使用 PanGestureRecognizer 在与另一个视图发生冲突之前检测视图的最后一个中心点？

Question

我有 2 个视图并使用以下代码检测它们的碰撞。如果对象移动缓慢，即它给出了运动中的坐标，则它工作正常。但是，当通过手势高速抛出视图时，中间坐标会被忽视。我只得到初始坐标和结束坐标。当两个视图发生碰撞时，我希望它们尽可能靠近。

func handlePan(_ pan: UIPanGestureRecognizer)
    {
        let view = pan.view
        switch pan.state
        {
        case .began, .changed, .possible, .ended:
            let point = pan.translation(in: view?.superview)
            print(point)
            let viewPoint = CGPoint(x: (view?.center.x)! + point.x, y: (view?.center.y)!+point.y)
            prevCenterB = viewBlue.center
            prevCenterR = viewRed.center
            view?.center = viewPoint
            if (viewRed.frame.intersects(viewBlue.frame))
            {
                print("Intersection")
                let alert = UIAlertController(title: "Alert", message: "Collision of objects occured !!", preferredStyle: UIAlertControllerStyle.alert)
                let actionOK = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: nil)
                let actionCancel = UIAlertAction(title: "Cancel", style: UIAlertActionStyle.cancel, handler: nil)
                alert.addAction(actionOK)
                alert.addAction(actionCancel)
                self.present(alert, animated: true, completion: nil)
                if view == viewRed
                {
                    view?.center = prevCenterR!
                }
                else
                {
                    view?.center = prevCenterB!
                }
            }
             pan.setTranslation(.zero, in: view?.superview)
            break
        default:
            break
        }

    }

Answer 1

可能值得一读 UIKit Dynamics 上的 Ray Wenderlich's tutorial。