出现键盘时无法上移自定义 UIView答案

【问题标题】：Cannot move up custom UIView when keyboard appears出现键盘时无法上移自定义 UIView
【发布时间】：2020-05-19 21:41:21
【问题描述】：

我在移动自定义 UIView（基本上是一个警报）时遇到了一些问题。当我打开键盘时，一切正常，并且警报按原样向上移动。但是，只要我在 textField 中输入某些内容，警报就会回到原来的位置。我不知道为什么会这样。顺便说一句，警报视图被添加到情节提要中并被限制在中心。我附上了一些解释性的图片提前致谢。

class AlertViewController: UIViewController {
       @IBOutlet var AlertView: UIView! //Alert View storyboard outlet

       override func viewDidLoad() { 
        NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: 
        UIResponder.keyboardWillShowNotification, object: nil)
 }

@objc func keyboardWillShow(notification: NSNotification){

        guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
           // if keyboard size is not available for some reason, don't do anything
           return
        }

        let keyBoardTop = self.view.frame.height - keyboardSize.height
        let bottomOfAlertView = AlertView.convert(AlertView.bounds, to: self.view).maxY;

        print("keyBoardTop: \(keyBoardTop)")
        print("BottomOfAlertView: \(bottomOfAlertView)")
        print(AlertView.frame.origin.y)

        AlertView.frame.origin.y = AlertView.frame.origin.y - (bottomOfAlertView - keyBoardTop)

    }
}

Img Correct

Img Alert after typing

【问题讨论】：

标签： ios swift uiview

【解决方案1】：

尝试像这样更改警报的底部约束怎么样

@objc func handleShowKeyboard(_ notification: Notification) {
    if let keyboardFrame: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue {
        let keyboardRectangle = keyboardFrame.cgRectValue
        let keyboardOffset = keyboardRectangle.height
        if AlertView.viewBottomAnchor.constant == 0 {
            AlertView.viewBottomAnchor.constant -= (keyboardOffset - self.view.safeAreaInsets.bottom)
            AlertView.layoutIfNeeded()
        }
    }
}

【讨论】：