隐藏键盘Swift 4后视图底部的元素消失答案

【问题标题】：Element at the bottom of view disappear after hiding the keyboard Swift 4隐藏键盘Swift 4后视图底部的元素消失
【发布时间】：2018-01-20 16:55:32
【问题描述】：

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，键盘是隐藏的但屏幕底部的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？又该如何解决？？

【问题讨论】：

使用 UIKeyboardFrameEndUserInfoKey 代替 UIKeyboardFrameBeginUserInfoKey。
@ArunGJ 是有效的..谢谢..你可以回答一下，所以我可以接受吗？？

标签： ios keyboard swift4

【解决方案1】：

使用UIKeyboardFrameEndUserInfoKey 代替UIKeyboardFrameBeginUserInfoKey 因为UIKeyboardFrameBeginUserInfoKey 可以在keyboardWillShow 和keyboardWillHide 中返回不同的值

UIKeyboardFrameBeginUserInfoKey – 当前键盘状态变化开始时的键盘框架。 UIKeyboardFrameEndUserInfoKey – 当前键盘状态更改结束时的键盘框架。

【讨论】：