如何：点击时将视图置于前面；设置最大/最小捏合手势比例；将屏幕限制设置为平移手势

注意：我发现的所有东西都太旧了，或者与我实际需要的东西相差太大，而且我几乎尝试了我发现的所有东西，但没有一个能以正确的方式工作。

我创建了 3 个 UIView，我可以拖动它们并缩放它们。 现在，我需要：

1. 将其中一些放在前面：我想为每个添加一个 UITapGesture 允许我将点击的 UIView 带到前面 将其他 UIView 传递到后面；
2. 为 UIPinchGestureRecognizer 设置最大/最小比例，以便我 不能有超大的 UIiews 或微小的 UIViews；
3. 为 UIPanGestureRecognizer 设置某种屏幕限制，以便我 无法将我的 UIView 拖到主视图之外。

这是我的代码：

https://github.com/marybnq/Views https://github.com/marybnq/Views

我解决了我的问题！

1. 我想出了如何为 UIPinchGestureRecognizer 设置最大/最小比例，这就是我所做的。

    var recognizerScale:CGFloat = 1.0
    var maxScale:CGFloat = 1.5
    var minScale:CGFloat = 0.8

    @IBAction func handlePinch(_ pinchGesture: UIPinchGestureRecognizer) {
        guard pinchGesture.view != nil else {return}

        if pinchGesture.state == .began || pinchGesture.state == .changed{
            if (recognizerScale < maxScale && pinchGesture.scale > 1.0) {
                pinchGesture.view?.transform = (pinchGesture.view?.transform)!.scaledBy(x: pinchGesture.scale, y: pinchGesture.scale)
                recognizerScale *= pinchGesture.scale
                pinchGesture.scale = 1.0
            }
            if (recognizerScale > minScale && pinchGesture.scale < 1.0) {
                pinchGesture.view?.transform = (pinchGesture.view?.transform)!.scaledBy(x: pinchGesture.scale, y: pinchGesture.scale)
                recognizerScale *= pinchGesture.scale
                pinchGesture.scale = 1.0
            }
        }
    }

2. 为了将视图带到前面，我创建了多个 UIPanGestureRecognizer 并添加了 BringSubviewToFront：

     @IBAction func handlePan1(recognizer:UIPanGestureRecognizer) {
        let translation = recognizer.translation(in: self.view)
        if let view = recognizer.view {
            view.center = CGPoint(x:view.center.x + translation.x,
                                  y:view.center.y + translation.y)
        }
        view.bringSubviewToFront(view1)
        recognizer.setTranslation(CGPoint.zero, in: self.view)
    }

     @IBAction func handlePan2(recognizer:UIPanGestureRecognizer) {
        let translation = recognizer.translation(in: self.view)
        if let view = recognizer.view {
            view.center = CGPoint(x:view.center.x + translation.x,
                                  y:view.center.y + translation.y)
        }
        view.bringSubviewToFront(view2)
        recognizer.setTranslation(CGPoint.zero, in: self.view)
    }

ecc... 但是如果您还想限制平移手势，则无法执行此操作，因此您可能需要添加点击手势识别器：

将gestureRecognizer添加到您的视图中并设置委托。

@IBAction func tappedView1(recognizer: UITapGestureRecognizer) {
        view.bringSubviewToFront(myView)
    }

在你看来DidLoad：

 let tap = UITapGestureRecognizer(target: self, action: #selector(tappedView1))
        tap.cancelsTouchesInView = false
        self.view.addGestureRecognizer(tap)

3. 要设置屏幕限制/平移限制，我找到了以下代码：

@IBAction func handlePan(recognizer:UIPanGestureRecognizer) {
        let translation = recognizer.translation(in: self.view)
        let statusFrame = UIApplication.shared.statusBarFrame


        if let recognizerView = recognizer.view {
            if recognizerView.frame.origin.x < 0.0 {
                recognizerView.frame.origin = CGPoint(x: 0.0, y: recognizerView.frame.origin.y)
            }
            if recognizerView.frame.origin.y < statusFrame.height {
                recognizerView.frame.origin = CGPoint(x: recognizerView.frame.origin.x, y: statusFrame.height)
            }
            if recognizerView.frame.origin.x + recognizerView.frame.size.width > view.frame.width {
                recognizerView.frame.origin = CGPoint(x: view.frame.width - recognizerView.frame.size.width, y: recognizerView.frame.origin.y)

            }
            if recognizerView.frame.origin.y + recognizerView.frame.size.height > view.frame.height {
                recognizerView.frame.origin = CGPoint(x: recognizerView.frame.origin.x, y: view.frame.height - recognizerView.frame.size.height)
            }
        }

        if let centerX = recognizer.view?.center.x, let centerY = recognizer.view?.center.y {
            recognizer.view?.center = CGPoint.init(x: centerX + translation.x , y: centerY + translation.y)
            recognizer.setTranslation(CGPoint.zero, in: self.view)
        }

        view.bringSubviewToFront(view1)
        recognizer.setTranslation(CGPoint.zero, in: self.view)
}