NSNotfication.addObserver - 更新到当前的 Swift 语法？

Question

目前正在学习教程，但是，某些语法已过时。基本上代码应该显示和隐藏用户键盘。我在使用 addObserver 方法时遇到一些语法错误，并且 Swift 希望我改用键路径，但是，如果我使用自动 'fix-it' 我会收到更多错误。谁能帮我解决这个问题？谢谢！

NSNotification.addObserver(self, selector: #selector(keyboardwillShow), name: .UIKeyboardWillShow, nil)       
NSNotification.addObserver(self, selector: #selector(keyboardwillHide), name: .UIKeyboardWillHide, nil)


func keyboardwillShow(_notification:NSNotification) {    
    keyboard = (_notification.userInfo![UIKeyboardFrameEndUserInfoKey]! as AnyObject).cgRectValue
    UIView.animate(withDuration: 0.4) { 
        self.scrolledView.frame.size.height = self.scrollViewHeight - self.keyboard.height
    }
}

func keyboardwillHide(_notification:NSNotification) {
    UIView.animate(withDuration: 0.5) { 
        self.scrolledView.frame.size.height = self.view.frame.height
    }
}

我收到调试消息："Incorrect argument labels in call(have _selector:name, expected _forKeyPath:options:context"

Answer 1

你的函数有参数，当你在观察者中添加它时缺少参数

而且你必须使用 NotificationCenter.default.addObserver 而不是 NotificationCenter.addObserver

let selectorForKeyBoardWillShow: Selector = #selector(ViewController.keyboardWillShow(_:))
let selectorForKeyBoardWillHide: Selector = #selector(ViewController.keyboardWillHide(_:))

    // MARK: - Functions
override func viewDidLoad() {
    super.viewDidLoad()
    NotificationCenter.default.addObserver(self, selector: selectorForKeyBoardWillShow, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.addObserver(self, selector: selectorForKeyBoardWillHide, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}


// MARK: Keyboard Observer
func keyboardWillShow(_ notification: Notification) {
}

func keyboardWillHide(_ notification: Notification) {
}

NSNotfication.addObserver - 更新到当前的 Swift 语法？

NSNotfication.addObserver - Update to current Swift Syntax?

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