用UIPanGesture阻止UIView离开容器？

Question

我设法通过平移手势阻止我的UIView走出容器，但我正在努力实现的是阻止它的边缘。目前，它直接到达最后一个像素边缘，而不是可移动视图的边缘。

我尝试更改帧值，我认为这是要走的路，但无法产生正确的结果。不知道我有多接近或者有更简单的方法吗？

如何在可移动视图的边缘而不是最后一个像素处停止它？

//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，而不是限制手势，只是确保矩形不会超出范围：

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))

Answer 2

看起来您基于触摸的坐标而不是sender.view的框架来确定幻灯片中发件人视图的移动。

let senderViewFrame = self.view.convertRect(sender.view!.frame, fromView: sender.view!.superview)
let insetSenderViewFrame = CGRectInset(senderViewFrame, 0.0, 10.0 /*or whatever's needed*/)
let obstacleViewFrame = self.view.convertRect(self.sliderContainer.frame, fromView: self.sliderContainer.superview)

// Check if the sender view is inside the obstacle view
if CGRectContainsRect(obstacleViewFrame, insetSenderViewFrame) {
    sender.view!.center.x = sender.view!.center.x + translation.x
    sender.setTranslation(CGPointZero, inView: self.view)
}