如何在Google Maps ios的中心修复标记和GMSCircle？

Question

我想在地图的中心修复标记及其圆圈,而不管使用swift的位置坐标.如果用户在地图上移动相机,我希望它在中心不断出现任何闪烁,或者标记和用户应该能够增加和减少圆的半径.我用了

circle.position = mapView.camera.target

但它没有帮助.所以我想知道我该怎么做？请帮忙.

Answer 1

您的ViewController类需要实现该func mapView(mapView: GMSMapView!, didChangeCameraPosition position: GMSCameraPosition!)方法GMSMapViewDelegate.

在func mapView(mapView: GMSMapView!, didChangeCameraPosition position: GMSCameraPosition!)方法内,您可以更新圆的位置.在地图上的任何动画或手势期间重复调用该方法(或者,如果明确设置了相机,则调用一次).

示例代码:

class ViewController: UIViewController, GMSMapViewDelegate {

    var mapView: GMSMapView!
    var cirlce: GMSCircle!

    override func viewDidLoad() {
        super.viewDidLoad()
        let camera = GMSCameraPosition.cameraWithLatitude(-33.86,
            longitude: 151.20, zoom: 6)
        mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.myLocationEnabled = true
        self.view = mapView

        mapView.delegate = self

        cirlce = GMSCircle(position: camera.target, radius: 100000)
        cirlce.fillColor = UIColor.redColor().colorWithAlphaComponent(0.5)
        cirlce.map = mapView
    }

    func mapView(mapView: GMSMapView!, didChangeCameraPosition position: GMSCameraPosition!) {
        print("\(position.target.latitude) \(position.target.longitude)")
        cirlce.position = position.target
    }

}

编辑:

如果您想制作一个与mapView相机移动无关的圆圈,您可以在mapView上创建一个圆形UIView.

示例代码:

class ViewController: UIViewController {

    var mapView: GMSMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        let camera = GMSCameraPosition.cameraWithLatitude(-33.86,
            longitude: 151.20, zoom: 6)
        mapView = GMSMapView.mapWithFrame(CGRectZero, camera: camera)
        mapView.myLocationEnabled = true
        self.view = mapView

        let circleView = UIView()
        circleView.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.5)
        view.addSubview(circleView)
        view.bringSubviewToFront(circleView)
        circleView.translatesAutoresizingMaskIntoConstraints = false

        let heightConstraint = NSLayoutConstraint(item: circleView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 100)
        let widthConstraint = NSLayoutConstraint(item: circleView, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1, constant: 100)
        let centerXConstraint = NSLayoutConstraint(item: circleView, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1, constant: 0)
        let centerYConstraint = NSLayoutConstraint(item: circleView, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1, constant: 0)
        NSLayoutConstraint.activateConstraints([heightConstraint, widthConstraint, centerXConstraint, centerYConstraint])

        view.updateConstraints()
        UIView.animateWithDuration(1.0, animations: {
            self.view.layoutIfNeeded()
            circleView.layer.cornerRadius = CGRectGetWidth(circleView.frame)/2
            circleView.clipsToBounds = true
        })
    }
}