NSNotification.Name.UIKeyboardWillShow崩溃 – 无法找到原因

我的应用程序的用户报告了随机崩溃。 我已经集成了CrashAnalytics，它提供了以下详细信息：

__CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20. 

显示的行号为154，即：

 self.notesView.content.frame = CGRect(x: self.notesView.content.frame.origin.x, y: self.notesView.content.frame.origin.y, width: self.notesView.content.frame.size.width, height: self.notesView.content.frame.size.height - keyboardFrame.size.height). 

以下是我写的代码，包括这一行：

 override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) label_title.addObserver(self, forKeyPath: "contentSize", options: .new, context: nil) NotificationCenter.default.addObserver(self, selector: #selector(keyboardShown), name:NSNotification.Name.UIKeyboardWillShow, object: nil); NotificationCenter.default.addObserver(self, selector: #selector(keyboardHide), name:NSNotification.Name.UIKeyboardWillHide, object: nil); } override func viewWillDisappear(_ animated: Bool) { super.viewWillDisappear(animated) label_title.removeObserver(self, forKeyPath: "contentSize") NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil) NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil) } func keyboardShown(notification: NSNotification) { let info = notification.userInfo! let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue self.notesView.content.frame = CGRect(x: self.notesView.content.frame.origin.x, y: self.notesView.content.frame.origin.y, width: self.notesView.content.frame.size.width, height: self.notesView.content.frame.size.height - keyboardFrame.size.height) } 

首先，这是随机的，我从来没有得到它。 其次，我无法找到确切的原因。 这是因为通知观察者还是因为notesView（不是nil）。
正如这里建议的那样，我应该删除deinit中的键盘通知观察者吗？
如果有人以前经历过这个，请指导我。

Answer 1

将function的签名更改为此

 @objc func keyboardShown(_ notification: Notification)