Question

我一直在四处寻找如何使用Swift 2.0为MapView制作MKCircle注释的一个很好的解释，但我似乎找不到充分的解释。有人可以发布一些示例代码来展示如何创建MKCircle注释吗？以下是我用于制作地图并获取坐标的代码。

let address = self.location

let geocoder = CLGeocoder()

    geocoder.geocodeAddressString(address, completionHandler: {(placemarks, error) -> Void in
        if((error) != nil){
            print("Error", error)
        }
        if let placemark = placemarks?.first {
            let coordinates:CLLocationCoordinate2D = placemark.location!.coordinate

            self.locationCoordinates = coordinates
            let span = MKCoordinateSpanMake(0.005, 0.005)
            let region = MKCoordinateRegion(center: self.locationCoordinates, span: span)
            self.CIMap.setRegion(region, animated: true)

            let annotation = MKPointAnnotation()
            annotation.coordinate = self.locationCoordinates
            self.CIMap.addAnnotation(annotation)

            self.CIMap.layer.cornerRadius = 10.0

            self.CIMap.addOverlay(MKCircle(centerCoordinate: self.locationCoordinates, radius: 1000))
        }
    })

Answer 1

首先，您需要将MKMapViewDelegate添加到类defenition。

 mapView.delegate = self

在viewDidLoad中将地图委托设置为自己。

设置注释

mapView.addOverlay(MKCircle(centerCoordinate: CLLocationCoordinate2D, radius: CLLocationDistance))

现在应该在mapViews委托中调用mapView rendererForOverlay并在那里绘制它

func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer {
    if let overlay = overlay as? MKCircle {
        let circleRenderer = MKCircleRenderer(circle: overlay)
        circleRenderer.fillColor = UIColor.blueColor()
        return circleRenderer
    }
}

此外，您需要导入MapKit才能编译

Answer 2

将使用带有xcode 8.3.3的swift 3显示如何在地图视图上创建圆形叠加的逐步方法

在你的主故事板文件中拖动地图工具包视图到故事板的场景（视图）并创建相同的插座，这里我创建了mapView。你也想在地图上长按时动态创建叠加，所以将长按手势识别器拖到对象库中的mapView上，然后为它创建动作方法，这里我创建了相同的addRegion（）。

为CLLocationManager类创建一个全局常量，以便可以在每个函数中访问它。在viewDidLoad方法中，添加一些代码以获取用户的授权。

    import UIKit  
    import MapKit

    class ViewController: UIViewController {


        @IBOutlet var mapView: MKMapView!
        let locationManager = CLLocationManager()

    override func viewDidLoad() {  
            super.viewDidLoad()

            locationManager.delegate = self
            locationManager.requestAlwaysAuthorization()
            locationManager.requestWhenInUseAuthorization()
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.startUpdatingLocation()

        }

在长按手势识别器操作方法addRegion（）中长按手势识别器时，添加用于生成圆形区域的代码。

    @IBAction func addRegion(_ sender: Any) {  
            print("addregion pressed")  
            guard let longPress = sender as? UILongPressGestureRecognizer else {return}

            let touchLocation = longPress.location(in: mapView)
            let coordinates = mapView.convert(touchLocation, toCoordinateFrom: mapView)
            let region = CLCircularRegion(center: coordinates, radius: 5000, identifier: "geofence")
            mapView.removeOverlays(mapView.overlays)
            locationManager.startMonitoring(for: region)
            let circle = MKCircle(center: coordinates, radius: region.radius)
            mapView.add(circle)

        }

在地图上渲染圆圈之前，你仍然不会在地图上看到圆圈。为此，您需要实现mapviewdelegate的委托。

        func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {}

为了使代码看起来更清晰，您可以在课程结束后的最后一个大括号后创建扩展名。一个扩展包含CLLocationManagerDelegate的代码和MKMapViewDelegate的其他代码。

    extension ViewController: CLLocationManagerDelegate {
        func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
            locationManager.stopUpdatingLocation()
            mapView.showsUserLocation = true
        }
    }

你应该在委托方法中调用locationManager.stopUpdatingLocation（），这样你的电池就不会耗尽。

        extension ViewController: MKMapViewDelegate {
            func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
                guard let circelOverLay = overlay as? MKCircle else {return MKOverlayRenderer()}

                let circleRenderer = MKCircleRenderer(circle: circelOverLay)
                circleRenderer.strokeColor = .blue
                circleRenderer.fillColor = .blue
                circleRenderer.alpha = 0.2
                return circleRenderer
            }
        }

这里我们在屏幕上制作实际的圆圈。

最终代码应如下所示。

import UIKit
import MapKit

class ViewController: UIViewController {


    @IBOutlet var mapView: MKMapView!
    let locationManager = CLLocationManager()

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager.delegate = self
        locationManager.requestAlwaysAuthorization()
        locationManager.requestWhenInUseAuthorization()
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.startUpdatingLocation()

    }

    // MARK: Long Press Gesture Recognizer Action Method

    @IBAction func addRegion(_ sender: Any) {
        print("addregion pressed")
        guard let longPress = sender as? UILongPressGestureRecognizer else {return}

        let touchLocation = longPress.location(in: mapView)
        let coordinates = mapView.convert(touchLocation, toCoordinateFrom: mapView)
        let region = CLCircularRegion(center: coordinates, radius: 5000, identifier: "geofence")
        mapView.removeOverlays(mapView.overlays)
        locationManager.startMonitoring(for: region)
        let circle = MKCircle(center: coordinates, radius: region.radius)
        mapView.add(circle)

    }

}

extension ViewController: CLLocationManagerDelegate {
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        locationManager.stopUpdatingLocation()
        mapView.showsUserLocation = true
    }
}

extension ViewController: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        guard let circelOverLay = overlay as? MKCircle else {return MKOverlayRenderer()}

        let circleRenderer = MKCircleRenderer(circle: circelOverLay)
        circleRenderer.strokeColor = .blue
        circleRenderer.fillColor = .blue
        circleRenderer.alpha = 0.2
        return circleRenderer
    }
}

Answer 3

叠加层只是一组数字。地图视图中可见的是叠加渲染器。您必须实施mapView:rendererForOverlay:才能提供叠加渲染器;否则，你什么也看不见。

如何在Swift中创建MKCircle？

3 个答案: