如何将 UIPanGestureRecognizer 添加到在 CAShapLayer 上绘制的形状 - swift？

Question

我有一个 imageView，我在其图层中绘制了一个蓝色圆圈。我希望用户能够在 UIImageView 中的任何位置点击、按住并拖动这个蓝色圆圈。我不确定如何将此形状附加到 UIPanGestureRecognizer。到目前为止，我的努力如下：

class DrawCircleViewController: UIViewController {

    @IBOutlet weak var imgView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // DRAW A FILLED IN BLUE CIRCLE
        drawBlueCircle()

        // ADD GESTURE RECOGNIZER
        let panRecgonizer = UIPanGestureRecognizer.init(target: ???, action: <#T##Selector?#>)

    }

    func drawBlueCircle(){
        let fourDotLayer = CAShapeLayer()
        fourDotLayer.path = UIBezierPath.init(roundedRect: CGRect.init(x: 60, y: 60, width: 30, height: 30), cornerRadius: 50).cgPath
        fourDotLayer.fillColor = UIColor.blue.cgColor
        self.imgView.layer.addSublayer(fourDotLayer)
    }
}

Answer 1

您可能已经注意到，您无法将 GestureRecognizers 添加到 CALayers。它们只能添加到 UIView 类型。

解决方法是在你的图像视图中添加一个子视图，并在其中绘制蓝色圆圈。

    var drawingView: UIView?
    override func viewDidLoad() {
        super.viewDidLoad()
        drawingView.frame = imgView.bounds
        imgView.addSubview(drawingView)
        // DRAW A FILLED IN BLUE CIRCLE
        drawBlueCircle()
        // ADD GESTURE RECOGNIZER
        let panRecgonizer = UIPanGestureRecognizer(target: drawingView, action: #selector())
drawingView.addGestureRecognizer(panRecgonizer)
    }
    func drawBlueCircle(){
        let fourDotLayer = CAShapeLayer()
        fourDotLayer.path = UIBezierPath.init(roundedRect: CGRect.init(x: 60, y: 60, width: 30, height: 30), cornerRadius: 50).cgPath
        fourDotLayer.fillColor = UIColor.blue.cgColor
        drawingView?.layer.addSublayer(fourDotLayer)
    }

Answer 2

使用此代码移动视图

@objc func handlePanRecgonizer(_ gestureRecognizer: UIPanGestureRecognizer){
     if panRecgonizer.state == .began || panRecgonizer.state == .changed {
        let translation = panRecgonizer.translation(in: self.view)
        panRecgonizer.view!.center = CGPoint(x: panRecgonizer.view!.center.x + translation.x, y: panRecgonizer.view!.center.y + translation.y)
        panRecgonizer.setTranslation(CGPoint.zero, in: self.view)
    }
}

如果您想以编程方式添加 UIPanGestureRecognizer：

let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePanRecgonizer))
 self.someDraggableView.addGestureRecognizer(gestureRecognizer)

如何将 UIPanGestureRecognizer 添加到在 CAShapLayer 上绘制的形状 - swift？

How to add a UIPanGestureRecognizer to an shape drawn on CAShapLayer - swift?

ios

swift

uipangesturerecognizer