UIView 子视图被放置在意外的位置 (Swift 4)

UIView subview being placed in unexpected position (Swift 4)

我正在尝试将 4 个 UIView 子视图添加到 UIImageView。这些子视图将充当节点,用户可以在其中点击它们并连接到其他节点。例如,他们应该看 like this. Instead, they are looking like this.

我计算节点位置的代码如下:

func initializeConnectionNodes() {
        let imageCenter = self.imageView.center
        let xOffset = self.imageView.bounds.width/2 //distance from origin x-wise
        let yOffset = self.imageView.bounds.height/2 //distance from origin y-wise
        self.leftConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: imageCenter.x - xOffset, y: imageCenter.y))
        self.rightConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: imageCenter.x + xOffset, y: imageCenter.y))
        self.topConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: imageCenter.x, y: imageCenter.y + yOffset))
        self.bottomConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: imageCenter.x, y: imageCenter.y - yOffset))

        self.imageView.addSubview(self.leftConnectionNode!)
        self.imageView.addSubview(self.rightConnectionNode!)
        self.imageView.addSubview(self.topConnectionNode!)
        self.imageView.addSubview(self.bottomConnectionNode!)
}

我的UIView初始化代码class如下:

class ConnectionNodeView: UIView {

var connectionPoint: CGPoint
fileprivate var circleLayer: CAShapeLayer?

init(connectionPoint: CGPoint) {
    self.connectionPoint = connectionPoint
    super.init(frame: CGRect(x: connectionPoint.x, y: connectionPoint.y, width: 0, height: 0))

    let circlePath = UIBezierPath(arcCenter: connectionPoint, radius: CGFloat(8), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)
    self.circleLayer = CAShapeLayer()
    self.circleLayer?.path = circlePath.cgPath
    self.circleLayer?.fillColor = UIColor.yellow.cgColor
    self.circleLayer?.strokeColor = UIColor.yellow.cgColor
    self.circleLayer?.lineWidth = 3.0
    self.layer.addSublayer(circleLayer!)
}

有趣的是,如果我只是将 CAShapeLayer 作为子层添加到我的 UIImageView,它看起来应该如此。但是,我需要将其实现为 UIView,以便我可以轻松地使用手势识别器。我找到了一种修复它的肮脏方法,方法是在初始化程序中将坐标除以 100,如下所示:

super.init(frame: CGRect(x: connectionPoint.x/100, y: connectionPoint.y/100, width: 0, height: 0))

但是,我宁愿做正确的事。我在这里错过了什么?感谢您的帮助。

您正在将视图添加到图像视图,但是 imageCenter 点是根据图像视图的 superview 给出的。

initializeConnectionNodes 函数的开头替换为以下内容:

let xCenter = imageView.bounds.width / 2
let yCenter = imageView.bounds.height / 2

leftConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: 0, y: yCenter))
rightConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: imageView.bounds.width, y: yCenter))
topConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: xCenter, y: 0))
bottomConnectionNode = ConnectionNodeView(connectionPoint: CGPoint(x: xCenter, y: imageView.bounds.height))

此外,您应该将 ConnectionNodeView 子类中 circlePath 的圆弧中心替换为 CGPoint.zero,因为它适用于节点视图本身的坐标系:

let circlePath = UIBezierPath(arcCenter: .zero, radius: 8, startAngle: 0, endAngle:CGFloat(Double.pi * 2), clockwise: true)