如何使用字符串中的参数创建选择器

Question

我正在使用 Swift 3.1 和 Xcode 8.3.3 编写程序。我想创建一个类，负责在键盘出现和消失时移动整个视图。但是我在使用字符串参数创建自定义选择器时遇到了困难。要显示或隐藏键盘，我们需要函数：

func keyboardWillShow(notification: Notification) {
//Code moving view when keyboard appears
}

我正在尝试创建这样的选择器：

let selector = Selector(("keyboardWillShow")
NotificationCenter.default.addObserver(view, selector: selector, name: .UIKeyboardWillShow, object: anyView.view.window)

它正在编译，但是当键盘出现时，它崩溃了。 因为它是独立类，所以我不能使用这种结构：

#selector(keyboardWillShow)

因为它将 Swift 函数转换为 Objective-C 函数（添加 @objc）。 那么问题来了：如何创建带参数字符串的 Selector 表单？

P。 S. 我可以把整个代码放在那里，但我不希望问题很大，所以如果有人问我会编辑问题...

Answer 1

这就是你想要的，带有字符串类型和通知参数参数的选择器

斯威夫特 4

NotificationCenter.default.addObserver(self, selector: Selector(("showKeyboard:")), name:NSNotification.Name.UIKeyboardWillShow, object: nil)

var keyboardHeight = 0.0
//-------------------
@objc func showKeyboard(_ sender: Notification) {
    keyboardWillShow(sender: sender as NSNotification, adjustHeight: 150)
    print("sender - \(sender)")
}

//-------------------
func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
    if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        keyboardHeight = Double(keyboardSize.height)
        // do your calculations
    }
}

斯威夫特 3

NotificationCenter.default.addObserver(view, selector: Selector(("keyboardWillShow:")), name: .UIKeyboardWillShow, object: anyView.view.window)

func keyboardWillShow(_ notification: Notification) { 
       keyboardWillShow(sender: sender as NSNotification, adjustHeight: 150)
        print("sender - \(sender)")

} 

这是正常的选择器，根据语言支持
Swift 4

NotificationCenter.default.addObserver(self, selector: #selector(self.showKeyboard(sender:)), name:NSNotification.Name.UIKeyboardWillShow, object: nil)

var keyboardHeight = 0.0

    //-------------------
    @objc func showKeyboard(sender: NSNotification) {
        keyboardWillShow(sender: sender, adjustHeight: 150)
    }

    //-------------------
    func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
        if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            keyboardHeight = Double(keyboardSize.height)
            // your operations here
        }
    }

斯威夫特 3

NotificationCenter.default.addObserver(self, selector: #selector(self.showKeyboard(sender:)), name:NSNotification.Name.UIKeyboardWillShow, object: nil)

var keyboardHeight = 0.0

    //-------------------
    func showKeyboard(sender: NSNotification) {
        keyboardWillShow(sender: sender, adjustHeight: 150)
    }

   //-------------------
    func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
        if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            keyboardHeight = Double(keyboardSize.height)
            // your operations here
        }
    }

Answer 2

这种方法有效，

override func viewDidLoad() {
    super.viewDidLoad()
// put it wherever you want
 NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(showKeyboard), name:UIKeyboardWillShowNotification, object: nil)
}

func showKeyboard(sender: NSNotification) {
    keyboardWillShow(sender, adjustHeight: 150)
}

func keyboardWillShow(sender: NSNotification, adjustHeight: CGFloat) {
    if let keyboardSize = (sender.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() {
        keyboardHeight = keyboardSize.height
 // do your calculations
    }
}

这将帮助您实现预期的结果。