Question

我似乎找不到我做的功能。

错误：类型'ChatViewController'没有成员'showOrHideKeyboard'

代码：

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    NotificationCenter.defaultCenter.addObserver(self, selector: #selector(ChatViewController.showOrHideKeyboard(_:)), name: UIKeyboardWillShowNotification, object: nil)
    NotificationCenter.defaultCenter.addObserver(self, selector: #selector(ChatViewController.showOrHideKeyboard(_:)), name: UIKeyboardWillHideNotification, object: nil)
}

@IBOutlet weak var contraintToBottom: NSLayoutConstraint!

func showOrHideKeyboard(notification: NSNotification) {
    if let keyboardInfo: Dictionary = notification.userInfo {
        if notification.name == UIResponder.keyboardWillShowNotification {
            UIView.animate(withDuration: 1, animations: { () in
                self.contraintToBottom.constant = (keyboardInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue.height
                self.view.layoutIfNeeded()
            }) { (completed: Bool) -> Void in
                //
            }
        }
    }
}

Answer 1

您应将选择器方法标记为objc

更改此行

func showOrHideKeyboard(notification: NSNotification) {
}

此行

@objc func showOrHideKeyboard(_ notification: NSNotification) {
}

Answer 2

使用以下任一方法：

@objc func showOrHideKeyboard(_ notification: NSNotification) 
#selector(ChatViewController.showOrHideKeyboard(_:))

或者：

@objc func showOrHideKeyboard(notification: NSNotification) {
#selector(ChatViewController.showOrHideKeyboard(notification:))

请注意函数签名中的_和#selector。

Answer 3

在最新版本的快速版本中，似乎不再支持带有函数名称但不带参数名称“（_ :)”的#selector。

只需替换填充arg名称或使用自动完成功能即可键入声明：

#selector(ViewController.showOrHideKeyboard(notification:)

Answer 4

按如下所示优化代码

在ViewDidLoad（）

[NSNotification.Name.UIKeyboardWillShow,
         NSNotification.Name.UIKeyboardWillHide].forEach { (notificationName) in
            NotificationCenter.default.addObserver(self, selector: #selector(notificationObservered(notification:)),
                                                   name: notificationName, object: nil)
        }

创建函数

// MARK: - Notification Observered
    /// Notification received
    @objc func notificationObservered(notification: NSNotification) {

        switch notification.name {
        case NSNotification.Name.UIKeyboardWillShow:
            break
        case NSNotification.Name.UIKeyboardWillHide:
            // let info = notification.userInfo!
            // let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
           break
        default:
            break
        }
    }

类型“ ChatViewController”没有成员“ showOrHideKeyboard”

4 个答案: