键盘停止显示UIToolbar

我的视图上有一个UITextView，可以通过在键盘工具栏上按一个do按钮来取消键盘。此按钮还在对文本执行保存。在我的应用程序的最新版本之前，整个过程都是完美的。我不知道发生了什么。我怀疑问题在于设置我的应用程序与iOS 11.0版本的向后兼容性。但后来我又尝试了更高的开发目标，结果是一样的。在构建最近的更新时，我没有接触到这个视图的代码，所以我不确定是什么导致了这个问题。我代码的相关部分：

let textView: UITextView = {
    let tw = UITextView()
    tw.font = Font.kohinoorTeluguMedium_20
    tw.returnKeyType = .default
    tw.isScrollEnabled = true
    tw.keyboardDismissMode = .interactive
    tw.translatesAutoresizingMaskIntoConstraints = false
    return tw
  }()


fileprivate func setupKeyboardToolbar() {
    let keyboardToolBar = UIToolbar(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
      keyboardToolBar.translatesAutoresizingMaskIntoConstraints = false
        keyboardToolBar.sizeToFit()

        let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(handleDoneButton))
    keyboardToolBar.items = [doneButton]
    self.textView.inputAccessoryView = keyboardToolBar
       textView.delegate = self  
//        self.textView.autoresizingMask = .flexibleHeight
    keyboardToolBar.layoutIfNeeded()
    keyboardToolBar.isHidden = false
}

override func viewDidLoad() {
    super.viewDidLoad()

    setupKeyboardToolbar()

    tableView.register(DetailCell.self, forCellReuseIdentifier: cellId)
    tableView.backgroundColor = AdaptiveColors.tableViewBackgroundColor
    tableView.separatorColor = AdaptiveColors.tableViewBackgroundColor
    setupDismissButton()

    let editButton = UIBarButtonItem(title: LocalizedString.edit, style: .plain, target: self, action: #selector(handleEdit))
    editButton.tintColor = .white
    navigationItem.rightBarButtonItem = editButton

}
 @objc func handleDoneButton() {
    let context = CoreDataManager.shared.persistentContainer.viewContext
    lesson?.notes = textView.text
    do {
        try context.save()
    } catch let savErr {
        print("Error saving context \(savErr)")
    }
    textView.resignFirstResponder()
}

func textViewDidChange(_ textView: UITextView) {
    tableView.beginUpdates()
    tableView.endUpdates()
}

func textViewShouldBeginEditing(_ textView: UITextView) -> Bool {
return true
}
}

在阅读了相关的StackOverflow答案之后，我尝试过调用layoutIfNeeded()和isHidden = false在……上面keyboardToolbar没有运气。也试着self.textView.autoResizingMask = .flexibleHeight没有运气。也试图keyboardToolbar的代表self，宣布自己为UIToolbarDelegate...谢谢大家的帮助！