ios - 位置正常，但无法追踪我在 Swift 3 中行驶的距离

Question

我正在为我的一门类(class)制作一个应用程序。它应该跟踪行驶的距离并更新标签以显示他们走了多远。当我打开应用程序时，它会请求跟踪位置的权限。 map View 可以工作，它跟随位置，但标签永远不会更新以显示行驶的距离。我在下面添加了我的代码，非常感谢任何帮助!

    //
    //  ViewController.swift
    //  location_tracker
    //
    //  Created by Dale McCaughan on 2016-10-19.
    //  Copyright © 2016 Dale McCaughan. All rights reserved.
    //

    import UIKit
    import CoreLocation
    import MapKit

    class ViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {

    @IBOutlet weak var theMap: MKMapView!
    @IBOutlet weak var l: UILabel!

    let locationManager = CLLocationManager()
    var startLocation: CLLocation!
    var monitoredRegions: Dictionary<String, NSDate> = [:]

    override func viewWillAppear(_ animated: Bool) {
        self.navigationController?.isNavigationBarHidden =  true
        self.navigationController?.isToolbarHidden = false;

    //Status bar style and visibility
    UIApplication.shared.statusBarStyle = .lightContent

    //Change status bar color
    let statusBar: UIView = UIApplication.shared.value(forKey: "statusBar") as! UIView
    //if statusBar.respondsToSelector("setBackgroundColor:") {
    statusBar.backgroundColor = UIColor.white
    //}

    UIToolbar.appearance().backgroundColor = UIColor.white

}

override func viewDidLoad() {
    super.viewDidLoad()

    //Setup the Location Manager
    locationManager.delegate = self;
    locationManager.distanceFilter = kCLLocationAccuracyNearestTenMeters;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    //Setup the Map View
    theMap.delegate = self
    theMap.showsUserLocation = true
    theMap.userTrackingMode = .follow

    // setup test data

}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    // status is not determined
    if CLLocationManager.authorizationStatus() == .notDetermined {
        locationManager.requestAlwaysAuthorization()
    }
        // authorization were denied
    else if CLLocationManager.authorizationStatus() == .denied {
        showAlert("Location services were previously denied. Please enable location services for this app in Settings.")
    }
        // we do have authorization
    else if CLLocationManager.authorizationStatus() == .authorizedAlways {
        locationManager.startUpdatingLocation()
    }
}

// MARK: - MKMapViewDelegate

func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
    let circleRenderer = MKCircleRenderer(overlay: overlay)
    circleRenderer.strokeColor = UIColor.red
    circleRenderer.lineWidth = 1.0
    return circleRenderer
}

@IBAction func resetDistance(_ sender: AnyObject) {
    startLocation = nil
}

// MARK: - CLLocationManagerDelegate

func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) {
    showAlert("enter \(region.identifier)")
    monitoredRegions[region.identifier] = Date() as NSDate?
    l.text = "in location manager1"
}

func locationManager(_ manager: CLLocationManager, didExitRegion region: CLRegion) {
    showAlert("exit \(region.identifier)")
    monitoredRegions.removeValue(forKey: region.identifier)
    l.text = "in location manager2"
}

var lastLocation: CLLocation!
var traveledDistance:Double = 0

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

    if let firstLocation = locations.first as? CLLocation
    {
        theMap.setCenter(firstLocation.coordinate, animated: true)

        let region = MKCoordinateRegionMakeWithDistance(firstLocation.coordinate, 1000, 1000)
        theMap.setRegion(region, animated: true)

        if let oldLocation = lastLocation {
            let delta: CLLocationDistance = firstLocation.distance(from: lastLocation)
            traveledDistance += delta
        }

        lastLocation = firstLocation
    }
    l.text = String(format: "%.3f", traveledDistance/1000) + " kilometers"

}

// MARK: - Helpers

func showAlert(_ title: String) {
    let alert = UIAlertController(title: title, message: nil, preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "Cancel", style: .default, handler: { (action) in
        alert.dismiss(animated: true, completion: nil)
    }))
    self.present(alert, animated: true, completion: nil)

}

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

Answer 1

试试这个:

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if let firstLocation = locations.first

您使用的委托(delegate)签名并不完全是委托(delegate)所寻找的。更正签名后，您不再需要 as CLLocation 转换。

我确认它适用于该更改。为了将来引用，您可以在 didUpdateLocations 设置一个断点，您会立即看到它没有被调用，然后从那里向后工作。

还要确保 Info.plist 包含所有必要的位置相关隐私字符串(我通常只放入所有三个以涵盖所有基础)。