ios - 如何在 .Ended 状态下访问 Pan Gesture 的初始点

Question

我正在尝试在我的应用程序中实现一个平移手势，我需要在其中访问处于 .Ended 状态的初始点。

这是代码。

func handleTestViewTap (panRecognizer: UIPanGestureRecognizer){

    var locationOfBeganTap: CGPoint?

    if panRecognizer.state == UIGestureRecognizerState.Began {           
        locationOfBeganTap = panRecognizer.locationInView(view)
        print("locationOfBeganTap in BEGAN State -> .\(locationOfBeganTap)")

    } else if panRecognizer.state == UIGestureRecognizerState.Ended {            
        print("locationOfBeganTap -> .\(locationOfBeganTap)")
        print("locationOfBeganTap in ENDED State -> .\(locationOfBeganTap)")

    }     
}

现在，这是输出:

locationOfBeganTap in BEGAN State -> .Optional((195.5, 120.0))
locationOfBeganTap in ENDED State -> .nil

我无法理解为什么 locationOfBeganTap 在 .Ended 状态下为 nil

有人可以分享代码以在 .Ended 状态下访问 locationOfBeganTap...

Answer 1

您这样做的方式行不通。相反，在最后计算它:

func handleTestViewTap (panRecognizer: UIPanGestureRecognizer){

    if panRecognizer.state == UIGestureRecognizerState.Ended {            
        print("locationOfBeganTap -> (.\(touch.locationInView(view).x - touch.translationInView(view).x), .\(touch.locationInView(view).y - touch.translationInView(view).y))")
        print("location in ENDED State -> .\(touch.locationInView(view))")
    }     
}