ios - 如何将坐标从 didUpdateLocation 传送到某个 View Controller ？

Question

我正在尝试制作将传送 userCoordinate 的 LocationService 类，因此它可以被多个 View Controller 重用

import UIKit
import CoreLocation

class LocationService: NSObject {
    let manager = CLLocationManager()

    override init() {
        super.init()

        manager.delegate = self
        manager.desiredAccuracy = kCLLocationAccuracyBest
        manager.startUpdatingLocation()
    }

    func getPermission() {
        // to ask permission to the user by showing an alert (the alert message is available on info.plist)
        if CLLocationManager.authorizationStatus() == .notDetermined {
            manager.requestWhenInUseAuthorization()
        }
    }

    func checkLocationAuthorizationStatus() -> CLAuthorizationStatus{
        return CLLocationManager.authorizationStatus()
    }
}

extension LocationService : CLLocationManagerDelegate {

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == .authorizedWhenInUse {
            manager.requestLocation()
        }
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        print("location is not available: \(error.localizedDescription)")
    }

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

        guard let userLocation = locations.first else {return}

        if userLocation.horizontalAccuracy > 0 {
            manager.stopUpdatingLocation()

            let coordinate = Coordinate(location: userLocation)
            // how to convey this coordinate for several view controller?
        } 
    }
}

正如您在 CLLocationManagerDelegate 的 didUpdateLocations 方法中看到的那样，坐标需要一些时间才能生成。

但我不知道如何传达该用户坐标，我认为它将使用完成处理程序但我不知道如何获取它

假设在 HomeVC 中，我将调用 LocationService 来获取用户坐标

import UIKit

class HomeVC: UIViewController {

    let locationService = LocationService()

    override func viewDidLoad() {
        super.viewDidLoad()

        // get coordinate, something like this
       locationService.getCoordinate()
    }
}

Answer 1

您可以像 Paulw11 所说的那样使用 Notification。您需要更新 didUpdateLocations。这是您要发布通知的地方。

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

    guard let userLocation = locations.first else {return}

    if userLocation.horizontalAccuracy > 0 {
        manager.stopUpdatingLocation()

        let coordinate = Coordinate(location: userLocation)
        let locationDictionary: [String: Double] = ["lat": location.coordinate.latitude,
                                      "long": location.coordinate.longitude]
         NotificationCenter.default.post(name: NSNotification.Name(rawValue: "YourNotificationNameAsYouWantToNameIt"), object: nil, userInfo: locationDictionary)
    } 
}

现在在 viewDidLoad 中，在每个你想要这个位置的 View Controller 中，你需要观察这个通知:

NotificationCenter.default.addObserver(self, selector: #selector(doSomethingAboutLocation(_:)), name: NSNotification.Name(rawValue: "YourNotificationNameAsYouWantToNameIt"), object: nil)

然后在从选择器调用的函数中像这样访问您的位置:

@objc func doSomethingAboutLocation(_ notification: Notification) {
    if let notificationInfo = notification.userInfo {
       let coordinate = CLLocation(latitude: notificationInfo["lat"] as! Double, longitude: notificationInfo["long"] as! Double)
       // use your coordinate as you want
    }
}