func registerForKeyboardNotifications(){
        //Keyboard
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWasShown), name: UIKeyboardDidShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillBeHidden), name: UIKeyboardDidHideNotification, object: nil)


    }
    func deregisterFromKeyboardNotifications(){

        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)

    }
    func keyboardWasShown(notification: NSNotification){

        let userInfo: NSDictionary = notification.userInfo!
        let keyboardInfoFrame = userInfo.objectForKey(UIKeyboardFrameEndUserInfoKey)?.CGRectValue()

        let windowFrame:CGRect = (UIApplication.sharedApplication().keyWindow!.convertRect(self.view.frame, fromView:self.view))

        let keyboardFrame = CGRectIntersection(windowFrame, keyboardInfoFrame!)

        let coveredFrame = UIApplication.sharedApplication().keyWindow!.convertRect(keyboardFrame, toView:self.view)

        let contentInsets = UIEdgeInsetsMake(0, 0, (coveredFrame.size.height), 0.0)
        self.scrollViewInAddCase .contentInset = contentInsets;
        self.scrollViewInAddCase.scrollIndicatorInsets = contentInsets;
        self.scrollViewInAddCase.contentSize = CGSizeMake((self.scrollViewInAddCase.contentSize.width), (self.scrollViewInAddCase.contentSize.height))

    }
    /**
     this method will fire when keyboard was hidden

     - parameter notification: contains keyboard details
     */
    func keyboardWillBeHidden (notification: NSNotification) {

        self.scrollViewInAddCase.contentInset = UIEdgeInsetsZero
        self.scrollViewInAddCase.scrollIndicatorInsets = UIEdgeInsetsZero

    }

我使用的Swift 4解决方案需要键盘大小。将serverStatusStackView替换为任何你关心的视图，例如:self.view:

deinit {
    NotificationCenter.default.removeObserver(self)
}

@objc func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        serverStatusStackView.frame.origin.y = keyboardSize.height * 2 - serverStatusStackView.frame.height
    }
}

@objc func keyboardWillHide(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        serverStatusStackView.frame.origin.y += keyboardSize.height
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

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

对于任何不使用故事板设置布局约束的人。这是一种纯粹的编程方式，让它在Swift 5上工作:

在viewController中定义一个空约束。在这种情况下，我正在构建一个聊天应用程序，在屏幕的最底部有一个包含文本视图的UIView。

var discussionsMessageBoxBottomAnchor: NSLayoutConstraint = NSLayoutConstraint()

在viewDidLoad中为最底部的视图添加约束。在本例中是discussionsMessageBox。另外，为键盘事件添加监听器。

为了正确地初始化约束，您需要首先添加子视图，然后定义约束。

NotificationCenter.default.addObserver(self,
                                       selector: #selector(self.keyboardNotification(notification:)),
                                       name: NSNotification.Name.UIKeyboardWillChangeFrame,
                                       object: nil)

view.addSubview(discussionsMessageBox)

if #available(iOS 11.0, *) {
    discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0)
} else {
    // Fallback on earlier versions
    discussionsMessageBoxBottomAnchor = discussionsMessageBox.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 0)
}

NSLayoutConstraint.activate([ discussionsMessageBoxBottomAnchor ])

定义deinit。

deinit {
        NotificationCenter.default.removeObserver(self)
    }

接下来添加@JosephLord定义的代码，并对偏移量进行修正。

extension DiscussionsViewController {
    @objc func keyboardNotification(notification: NSNotification) {
        guard let userInfo = notification.userInfo else { return }
        
        let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
        let endFrameY = endFrame?.origin.y ?? 0
        let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] 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.discussionsMessageBoxBottomAnchor.constant = 0.0
        } else {
            //Changed line
            self.discussionsMessageBoxBottomAnchor.constant = -1 * (endFrame?.size.height ?? 0.0)
        }
        
        UIView.animate(
            withDuration: duration,
            delay: TimeInterval(0),
            options: animationCurve,
            animations: { self.view.layoutIfNeeded() },
            completion: nil)
    }
}

struct MoveKeyboard {
    static let KEYBOARD_ANIMATION_DURATION : CGFloat = 0.3
    static let MINIMUM_SCROLL_FRACTION : CGFloat = 0.2;
    static let MAXIMUM_SCROLL_FRACTION : CGFloat = 0.8;
    static let PORTRAIT_KEYBOARD_HEIGHT : CGFloat = 216;
    static let LANDSCAPE_KEYBOARD_HEIGHT : CGFloat = 162;
}


  func textFieldDidBeginEditing(textField: UITextField) {
    let textFieldRect : CGRect = self.view.window!.convertRect(textField.bounds, fromView: textField)
    let viewRect : CGRect = self.view.window!.convertRect(self.view.bounds, fromView: self.view)

    let midline : CGFloat = textFieldRect.origin.y + 0.5 * textFieldRect.size.height
    let numerator : CGFloat = midline - viewRect.origin.y - MoveKeyboard.MINIMUM_SCROLL_FRACTION * viewRect.size.height
    let denominator : CGFloat = (MoveKeyboard.MAXIMUM_SCROLL_FRACTION - MoveKeyboard.MINIMUM_SCROLL_FRACTION) * viewRect.size.height
    var heightFraction : CGFloat = numerator / denominator

    if heightFraction < 0.0 {
        heightFraction = 0.0
    } else if heightFraction > 1.0 {
        heightFraction = 1.0
    }

    let orientation : UIInterfaceOrientation = UIApplication.sharedApplication().statusBarOrientation
    if (orientation == UIInterfaceOrientation.Portrait || orientation == UIInterfaceOrientation.PortraitUpsideDown) {
        animateDistance = floor(MoveKeyboard.PORTRAIT_KEYBOARD_HEIGHT * heightFraction)
    } else {
        animateDistance = floor(MoveKeyboard.LANDSCAPE_KEYBOARD_HEIGHT * heightFraction)
    }

    var viewFrame : CGRect = self.view.frame
    viewFrame.origin.y -= animateDistance

    UIView.beginAnimations(nil, context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)
    UIView.setAnimationDuration(NSTimeInterval(MoveKeyboard.KEYBOARD_ANIMATION_DURATION))

    self.view.frame = viewFrame

    UIView.commitAnimations()
}


func textFieldDidEndEditing(textField: UITextField) {
    var viewFrame : CGRect = self.view.frame
    viewFrame.origin.y += animateDistance

    UIView.beginAnimations(nil, context: nil)
    UIView.setAnimationBeginsFromCurrentState(true)

    UIView.setAnimationDuration(NSTimeInterval(MoveKeyboard.KEYBOARD_ANIMATION_DURATION))

    self.view.frame = viewFrame

    UIView.commitAnimations()

}

最后，因为我们使用委托方法

func textFieldShouldReturn(textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }

使用objective-c重构http://www.cocoawithlove.com/2008/10/sliding-uitextfields-around-to-avoid.html

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
    }
}

一个简单的解决方案是移动视图与键盘高度常数。

override func viewDidLoad() {
   super.viewDidLoad()        
   NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name:UIKeyboardWillShowNotification, object: nil);
   NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name:UIKeyboardWillHideNotification, object: nil);
}

@objc func keyboardWillShow(sender: NSNotification) {
     self.view.frame.origin.y = -150 // Move view 150 points upward 
}

@objc func keyboardWillHide(sender: NSNotification) {
     self.view.frame.origin.y = 0 // Move view to original position  
}

斯威夫特5:

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(sender:)), name: UIResponder.keyboardWillShowNotification, object: nil);

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(sender:)), name: UIResponder.keyboardWillHideNotification, object: nil);