有两种选择：

1. 我发现，通常来说，如果在删除旧的叠加层之前添加新的叠加层，则闪烁效果会减弱。

2. 您可以考虑将圆设为自定义注释视图，而不是叠加层。这样，您只需调整coordinate即可，而无需添加/删除。

通过将圆圈放入注解本身，可以实现无缝衔接，并且都可以跟踪用户：

我关闭了用户跟踪的一半，所以您可以看到两种模式。

class CirclePointerAnnotationView: MKAnnotationView {
    let circleShapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = UIColor.lightGray.withAlphaComponent(0.25).cgColor
        shapeLayer.strokeColor = UIColor.clear.cgColor
        return shapeLayer
    }()

    let pinShapeLayer: CAShapeLayer = {
        let shapeLayer = CAShapeLayer()
        shapeLayer.fillColor = UIColor.blue.cgColor
        shapeLayer.strokeColor = UIColor.clear.cgColor
        return shapeLayer
    }()

    let imageView: UIImageView = {
        let imageView = UIImageView()
        imageView.contentMode = .scaleAspectFill
        imageView.image = UIImage(named: "woman")
        imageView.clipsToBounds = true
        return imageView
    }()

    var pinHeight: CGFloat = 100
    var pinRadius: CGFloat = 30
    var annotationViewSize = CGSize(width: 300,height: 300)

    override init(annotation: MKAnnotation?,reuseIdentifier: String?) {
        super.init(annotation: annotation,reuseIdentifier: reuseIdentifier)

        layer.addSublayer(circleShapeLayer)
        layer.addSublayer(pinShapeLayer)
        addSubview(imageView)

        bounds.size = annotationViewSize
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func layoutSubviews() {
        let radius = min(bounds.width,bounds.height) / 2
        let center = CGPoint(x: bounds.midX,y: bounds.midY)
        circleShapeLayer.path = UIBezierPath(arcCenter: center,radius: radius,startAngle: 0,endAngle: 2 * .pi,clockwise: true).cgPath

        let angle = asin(pinRadius / (pinHeight - pinRadius))
        let pinCenter = CGPoint(x: center.x,y: center.y - (pinHeight - pinRadius))
        let path = UIBezierPath()
        path.move(to: center)
        path.addArc(withCenter: pinCenter,radius: pinRadius,startAngle: .pi - angle,endAngle: angle,clockwise: true)
        path.close()
        pinShapeLayer.path = path.cgPath

        let imageViewDimension = pinRadius * 2 - 15
        imageView.bounds.size = CGSize(width: imageViewDimension,height: imageViewDimension)
        imageView.center = pinCenter
        imageView.layer.cornerRadius = imageViewDimension / 2
    }
}