UIKeyboardWillHideNotification上无法识别的选择器

Question

我正在尝试在我的KeyboardScrollController类中获取键盘通知，但我无法识别选择器UIKeyboardWillHideNotification和UIKeyboardDidShowNotification。

这是我简单的实现：

public class KeyboardScrollController 
{ 
    public func subscribeForKeyboardNotifications() 
    { 
     NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWasShown:", name: UIKeyboardDidShowNotification, object: nil) 
     NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil) 
    } 

    public func unsubscribeForKeyboardNotifications() 
    { 
     NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardDidShowNotification, object: nil); 
     NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil); 
    } 

    //MARK: Keyboard events 
    public func keyboardWasShown(notification: NSNotification) 
    { 

    } 

    public func keyboardWillHide(notification: NSNotification) 
    { 

    } 
} 

但键盘应提交每次都与此错误崩溃：

*** NSForwarding: warning: object 0x7fdc8d882730 of class 'KeyboardScrollController' does not implement methodSignatureForSelector: -- trouble ahead Unrecognized selector -[KeyboardScrollController keyboardWillHide:]

我试图与Selecor("keyboardWillHide:")，但没有作出任何区别。

这里有什么问题？我已经在Objective-C中实现了这几次，但我无法在Swift中使用它。

Answer 1

啊，它突然打到我，这个问题可能是什么。我不得不从NSObject继承，使其工作：

public class KeyboardScrollController : NSObject 
{ 
    public func subscribeForKeyboardNotifications() 
    { 
     NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWasShown:", name: UIKeyboardDidShowNotification, object: nil) 
     NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil) 
    } 

    public func unsubscribeForKeyboardNotifications() 
    { 
     NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardDidShowNotification, object: nil); 
     NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil); 
    } 

    //MARK: Keyboard events 
    public func keyboardWasShown(notification: NSNotification) 
    { 

    } 

    public func keyboardWillHide(notification: NSNotification) 
    { 

    } 
}