UIPanGestureRecognizer 没有名为 touchesBegan 的成员

Question

我正在尝试子类化 UIPanGestureRecognizer，我想我可能在做一些愚蠢的事情。尝试覆盖 UIPanGestureRecognizer 从 UIGestureRecognizer 继承的方法时出现错误。

我有这个代码

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

非常感谢您的帮助。

Answer 1

您不必重写这些函数，您可以像下面这样定义它们。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!) {

}

Answer 2

当前接受的答案不太正确，实际上，如果你想继承一个 UIGestureRecognizer，你应该导入 UIGestureRecognizerSubclass.h 头文件，在 https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIGestureRecognizer_Class/index.html 中描述，参见 子类化注释 部分。

与Swift一样，这可以按流程完成：

import UIKit.UIGestureRecognizerSubclass

那么你就可以开始了。

UIPanGestureRecognizer 没有名为 touchesBegan 的成员

UIPanGestureRecognizer does not have a member named touchesBegan

ios

iphone

cocoa-touch

swift

ios8