在现有的答案上有一些改进。

首先，uikeyboardwillchangeframeotification可能是最好的通知，因为它处理的变化不仅仅是显示/隐藏，而是由于键盘变化(语言，使用第三方键盘等)和旋转(但注意下面的评论表明键盘将隐藏也应该处理以支持硬件键盘连接)。

其次，动画参数可以从通知中提取，以确保动画正确地组合在一起。

可能有一些选项可以进一步清理此代码，特别是如果您对强制展开字典代码感到满意的话。

 class MyViewController: UIViewController {

   // This constraint ties an element at zero points from the bottom layout guide
   @IBOutlet var keyboardHeightLayoutConstraint: NSLayoutConstraint?
 
   override func viewDidLoad() {
     super.viewDidLoad()
     NotificationCenter.default.addObserver(self,
       selector: #selector(self.keyboardNotification(notification:)),
       name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
   }
 
   deinit {
     NotificationCenter.default.removeObserver(self)
   }
 
   @objc func keyboardNotification(notification: NSNotification) {
     guard let userInfo = notification.userInfo else { return }

     let endFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
     let endFrameY = endFrame?.origin.y ?? 0
     let duration:TimeInterval = (userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
     let animationCurveRawNSN = userInfo[UIResponder.keyboardAnimationCurveUserInfoKey] as? NSNumber
     let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions.curveEaseInOut.rawValue
     let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)

     if endFrameY >= UIScreen.main.bounds.size.height {
       self.keyboardHeightLayoutConstraint?.constant = 0.0
     } else {
       self.keyboardHeightLayoutConstraint?.constant = endFrame?.size.height ?? 0.0
     }

     UIView.animate(
       withDuration: duration,
       delay: TimeInterval(0),
       options: animationCurve,
       animations: { self.view.layoutIfNeeded() },
       completion: nil)
   }
}

我正在使用swift 4，我解决了这个问题，没有使用任何额外的底部约束，看我的代码在这里。这对我的案子很有帮助

1)在did load中添加通知观察者

override func viewDidLoad() { super.viewDidLoad () setupManager () //加载视图后进行任何额外的设置。 addobserver (self, selector: #selector(self. keyboardwillshow)， name: NSNotification.Name。对象:nil) addobserver (self, selector: #selector(self. keyboardwillhide)， name: NSNotification.Name。对象:nil) ｝

2)删除通知观察者

Deinit { NotificationCenter.default.removeObserver（self） }

3)增加键盘显示/隐藏方法

 @objc func keyboardWillShow(notification: NSNotification) {
            if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
                UIView.animate(withDuration: 0.1, animations: { () -> Void in
                    self.view.frame.origin.y -= keyboardSize.height
                    self.view.layoutIfNeeded()
                })
            }
        }

@objc func keyboardWillHide(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            UIView.animate(withDuration: 0.1, animations: { () -> Void in
                self.view.frame.origin.y += keyboardSize.height
                self.view.layoutIfNeeded()
            })
        }
    }

4)添加textfield delegate和touchesBegan方法。usefull用于在屏幕上的textfield外触摸时隐藏键盘

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        view.endEditing(true)

    }

下面是一个简单的解决方案，其中文本字段有一个约束将其绑定到底部布局指南。它只是将键盘高度添加到约束常数中。

// This constraint ties the text field to the bottom layout guide
@IBOutlet var textFieldToBottomLayoutGuideConstraint: NSLayoutConstraint!

override func viewDidLoad() {
    super.viewDidLoad()

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

func keyboardWillShow(sender: NSNotification) {
    if let keyboardSize = (sender.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        self.textFieldToBottomLayoutGuideConstraint?.constant += keyboardSize.height
    }
}

func keyboardWillHide(sender: NSNotification) {
    if let keyboardSize = (sender.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        self.textFieldToBottomLayoutGuideConstraint?.constant -= keyboardSize.height
    }
}

你可以使用这个库，只需一行代码在appDidFinishedLaunching和你完成。

func application(application: UIApplication,didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    IQKeyboardManager.sharedManager().enable = true
    return true
}

IQKeyboardManager -调整视图每当键盘出现 link - https://github.com/hackiftekhar/IQKeyboardManager

在编辑文本框时移动您的视图试试这个，我已经应用了这个，

选项1:—** **在Swift 5.0和iPhone X、XR、XS和XS Max中更新 使用NotificationCenter移动

在func viewWillAppear中注册这个通知(_ animated: Bool) 在func中注销此通知viewWillDisappear(_ animated: Bool)

注意:-如果你不取消注册，那么它将从子类调用，并将导致崩溃或其他。

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    NotificationCenter.default.addObserver( self, selector: #selector(keyboardWillShow(notification:)), name:  UIResponder.keyboardWillShowNotification, object: nil )
}
override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
}

@objc func keyboardWillShow( notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        var newHeight: CGFloat
        let duration:TimeInterval = (notification.userInfo![UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = notification.userInfo![UIResponder.keyboardAnimationCurveUserInfoKey] as? NSNumber
        let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIView.AnimationOptions.curveEaseInOut.rawValue
        let animationCurve:UIView.AnimationOptions = UIView.AnimationOptions(rawValue: animationCurveRaw)
        if #available(iOS 11.0, *) {
            newHeight = keyboardFrame.cgRectValue.height - self.view.safeAreaInsets.bottom
        } else {
            newHeight = keyboardFrame.cgRectValue.height
        }
        let keyboardHeight = newHeight  + 10 // **10 is bottom margin of View**  and **this newHeight will be keyboard height**
        UIView.animate(withDuration: duration,
                       delay: TimeInterval(0),
                       options: animationCurve,
                       animations: {
                        self.view.textViewBottomConstraint.constant = keyboardHeight **//Here you can manage your view constraints for animated show**
                        self.view.layoutIfNeeded() },
                       completion: nil)
    }
}

方案二:- 工作正常

func textFieldDidBeginEditing(textField: UITextField) {
        self.animateViewMoving(up: true, moveValue: 100)
}
func textFieldDidEndEditing(textField: UITextField) {
        self.animateViewMoving(up: false, moveValue: 100)
}

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

当键盘出现在Swift中时，我从这个源UITextField中得到了这个答案

在斯威夫特4——

func textFieldDidBeginEditing(_ textField: UITextField) {
        animateViewMoving(up: true, moveValue: 100)
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        animateViewMoving(up: false, moveValue: 100)
    }
    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()
    }

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。