Swift MKMapView将图钉注释添加到当前位置 [英] Swift MKMapView Drop a Pin Annotation to Current Location

问题描述

我希望能够向应用程序用户询问他/她的当前位置以及会自动放置在该位置上的图钉.这是我获取当前位置的代码，但是我很难理解如何为当前位置放置图钉.

I am looking to be able to ask the app user for his/her current location and a pin to be automatically dropped on that location. Here is my code for grabbing the current location, but I am having trouble understanding how I can drop a pin for the current location.

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.
}


}

推荐答案

如果您想将图钉添加到用户位置，则可以在didUpdateLocations委托方法中做到这一点

If you want to add pin to user location you can do that in didUpdateLocations delegate method like this

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)

}

为您的图钉创建全局变量

Create a global variable for your pin

let newPin = MKPointAnnotation()

因此，只要用户将移动到新位置，先前的图钉将被删除，新的图钉将被添加到更新的位置.

So whenever user will move to a new location the previous pin will be removed and a new pin will be added to updated location.

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