SWIFT：核心位置返回 nil - 如何调用 didUpdateLocations？

Posted 2023-03-05

【中文标题】SWIFT：核心位置返回 nil - 如何调用 didUpdateLocations？

【英文标题】：SWIFT: Core Location returning nil - how to call didUpdateLocations?

【发布时间】：2016-06-21 18:08:07

【问题描述】：

我对核心位置有疑问，我已按照以下设置 https://***.com/a/24696878/6140339 这个答案，并将我所有的代码放在 AppDelegate 中，但我不知道如何调用它，所以我创建了另一个与 didUpdateLocations 执行相同操作的函数，并在我的 findMyLocation 按钮中调用它，它是只返回零。

我尝试在模拟器中设置自定义位置，仍然为零，我尝试使用调试器并设置位置，我什至尝试在我的 iphone 上测试它以查看是否可以获得位置，但仍然没有。

有没有办法从我的按钮调用 didUpdateLocations？ 还是我只是做错了我错过的其他事情。

这是我的 viewController 中的代码：

import UIKit
import Social
import CoreLocation

class FirstViewController: UIViewController

//let social = socialFunctions()
let locationManager = CLLocationManager()
let location = locationFunctions()
var locationFixAchieved = false
var currentLocation = CLLocation()

@IBOutlet weak var locationLabel: UILabel!

@IBAction func findMyLocation(sender: AnyObject) 
    updateLocation()
    print("Location: \(locationManager.location)")


@IBAction func postToFacebookButton(sender: UIButton) 
    postToFacebook()


@IBAction func postTweetButton(sender: UIButton) 
    postToTwitter()


override func preferredStatusBarStyle() -> UIStatusBarStyle 
    return .LightContent

override func viewDidLoad() 
    super.viewDidLoad()

override func didReceiveMemoryWarning() 
    super.didReceiveMemoryWarning()


//MARK: - SOCIAL FUNCTIONS
func postToFacebook()
    if(SLComposeViewController.isAvailableForServiceType(SLServiceTypeFacebook))
        let socialController = SLComposeViewController(forServiceType: SLServiceTypeFacebook)
        //creates post with pre-desired text
        socialController.setInitialText("")
        presentViewController(socialController, animated: true, completion: nil)
    


func postToTwitter()
    if(SLComposeViewController.isAvailableForServiceType(SLServiceTypeTwitter))
        let socialController = SLComposeViewController(forServiceType: SLServiceTypeTwitter)
        //creates post with pre-desired text
        socialController.setInitialText("")
        presentViewController(socialController, animated: true, completion: nil)
    


//MARK: - LOCATION FUNCTIONS
func updateLocation() 
    let locations = [CLLocation]()
    if (locationFixAchieved == false) 
        locationFixAchieved = true
        let locationArray = locations as NSArray
        let locationObj = locationArray.lastObject as? CLLocation
        let coord = locationObj?.coordinate
        if coord?.latitude != nil 
            locationLabel.text = ("Location \r\n Latitude: \(coord?.latitude) \r\n Longitude: \(coord?.longitude)")
            print("Latitude: \(coord?.latitude)")
            print("Longitude: \(coord?.longitude)")
         else 
            locationLabel.text = ("Could not find location")
            print("LAT & LONG are nil")
        
    

这是我添加到 appDelegate 中的代码

import UIKit
import CoreLocation
let fvc = FirstViewController()

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate, CLLocationManagerDelegate 

var window: UIWindow?
var locationManager: CLLocationManager!
var seenError : Bool = false
var locationFixAchieved: Bool = false
var locationStatus : NSString = "Not Started"

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject : AnyObject]?) -> Bool 
    initLocationManager();
    return true


func initLocationManager() 
    seenError = false
    locationFixAchieved = false
    locationManager = CLLocationManager()
    locationManager.delegate = self
    CLLocationManager.locationServicesEnabled()
    locationManager.desiredAccuracy = kCLLocationAccuracyBest

    locationManager.requestAlwaysAuthorization()


func locationManager(manager: CLLocationManager, didFailWithError error: NSError) 
    locationManager.stopUpdatingLocation()
    if (error == true) 
        if (seenError == false) 
            seenError = true
            print(error)
        
    


func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
        let locations = [CLLocation]()
        if (locationFixAchieved == false) 
            locationFixAchieved = true
            let locationArray = locations as NSArray
            let locationObj = locationArray.lastObject as? CLLocation
            let coord = locationObj?.coordinate

            print("Latitude: \(coord?.latitude)")
            print("Longitude: \(coord?.longitude)")
            //fvc.locationLabel.text = ("Location \r\n Latitude: \(coord?.latitude) \r\n Longitude: \(coord?.longitude)")
    


func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) 
    var shouldIAllow = false

    switch status 
    case CLAuthorizationStatus.Restricted:
        locationStatus = "Restricted Access to location"
    case CLAuthorizationStatus.Denied:
        locationStatus = "User denied access to location"
    case CLAuthorizationStatus.NotDetermined:
        locationStatus = "Status not determined"
    default:
        locationStatus = "Allowed location Access"
        shouldIAllow = true
    
    NSNotificationCenter.defaultCenter().postNotificationName("LabelHasBeenUpdated", object: nil)
    if (shouldIAllow == true) 
        NSLog("Location Allowed")
        //Start location services
        locationManager.startUpdatingLocation()
     else 
        NSLog("Denied access: \(locationStatus)")
    

【问题讨论】：

didUpdateLocations 方法中的第一行会丢弃传入的位置并将其替换为空数组

@dan let locations = [CLLocation]()?那我怎么称呼这个位置呢？

【参考方案1】：

按照 dan 的评论（谢谢），我所要做的就是删除第一行，它显示了坐标，我还没有弄清楚如何调用我的函数来更改标签文本，但我会在我想通了。编辑：在下面发布解决方案

我变了

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) 
    let locations = [CLLocation]()
    if (locationFixAchieved == false) 
        locationFixAchieved = true
        let locationArray = locations as NSArray
        let locationObj = locationArray.lastObject as? CLLocation
        let coord = locationObj?.coordinate

        print("Latitude: \(coord?.latitude)")
        print("Longitude: \(coord?.longitude)")
        //fvc.locationLabel.text = ("Location \r\n Latitude: \(coord?.latitude) \r\n Longitude: \(coord?.longitude)")

删除let locations = [CLLocation]()

这就是我按下按钮时的调用方式。

func updateLocation() 
    let manager = CLLocationManager()
    let locValue : CLLocationCoordinate2D = (manager.location?.coordinate)!;
    let long = locValue.longitude
    let lat = locValue.latitude
    print(long)
    print(lat)
    locationLabel.text = ("Location \r\nLatitude: \(lat) \r\nLongitude: \(long)")