键盘弹出时如何向上移动整个视图？ （迅速）

Question

底部的灰色框是文本视图。当我点击文本视图时，键盘将从底部弹出。但是，文本视图已被弹出键盘覆盖。

我应该添加哪些功能才能在键盘弹出时向上移动整个视图？

Answer 1

要检测键盘何时出现，您可以收听NSNotificationCenter

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

这将调用keyboardWillShow 和keyboardWillHide。在这里你可以用你的UITextfield做你想做的事

func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        if let keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
            //use keyboardSize.height to determine the height of the keyboard and set the height of your textfield accordingly
        }
    }
}

func keyboardWillHide(notification: NSNotification) {
    //pull everything down again
}

Answer 2

正如 Milo 所说，要自己执行此操作，您需要注册键盘显示/隐藏通知。

然后，您需要编写代码来确定键盘隐藏了多少屏幕，以及相关字段在屏幕上的高度，这样您就知道要改变多少视图。

完成此操作后，您要执行的操作取决于您是使用 AutoLayout 还是自动调整大小的遮罩（也称为“Struts and springs”样式布局。）

我写了一篇关于一个项目的开发者博客文章，其中包含用于移动键盘的工作代码。看这个链接：

http://wareto.com/animating-shapes-using-cashapelayer-and-cabasicanimation

在该帖子中，查找底部标题为“滑动视图为键盘腾出空间”的链接。

Answer 3

Swift 4 完整解决方案。

我在所有需要它的项目中都使用它。

在 viewWillAppear 上注册以侦听键盘显示/隐藏，并使用以下功能上下移动视图。

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

    subscribeToKeyboardNotifications()
}

// stop listening for changes when view is dissappearing
override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    unsubscribeFromKeyboardNotifications()
}

// listen for keyboard show/show events
func subscribeToKeyboardNotifications() {
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow(_:)), name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide(_:)), name: .UIKeyboardWillHide, object: nil)
}

func unsubscribeFromKeyboardNotifications() {
    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: .UIKeyboardWillHide, object: nil)
}

@objc func keyboardWillHide(_ notification: Notification) {
    view.frame.origin.y = 0
}

在我的情况下，我在底部有一个文本字段，它被键盘隐藏，所以如果正在使用它，那么我将视图向上移动

@objc func keyboardWillShow(_ notification: Notification) {
    if bottomTextField.isFirstResponder {
        view.frame.origin.y = -getKeyboardHeight(notification: notification)
    }
}

func getKeyboardHeight(notification: Notification) -> CGFloat {
    let userInfo = notification.userInfo
    let keyboardSize = userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue
    return keyboardSize.cgRectValue.height
}

Answer 4

斯威夫特 4

这段代码不是那么完美，但值得一试！

首先将整个视图嵌入到一个滚动视图中。

将这个可爱的小函数添加到你的类中：

@objc func keyboardNotification(_ notification: Notification) {
    if let userInfo = (notification as NSNotification).userInfo {
        let endFrame = (userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
        let duration:TimeInterval = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0
        let animationCurveRawNSN = userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber
        let animationCurveRaw = animationCurveRawNSN?.uintValue ?? UIViewAnimationOptions().rawValue
        let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
        if (endFrame?.origin.y)! >= UIScreen.main.bounds.size.height {
            scrollViewBottomConstraint?.constant = 0
        } else {
            if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
                let keyboardHeight:Int = Int(keyboardSize.height)
                scrollViewBottomConstraint?.constant = CGFloat(keyboardHeight)
                scrollView.setContentOffset(CGPoint(x: 0, y: (scrollViewBottomConstraint?.constant)! / 2), animated: true)
            }
        }
        UIView.animate(withDuration: duration, delay: TimeInterval(0), options: animationCurve, animations: {
            self.view.layoutIfNeeded()
        }, completion: nil)
    }
}

.

将此添加到您的 ViewDidLoad：

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

不要忘记将滚动视图的底部约束连接到您的类（名称：“scrollViewBottomConstraint”）。