Question

我正在尝试在KeyboardScrollController课程中获取键盘通知，但我为UIKeyboardWillHideNotification和UIKeyboardDidShowNotification设置了无法识别的选择器。

这是我的简单实现：

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)
    {

    }
}

但每次出现键盘时都会出现此错误：

*** NSForwarding：警告：类'KeyboardScrollController'的对象0x7fdc8d882730没有实现methodSignatureForSelector： - 提前出现问题无法识别的选择器 - [KeyboardScrollController keyboardWillHide：]

我尝试了Selecor("keyboardWillHide:")，但这没有任何区别。

这里有什么问题？我已经在Objective-C中多次实现了这个，但我无法在Swift中使用它。

Answer 1

啊，它突然袭击了我，问题可能是什么。我必须继承NSObject才能使其发挥作用：

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)
    {

    }
}

UIKeyboardWillHideNotification上无法识别的选择器

1 个答案: