为什么底视图无法快速显示键盘？

Question

我正在使用键盘通知底视图。

我在情节提要中给出了底视图约束，如下所示：

bottom to safe area = 0, leading, trailing = 0 , height = 80

i phone8效果很好，但是在iphone11中，bottomview与设备底部之间的距离越来越小，所以，如果我将底部约束更改为0到superview，则bottomview不会出现键盘

这里是代码：

class ChatViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var bottomConstraint: NSLayoutConstraint!
    @IBOutlet weak var customView: UIView!

    @IBOutlet weak var msgTextField: UITextField!
    @IBOutlet weak var tableView: UITableView!

    override func viewDidLoad() {
        super.viewDidLoad()


        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: UIResponder.keyboardWillShowNotification, object: nil)

        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardNotification), name: UIResponder.keyboardWillHideNotification, object: nil)
    }

    override func viewWillDisappear(_ animated: Bool) {
        NotificationCenter.default.removeObserver(self)
    }

    @objc func handleKeyboardNotification(_ notification: Notification) {

        if let userInfo = notification.userInfo {

            let keyboardFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as AnyObject).cgRectValue

            let isKeyboardShowing = notification.name == UIResponder.keyboardWillShowNotification

            bottomConstraint?.constant = isKeyboardShowing ? -keyboardFrame!.height : 0

            UIView.animate(withDuration: 0.5, animations: { () -> Void in
                self.view.layoutIfNeeded()
            })
        }
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        self.customView.superview?.setNeedsLayout()
        //self.customView.superview?.layoutIfNeeded()
    }
}

请帮助我。

Answer 1

该问题可能是由于对keyboardWillHide和keyboardWillShow通知使用了相同的选择器。您需要使用以下代码将它们分开：

    override func viewDidLoad() {    
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardDidAppear(notification:)), name: 
        NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardDidDisappear(notification:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }
    @objc func keyboardDidAppear(notification:Notification){
        let info = notification.userInfo
        let value = info![UIKeyboardFrameEndUserInfoKey] as? NSValue

        let rawFrame = value?.cgRectValue
        let keyboardFrame = view.convert(rawFrame!, from: nil)

        bottomConstarint?.constant = keyboardFrame.size.height
        tableView.scrollToBottom()
        UIView.animate(withDuration: 0.5, animations: { () -> Void in
                self.view.layoutIfNeeded()
        })

    }
    @objc func keyboardDidDisappear(notification:Notification){

        bottomConstarint?.constant = 0
        tableView.scrollToBottom()
    }