滚动视图和文本字段无法正确向上滚动视图

Question

出现键盘时，我正在使用滚动视图向上滚动视图。

this is how the controller looks

下一张图片是我第一次激活键盘时控制器的外观。我的问题是大标题消失了。我设置了倾向于在确实加载的视图中将大标题设置为true，并且大标题显示模式始终为=。，但是看起来滚动视图中的视图向上移动，从而使导航栏变小了。

this is how the controller looks when I dismiss the view interactively using the tableview

下一张图片是第二次单击文本字段后发生的情况。文本字段显示在键盘下方，导航栏仍然很小。我需要像第二个图像一样的文本字段，并且我需要导航栏始终较大。

这是我的代码：

class ChatVC: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBOutlet weak var tableView: UITableView!
    @IBOutlet weak var sendMessageView: UIView!
    @IBOutlet var superViewContainer: UIView!

    @IBOutlet weak var scrollView: UIScrollView!



    var Messages = [Message]()

    override func viewDidLoad() {
        super.viewDidLoad()
        self.tableView.delegate = self
        self.tableView.dataSource = self
        self.navigationItem.largeTitleDisplayMode = UINavigationItem.LargeTitleDisplayMode.always
        self.navigationController?.navigationBar.prefersLargeTitles = true
        self.navigationItem.largeTitleDisplayMode = .always

        let m1 = Message(senderName: "Chris", message: "This is my new message, iejiejdijaidnjadnjasndjanjdjdjandjjdnjasnjdsadnsnajdnjasdnjsnkkmdklllll")
        let m2 = Message(senderName: "John ", message: "This is read")

        Messages.append(m1)
        Messages.append(m2)
        Messages.append(m1)
        Messages.append(m2)
        Messages.append(m1)
        Messages.append(m2)
        Messages.append(m1)
        Messages.append(m2)
        Messages.append(m1)
        Messages.append(m2)

        print(Messages)

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

        if #available(iOS 11, *) {
            UIScrollView.appearance().contentInsetAdjustmentBehavior = .never
        }
    }

    override func viewWillDisappear(_ animated: Bool) {
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: self.view.window)
        NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: self.view.window)

    }


    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return Messages.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = self.tableView.dequeueReusableCell(withIdentifier: chatCellId) as! ChatCell

        cell.messageLbl.text = Messages[indexPath.row].message

        return cell
    }



    @objc func keyboardWillShow(notification: NSNotification) {

        var userInfo = notification.userInfo!
        var keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
        keyboardFrame = self.view.convert(keyboardFrame, from: nil)

        var contentInset:UIEdgeInsets = self.scrollView.contentInset
        contentInset.bottom = keyboardFrame.size.height - 20
        scrollView.contentInset = contentInset
    }

    @objc func keyboardWillHide(notification: NSNotification) {
            let contentInset:UIEdgeInsets = UIEdgeInsets.zero
            scrollView.contentInset = contentInset
    }

    func textFieldShouldReturn(textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }}

移动视图的代码是keyboardWillShow（）函数