getUserLocation.swift

import UIKit
import CoreLocation



class TableViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, CLLocationManagerDelegate {
    var myLocationManager : CLLocationManager = CLLocationManager()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        myLocationManager.delegate = self
        myLocationManager.distanceFilter = kCLLocationAccuracyNearestTenMeters
        myLocationManager.desiredAccuracy = kCLLocationAccuracyBest
      
        if CLLocationManager.authorizationStatus() == .denied {
            self.myUserDefaults.set(false, forKey: userLocationAuth)
            self.myUserDefaults.synchronize()
            DispatchQueue.main.async(){
                let alertController = UIAlertController(title: "定位權限已關閉", message: "如要變更權限，請至 設定 > 隱私權 > 定位服務 開啟", preferredStyle: .alert)
                let okAction = UIAlertAction(title: "ok", style: .default, handler: nil)
                alertController.addAction(okAction)
                self.present(alertController, animated: true, completion: nil)
            }//DispatchQueue
        }
    }//ViewDidLoad
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        if CLLocationManager.authorizationStatus() == .authorizedWhenInUse{
            myLocationManager.startUpdatingLocation()
    }//ViewDidAppear
    
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        myLocationManager.stopUpdatingLocation()
    }//viewDidDisappear
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }//didReceiveMemoryWarning   
    
    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == CLAuthorizationStatus.denied{
            let alertController = UIAlertController(title: "定位權限已關閉", message: "請至 設定 > 隱私權 > 定位服務 開啟定位功能", preferredStyle: .alert)
            let okAction = UIAlertAction(title: "ok", style: .default, handler: nil)
            alertController.addAction(okAction)
            self.present(alertController, animated: true, completion: nil)
        }//if
        else if status == CLAuthorizationStatus.authorizedWhenInUse{
            myLocationManager.startUpdatingLocation()
        }//else if
    }//func didChangeAuthorization
}//class