应用程序崩溃：异常-无法识别的选择器发送到实例

Question

我有一个UITableviewController，它具有以下逻辑，一旦键盘像这样切换，就可以上下滑动整个视图：

class ChatDetailViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
 // variables...

 override func viewDidLoad() {
        super.viewDidLoad()
        // do stuff...
        NotificationCenter.default.addObserver(self, selector: Selector(("keyboardWillShow:")), name: UIResponder.keyboardWillShowNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: Selector(("keyboardWillHide:")), name: UIResponder.keyboardWillHideNotification, object: nil)
       // do other stuff...
}
...
func keyboardWillShow(notification: NSNotification) {
        if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            self.view.frame.origin.y -= keyboardSize.height
        }
    }

    func keyboardWillHide(notification: NSNotification) {
        self.view.frame.origin.y = 0
    }
...
}

切换键盘，然后使应用程序崩溃，但以下异常：ChatDetailViewController keyboardWillShow：]：无法识别的选择器已发送到实例0x7f82fc41fdf0

乍看起来，错误消息似乎很清楚，但是我仍然无法弄清楚选择器出了什么问题。没有代码警告，没有错别字，...

我在这里做错什么了？

Answer 1

override func viewDidLoad() {
    super.viewDidLoad()   
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: UIResponder.keyboardWillHideNotification, object: nil)
}

u忘记添加@objc部分

Answer 2

三个问题：

Answer 3