ios - 隐藏键盘 Swift 4 后 View 底部的元素消失

Question

我的屏幕底部有 2 个按钮。我实现了下面的代码以显示和隐藏键盘，但不覆盖底部的 2 个按钮。

override func viewDidLoad() {
        super.viewDidLoad()

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

    //here will hide the keyboard when tap the text view 2 times
    let tap = UITapGestureRecognizer(target: self, action: #selector(hideKeyBoard))
    self.statusTextView.addGestureRecognizer(tap)
}

@objc func hideKeyBoard(sender: UITapGestureRecognizer? = nil){
        statusTextView.endEditing(true)
 }

@objc func keyboardWillShow(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {

            if let window = self.view.window?.frame {
                // We're not just minusing the kb height from the view height because
                // the view could already have been resized for the keyboard before
                self.view.frame = CGRect(x: self.view.frame.origin.x,
                                         y: self.view.frame.origin.y,
                                         width: self.view.frame.width,
                                         height: window.origin.y + window.height - keyboardSize.height)
            }

        }
    }

    @objc func keyboardWillHide(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {

            let viewHeight = self.view.frame.height
            self.view.frame = CGRect(x: self.view.frame.origin.x,
                                     y: self.view.frame.origin.y,
                                     width: self.view.frame.width,
                                     height: viewHeight + keyboardSize.height)
        }
    }

通过上面的代码，我成功地显示和隐藏了键盘，没有覆盖底部的任何元素。

但是奇怪的事情发生了，当我点击 textview 2 次时，键盘隐藏了但是屏幕底部的 2 按钮消失了。

所以我的问题是，为什么隐藏键盘时元素会消失？以及如何解决？？

Answer 1

使用 UIKeyboardFrameEndUserInfoKey 而不是 UIKeyboardFrameBeginUserInfoKey 因为 UIKeyboardFrameBeginUserInfoKey 可以在 keyboardWillShow 和 keyboardWillHide< 中返回不同的值

UIKeyboardFrameBeginUserInfoKey – 当前键盘状态改变开始时的键盘框架。 UIKeyboardFrameEndUserInfoKey – 当前键盘状态更改结束时的键盘框架。