func viewDidLoad() {
    super.viewDidLoad()

    NSNotificationCenter.defaultCenter().addObserver(self, selector: "makeSpaceForKeyboard:", name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "makeSpaceForKeyboard:", name: UIKeyboardWillHideNotification, object: nil)
}

func makeSpaceForKeyboard(notification: NSNotification) {
    let info = notification.userInfo!
    let keyboardHeight:CGFloat = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).CGRectValue().size.height
    let duration:Double = info[UIKeyboardAnimationDurationUserInfoKey] as! Double

    if notification.name == UIKeyboardWillShowNotification {
        UIView.animateWithDuration(duration, animations: { () -> Void in
            var frame = self.view.frame
            frame.size.height = frame.size.height - keyboardHeight
            self.view.frame = frame
        })
    } else {
        UIView.animateWithDuration(duration, animations: { () -> Void in
            var frame = self.view.frame
            frame.size.height = frame.size.height + keyboardHeight
            self.view.frame = frame
        })
    }

}

非常简单，不需要编写更多代码。 只需在podfile中添加pod 'IQKeyboardManagerSwift'，并在AppDelegate页面中添加下面的代码。

import IQKeyboardManagerSwift

在方法didFinishLaunchingWithOptions()类型中

IQKeyboardManager.shared.enable = true

就是这样。 查看这个视频链接，以更好地了解https://youtu.be/eOM94K1ZWN8 希望这对你有所帮助。

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    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:Notification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0)
    }
}

func keyboardWillHide(_ notification:Notification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
    }
}

我的做法如下:

class SignInController: UIViewController , UITextFieldDelegate {

@IBOutlet weak var scrollView: UIScrollView!

// outlet declartion
@IBOutlet weak var signInTextView: UITextField!

var kbHeight: CGFloat!

/**
*
* @method viewDidLoad
*
*/

override func viewDidLoad() {
    super.viewDidLoad()

    self.signInTextView.delegate = self

}// end viewDidLoad

/**
*
* @method viewWillAppear
*
*/

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)

    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)

}// end viewWillAppear

/**
*
* @method viewDidAppear
*
*/

override func viewDidAppear(animated: Bool) {
    super.viewDidAppear(animated)


}// end viewDidAppear

/**
*
* @method viewWillDisappear
*
*/
override func viewWillDisappear(animated: Bool) {
    super.viewWillDisappear(animated)
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

/**
*
* @method textFieldShouldReturn
* retun the keyboard value
*
*/

// MARK -
func textFieldShouldReturn(textField: UITextField) -> Bool {
    signInTextView.resignFirstResponder()
    return true;

}// end textFieldShouldReturn

// MARK - keyboardWillShow
func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        if let keyboardSize =  (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
            kbHeight = keyboardSize.height
            self.animateTextField(true)
        }
    }
}// end keyboardWillShow

// MARK - keyboardWillHide
func keyboardWillHide(notification: NSNotification) {
    self.animateTextField(false)
}// end keyboardWillHide

// MARK - animateTextField
func animateTextField(up: Bool) {
    var movement = (up ? -kbHeight : kbHeight)

    UIView.animateWithDuration(0.3, animations: {
        self.view.frame = CGRectOffset(self.view.frame, 0, movement)
    })
}// end animateTextField

/**
*
* @method didReceiveMemoryWarning
*
*/

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.

}// end didReceiveMemoryWarning


}// end SignInController