swift - Swift 4 map 未显示用户当前位置

我试图在地图上显示用户的当前位置，但没有任何效果。我哪里做错了？

import UIKit
import CoreLocation
import MapKit

class MapViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

    var window: UIWindow?
    var mapView: MKMapView?
    let locationManager = CLLocationManager()

    let distanceSpan: Double = 500

    override func viewDidLoad() {
        super.viewDidLoad()

        setupNavBar()
        setupMapView()
        setupLocationManager()
    }

    fileprivate func setupNavBar() {
        self.navigationItem.title = "Near By"
        self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Back", style: .done, target: self, action: #selector(handleDissmiss))
    }

    fileprivate func setupLocationManager() {self.locationManager.requestWhenInUseAuthorization()

        if CLLocationManager.locationServicesEnabled() {
            locationManager.delegate = self
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.startUpdatingLocation()
        }

    }

    fileprivate func setupMapView() {
        self.window = UIWindow(frame: UIScreen.main.bounds)
        self.view.backgroundColor = UIColor.white
        self.mapView?.showsUserLocation = true
        self.mapView = MKMapView(frame: CGRect(x: 0, y: 20, width: (self.window?.frame.width)!, height: view.frame.height))
        self.view.addSubview(self.mapView!)
    }

最佳答案

在分配mapView之前，您正在设置showUserLocation属性。
在将来，为了避免这种错误，您可以使用不同的编码风格，而不使用可选的例如。

 fileprivate func setupMapView() {
    let mView = MKMapView(frame: CGRect(x: 0, y: 20, width: view.frame.width, height: view.frame.height))
    mView.showsUserLocation = true
    view.addSubview(mView)
    self.mapView = mView
}

此外，确保Info.plist包含nslocationwhenninuseagedescription键-如文档所述https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CocoaKeys.html