Swift 4、Xcode 9：获取并显示用户位置遇问题求助

Hey there! I totally get how frustrating this can be when you're just starting out with MapKit. Let's break down why your simulator is only showing your country instead of a precise location, and how to fix it:

Why This Happens #

First off, iOS simulators don't use real GPS data by default. They either use a default location (like Apple's headquarters in Cupertino) or an approximate location based on your IP address (which is why you only see your country). To get a precise location, you need to manually set a custom location in the simulator.

Step 1: Set a Custom Location in the Simulator #

This is the quickest fix:

• Launch your app in the simulator.
• Go to the simulator's top menu bar: Debug → Location.
• Instead of the default Current Location (which is imprecise), select Custom Location.
• Enter any latitude and longitude you want (e.g., 39.9042, 116.4074 for Beijing, or 40.7128, -74.0060 for New York) and hit Enter. Your map should immediately zoom to that spot.

Alternatively, you can pick one of the preset locations under Debug → Location (like "Apple, Cupertino") to test with a known point.

Step 2: Tweak Your Code for Better Behavior #

Your code is mostly solid, but there are a few small improvements to make it more reliable:

• Don't repeat map settings in didUpdateLocations: Setting mapType and showsUserLocation every time the location updates is unnecessary. Move these to viewDidLoad instead.
• Use the latest location, not the first: The locations array can have multiple entries—always grab the last one (it's the most recent).
• Use modern initializers: MKCoordinateSpanMake is deprecated; use MKCoordinateSpan(latitudeDelta:longitudeDelta:) instead.

Here's the revised code:

import UIKit
import CoreLocation
import MapKit

class ViewController: UIViewController, CLLocationManagerDelegate {

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

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        // Grab the most recent location
        guard let latestLocation = locations.last else { return }
        let userCoordinate = latestLocation.coordinate
        
        // Define the map region (zoom level)
        let zoomSpan = MKCoordinateSpan(latitudeDelta: 0.05, longitudeDelta: 0.05)
        let targetRegion = MKCoordinateRegion(center: userCoordinate, span: zoomSpan)
        
        // Update the map
        mapView.setRegion(targetRegion, animated: true)
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Configure mapView once
        mapView.mapType = .standard
        mapView.showsUserLocation = true
        
        // Set up location manager
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        
        // Request location permission
        if CLLocationManager.authorizationStatus() == .notDetermined {
            // Use this for foreground-only access
            locationManager.requestWhenInUseAuthorization()
            // Uncomment below if you need background access (ensure Info.plist has the right key)
            // locationManager.requestAlwaysAuthorization()
        }
        
        // Start updating location if services are enabled
        if CLLocationManager.locationServicesEnabled() {
            locationManager.startUpdatingLocation()
        }
    }

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

Step 3: Double-Check Permissions #

You mentioned adding privacy keys to Info.plist, but make sure you're using the correct ones for iOS 11+:

• For "When In Use" permission: Add NSLocationWhenInUseUsageDescription with a clear message (e.g., "We need your location to show you on the map").
• For "Always" permission: Add NSLocationAlwaysAndWhenInUseUsageDescription (this replaces the old NSLocationAlwaysUsageDescription for newer iOS versions).

Empty description strings will cause permission requests to fail, so don't skip adding a meaningful message!

Final Note #

On a real iOS device, this code will automatically use the device's GPS to get your precise location—this issue is unique to simulators. Once you set a custom location in the simulator, your app should behave exactly as you expect.

内容的提问来源于stack exchange，提问作者jcdr04