UIPanGestureRecognizer没有名为touchesBegan的成员

Question

我正在尝试继承UIPanGestureRecognizer，我想我可能会做一些愚蠢的事情。我试图覆盖UIPanGestureRecognizer从UIGestureRecognizer继承的方法时遇到错误。

我有这段代码

class VPGesture: UIPanGestureRecognizer {
    override func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesBegan(touches, withEvent: event)
    }

    override func touchesMoved(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesMoved(touches, withEvent: event);
    }

    override func touchesEnded(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesEnded(touches, withEvent: event);
    }

    override func touchesCancelled(touches: NSSet!, withEvent event: UIEvent!) {
        super.touchesCancelled(touches, withEvent: event);
    }
}

产生这些错误

非常感谢你的帮助。

Answer 1

当前接受的答案并不完全正确，实际上，如果要创建UIGestureRecognizer的子类，则应导入 UIGestureRecognizerSubclass.h 头文件，该文件在{{ 3}}，请参阅子类注释部分。

与Swift一样，这可以作为流程来完成：

import UIKit.UIGestureRecognizerSubclass

然后你准备好了。

Answer 2

您不必覆盖这些功能，您可以像下面一样定义它们。但我不确定为什么会这样。在自定义UIView中，必须覆盖这些函数。

func touchesBegan(touches: NSSet!, withEvent event: UIEvent!) {
    println("here")
}

func touchesMoved(touches: NSSet!, withEvent event: UIEvent!) {

}

func touchesEnded(touches: NSSet!, withEvent event: UIEvent!) {

}

func touchesCancelled(touches: NSSet!, withEvent event: UIEvent!) {

}