我使用Swift与iOS编程,我使用这段代码来移动UITextField,但它不起作用。我正确地调用了函数keyboardWillShow,但是文本字段没有移动。我正在使用自动布局。

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);
}

deinit {
    NSNotificationCenter.defaultCenter().removeObserver(self);
}

func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        //let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)

        var frame = self.ChatField.frame
        frame.origin.y = frame.origin.y - keyboardSize.height + 167
        self.chatField.frame = frame
        println("asdasd")
    }
}

当前回答

斯威夫特4。x答案,合并来自@Joseph Lord和@Isuru的答案。bottomConstraint表示你想移动的视图的底部约束。

override func viewDidLoad() {
    // Call super
    super.viewDidLoad()

    // Subscribe to keyboard notifications
    NotificationCenter.default.addObserver(self,
                                           selector: #selector(keyboardNotification(notification:)),
                                           name: UIResponder.keyboardWillChangeFrameNotification,
                                           object: nil)        
}


deinit {
    NotificationCenter.default.removeObserver(self)
}


@objc func keyboardNotification(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        // Get keyboard frame
        let keyboardFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

        // Set new bottom constraint constant
        let bottomConstraintConstant = keyboardFrame.origin.y >= UIScreen.main.bounds.size.height ? 0.0 : keyboardFrame.size.height

        // Set animation properties
        let duration = (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(rawValue: animationCurveRaw)

        // Animate the view you care about
        UIView.animate(withDuration: duration, delay: 0, options: animationCurve, animations: {
            self.bottomConstraint.constant = bottomConstraintConstant
            self.view.layoutIfNeeded()
        }, completion: nil)
    }
}

其他回答

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。

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

最简单的不需要任何代码的方法:

下载KeyboardLayoutConstraint.swift并将文件添加(拖放)到你的项目中,如果你还没有使用Spring动画框架的话。 在你的故事板中,为对象/视图/文本字段创建一个底部约束,选择约束(双击它)并在标识检查器中,将其类从NSLayoutConstraint更改为KeyboardLayoutConstraint。 完成了!

物体会随着键盘同步自动移动。

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)
    }
}

如果视图上有多个文本字段,那么我建议您查看这个方法。当在字段之间切换时,你不会有视图跑开的问题,它会简单地适应所需的文本字段。它在swift 5中工作

  override func viewDidLoad() {
    super.viewDidLoad()
    registerForKeyboardNotification()
}

扩展中的所有方法

extension StartViewController: UITextFieldDelegate {

func registerForKeyboardNotification() {
    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) 
}

@objc func keyboardWillShow(sender: NSNotification) {
    guard let userInfo = sender.userInfo,
          let keyboardFrame = userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue,
          let currentTextField = UIResponder.currentFirst() as? UITextField  else { return }
         
    let keyboardTopY = keyboardFrame.cgRectValue.origin.y
    let convertedTextFieldFrame = view.convert(currentTextField.frame, from: currentTextField.superview)
    let textFieldBottomY = convertedTextFieldFrame.origin.y + convertedTextFieldFrame.size.height
    
    if textFieldBottomY > keyboardTopY {
        let textBoxY = convertedTextFieldFrame.origin.y
        let newFrameY = (textBoxY - keyboardTopY / 2) * -1
        view.frame.origin.y = newFrameY
    }
}


@objc func keyboardWillHide(sender: NSNotification) {
     self.view.frame.origin.y = 0
}


func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    switch textField {
    case emailTextField :
        passwordTextField.becomeFirstResponder()
    default:
        emailTextField.becomeFirstResponder()  
    }
    return true
}

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

最后我们用UIResponder建立方法

extension UIResponder {
private struct Static {
    static weak var responder: UIResponder?
}

static func currentFirst() -> UIResponder? {
    Static.responder = nil
    UIApplication.shared.sendAction(#selector(UIResponder._trap), to: nil, from: nil, for: nil)
    return Static.responder
}

@objc private func _trap() {
    Static.responder = self
}
}