在 xcode/swift 中使用位置管理器來獲取用戶的當前位置時，我得到的值為 nil。 有什么建議么？

Question

*更新：現在獲取位置數據，打印語句print("\(currentLocation.coordinate.latitude)")有效。 如果我嘗試將 = 右側的內容分配給 label.text 值，則會出現錯誤：在展開可選值時意外發現 nil。 *對整個 Swift/Xcode 來說還是個新手。 任何幫助將不勝感激。 我正在運行以下代碼（僅與所示問題相關的代碼）。 當用戶按下按鈕並選擇獲取位置時，它應該獲取他們的位置。 相反，我什么也得不到。 locationManager 中的文本從不打印，我很茫然。

import UIKit
import MapKit
import CoreLocation
import MessageUI
import Photos
import AVFoundation

class ViewController: UIViewController, UITextViewDelegate, UINavigationControllerDelegate, UIImagePickerControllerDelegate, CLLocationManagerDelegate, MFMailComposeViewControllerDelegate {
    var locationManager: CLLocationManager()
    var currentLocation: CLLocation?

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager.requestWhenInUseAuthorization()
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
        locationManager.startUpdatingLocation()
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let currentLocation = locations[0]
        print("\(currentLocation.coordinate.latitude)")
        issueLocation.text = "\(currentLocation.coordinate.latitude)" ***ERROR***
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("Error: \(error)")
    }

沒關系的東西，我希望，還有更多代碼

    // Attach a location
    @IBAction func attachLocation(_ sender: UIButton) {
        if issueLocation.text == nil {
            issueImage.isHidden = true
        }

        let alertController = UIAlertController(title: "Location options", message: nil, preferredStyle: .actionSheet)

        // Get location
        let locationAction = UIAlertAction(title: "Get location", style: .default) { (action) in
            self.displayLocation()

        }    

        // Add get location action to alert controller
        alertController.addAction(locationAction)

        // Remove location
        let eraseLocation = UIAlertAction(title: "Erase location", style: .default) { (action) in
            self.issueLocation.text == nil
            self.issueLocation.isHidden = true
        }

        // Add erase location to alert controller
        alertController.addAction(eraseLocation)

        // Cancel action
        let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
            // Do nothing
        }

        // Add cancel action to alert controller
        alertController.addAction(cancelAction)

        // Display alert message on screen
        self.present(alertController, animated: true) {
            // Code to handle user selection
        }
    }

    func displayLocation() {
        let status = CLLocationManager.authorizationStatus()
        let noPermissionMessage = "It appears that LoCAL Information does not have access to your location. Click Settings -> LoCAL Information -> Location to allow access to your location."

        switch status {
        case .notDetermined:
            locationManager?.requestWhenInUseAuthorization()
        case .authorized, .authorizedAlways, .authorizedWhenInUse:
            print("JJJJJ")
            print("KKKKK")
            issueLocation.isHidden = false
        case .denied, .restricted:
            self.troubleAlert(message: noPermissionMessage)
        @unknown default:
            self.troubleAlert(message: noPermissionMessage)
        }

    }

Answer 1

locationManager已聲明但未初始化

代替

var locationManager: CLLocationManager?

和

let locationManager = CLLocationManager()

並在每次出現locationManager后刪除問號