如何使“地图上的中心位置”起作用？

Posted 2023-03-05

【中文标题】如何使“地图上的中心位置”起作用？

【英文标题】：How do I make "Center location on Map" work?

【发布时间】：2017-02-14 17:55:08

【问题描述】：

我是编程新手。 我找到了下面的代码，它除了中心位置之外什么都做。（放大、地图、蓝点都可以。） 如果我在模拟器中运行，（城市运行）蓝点就会跑出页面。

import UIKit
import MapKit
import CoreLocation
import Foundation

class ViewController: UIViewController, CLLocationManagerDelegate 
    @IBOutlet weak var map: MKMapView!

    var locationManager: CLLocationManager?

    override func viewDidLoad() 
        super.viewDidLoad()

        locationManager = CLLocationManager()
        locationManager!.delegate = self

        map.showsUserLocation = true

        if CLLocationManager.authorizationStatus() == .authorizedWhenInUse 
            locationManager!.startUpdatingLocation()
         else 
            locationManager!.requestWhenInUseAuthorization()
        
    

    private func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) 
        switch status 
        case .notDetermined:
            print("NotDetermined")
        case .restricted:
            print("Restricted")
        case .denied:
            print("Denied")
        case .authorizedAlways:
            print("AuthorizedAlways")
        case .authorizedWhenInUse:
            print("AuthorizedWhenInUse")
            locationManager!.startUpdatingLocation()
        
    

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
        let location = locations.first!
        let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate, 500, 500)
        map.setRegion(coordinateRegion, animated: true)
        locationManager?.stopUpdatingLocation()
        locationManager = nil
    

【问题讨论】：

为什么不在地图视图上使用userTrackingMode 属性？

谢谢 Xoudini 我是编程新手，对 userTrackingMode 一无所知，所以我不知道如何使用它。

yourMapView.userTrackingMode = .follow 在定位服务开启时自动将用户居中，参见documentation。

或者setUserTrackingMode(_:animated:)。

【参考方案1】：

删除你的实现

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

只要获得授权，设置map.showsUserLocation = true，然后退后。

【参考方案2】：

这是我的 Swift 3 代码，它可以工作并经过测试。它加载 mapView，询问用户的许可并放大到他的位置。

import UIKit
import MapKit

class ViewController: UIViewController, CLLocationManagerDelegate 
@IBOutlet weak var mapView: MKMapView!

let locationManager = CLLocationManager()

override func viewDidLoad() 
    super.viewDidLoad()
    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
    locationManager.activityType = .automotiveNavigation
    locationManager.distanceFilter = 10.0
    mapView.showsUserLocation = true
    mapView.mapType = .standard
    self.mapView.delegate = self


override func viewWillAppear(_ animated: Bool) 
    super.viewWillAppear(animated)
    locationManager.requestWhenInUseAuthorization()
    locationManager.startUpdatingLocation()


func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
    let userLocation:CLLocation = locations[0] as CLLocation
    locationManager.stopUpdatingLocation()
    let location = CLLocationCoordinate2D(latitude: userLocation.coordinate.latitude, longitude: userLocation.coordinate.longitude)
    let span = MKCoordinateSpanMake(0.05, 0.05)
    let region = MKCoordinateRegion (center:  location,span: span)       
    mapView.setRegion(region, animated: true)

【讨论】：

谢谢 Mohsen 我在复制和粘贴您的代码时出错 无法将“ViewController”类型的值分配给“MKMapViewDelegate?”类型的值？

将 MKMapViewDelegate 作为协议添加到您的 viewController，或从您的代码中删除 mapView.delegate = self，您应该一切顺利，让我知道会发生什么

或 map.delegate = self，因为您在代码中将其命名为 map。