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。我使用了

circle.position = mapView.camera.target

，但没有用。所以我想知道我该怎么做？请帮忙。

Answer 1

您的ViewController课程需要实施func mapView(mapView: GMSMapView!, didChangeCameraPosition position: GMSCameraPosition!)中的GMSMapViewDelegate方法。

在func mapView(mapView: GMSMapView!, didChangeCameraPosition position: GMSCameraPosition!)方法中，您可以更新圆圈的位置。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，则重复一次）。

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
    }

}

<强>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
        })
    }
}

Answer 2

这是Swift 3

的更新版本

import UIKit
import GoogleMaps

class ViewController: UIViewController, GMSMapViewDelegate {

var mapView: GMSMapView!

override func viewDidLoad() {
    super.viewDidLoad()

    let camera = GMSCameraPosition.camera(withLatitude: -33.86,
                                          longitude: 151.20, zoom: 6)
    mapView = GMSMapView.map(withFrame: .zero, camera: camera)
    mapView.isMyLocationEnabled = true
    self.view = mapView

    mapView.delegate = self

    let circleView = UIView(frame: CGRect(x: 0, y: 0, width: 20, height: 10))
    circleView.backgroundColor = UIColor.red.withAlphaComponent(0.5)
    view.addSubview(circleView)
    view.bringSubview(toFront: 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.activate([heightConstraint, widthConstraint, centerXConstraint, centerYConstraint])

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

}
func mapView(_ mapView: GMSMapView, didChange position: GMSCameraPosition) {
    print("\(position.target.latitude) \(position.target.longitude)")
     } 
}

如何在Google Maps ios的中心修复标记和GMSCircle？

2 个答案:

这是Swift 3