Swift MKMapView 将 Pin 注释放到当前位置

Question

我希望能够向应用用户询问 his/her 当前位置，并在该位置自动放置一个图钉。这是我获取当前位置的代码，但我无法理解如何为当前位置放置图钉。

import UIKit
import MapKit
import CoreLocation


class MapVC: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {



@IBOutlet weak var map: MKMapView!

let locationManager =  CLLocationManager()

override func viewDidLoad() {
    super.viewDidLoad()

    // User's location

    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    if #available(iOS 8.0, *) {
        locationManager.requestAlwaysAuthorization()
    } else {
        // Fallback on earlier versions
    }
    locationManager.startUpdatingLocation()

    // add gesture recognizer
    let longPress = UILongPressGestureRecognizer(target: self, action: #selector(MapVC.mapLongPress(_:))) // colon needs to pass through info
    longPress.minimumPressDuration = 1.5 // in seconds
    //add gesture recognition
    map.addGestureRecognizer(longPress)
}

// func called when gesture recognizer detects a long press

func mapLongPress(_ recognizer: UIGestureRecognizer) {

    print("A long press has been detected.")

    let touchedAt = recognizer.location(in: self.map) // adds the location on the view it was pressed
    let touchedAtCoordinate : CLLocationCoordinate2D = map.convert(touchedAt, toCoordinateFrom: self.map) // will get coordinates

    let newPin = MKPointAnnotation()
    newPin.coordinate = touchedAtCoordinate
    map.addAnnotation(newPin)


}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    let location = locations.last! as CLLocation

    let center = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))




    //set region on the map
    self.map.setRegion(region, animated: true)



}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


}

Answer 1

首先您需要在 didUpdateLocations 方法中添加注释，然后每当添加任何注释时都会调用 viewForAnnotation 所以这里是在用户当前位置添加 pin 的代码和相应方法：

//在当前位置添加注释

 func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        //Get Current Location
        let location = locations.last! as CLLocation
        let userLocation:CLLocation = locations[0] as CLLocation
        let myAnnotation: MKPointAnnotation = MKPointAnnotation()
        myAnnotation.coordinate = CLLocationCoordinate2DMake(userLocation.coordinate.latitude, userLocation.coordinate.longitude)
        myAnnotation.title = "Current location"
        map.addAnnotation(myAnnotation)
}

//将图像添加到用户当前位置pin

    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {

   guard !(annotation is MKUserLocation) else {
            let annotationView = MKAnnotationView(annotation: annotation, reuseIdentifier: "userLocation")
            annotationView.image = UIImage(named:"anyimage.png")
            return annotationView
        }
return nil
}

如有任何问题，请随时询问。

Answer 2

如果你想将 pin 添加到用户位置，你可以在 didUpdateLocations 委托方法中这样做

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    mapView.removeAnnotation(newPin)

    let location = locations.last! as CLLocation

    let center = CLLocationCoordinate2D(latitude: location.coordinate.latitude, longitude: location.coordinate.longitude)
    let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))        

    //set region on the map
    map.setRegion(region, animated: true)

    newPin.coordinate = location.coordinate
    map.addAnnotation(newPin)

}

为你的 pin 创建一个全局变量

let newPin = MKPointAnnotation()

因此，每当用户移动到新位置时，以前的图钉将被删除，新图钉将添加到更新后的位置。

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