ios - 键盘动画延迟

Question

我试图在键盘显示和隐藏时移动 ScrollView 内容。我正在做基本功能。但键盘先可见，向上移动动画有延迟，更新到ios 11后延迟更大。

代码:

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

@objc func keyboardNotification(notification: NSNotification) {


        if let userInfo = notification.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.curveEaseInOut.rawValue
            let animationCurve:UIViewAnimationOptions = UIViewAnimationOptions(rawValue: animationCurveRaw)
            if (endFrame?.origin.y)! >= 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)
        }
    }

keyboardHeightLayoutConstraint是scrollview的底部约束。

我做错了什么？任何帮助，将不胜感激。谢谢!

Answer 1

您尝试给出 ScrollView 的高度并使用主视图高度进行计算 - 键盘高度和键盘更改框架将工作延迟，如果您想捕获键盘打开和隐藏，您应该将它们添加到 viewdidload 上:

全局:var KeyboardHeight:CGFloat？

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)

加载时计算 ScrollView 高度

self.scrollviewHeight.constant = self.view.frame.height - keyboardHeight - self.textView.frame.height

你可以用UIView.animation这样计算