ios - 使用 UIPanGesture 停止 UIView 离开容器？

Question

我已经设法用平移手势阻止我的 UIView 离开容器，但我正在努力实现的是将它停止在容器的边缘。目前它正好到达最后一个像素边缘，而不是可移动 View 的边缘。

我尝试更改我认为可行的帧值，但无法产生正确的结果。不确定我有多接近或是否有更简单的方法？

我如何将它停在可移动 View 的边缘而不是最后一个像素？

//Container is self.sliderContainer
//Green Block is sender.view which has a UIGesture applied

    var location = sender.locationInView(self.view)

    var newFrame = CGRectMake(0, 0, self.sliderContainer.frame.width, self.sliderContainer.frame.height)

    let obstacleViewFrame = self.view.convertRect(self.sliderContainer.frame, fromView: self.sliderContainer.superview)

        // Check if the touch is inside the obstacle view
        if CGRectContainsPoint(obstacleViewFrame, location) {

            sender.view!.center.x = sender.view!.center.x + translation.x

            sender.setTranslation(CGPointZero, inView: self.view)
        }

Answer 1

我建议以最简单的方式来做，不限制手势，只确保 rect 不会越界:

let movingView = sender.view!
let minCenterX = movingView.frame.size.width / 2
let maxCenterX = self.sliderContainer.frame.width - movingView.frame.size.width / 2

let newCenterX = movingView.center.x + translation.x
movingView.center.x = min(maxCenterX, max(minCenterX, newCenterX))