swift - 如何使用Cloud Firestore中的geopoint设置tableview以将商店放置在离我当前位置最近的位置？

Question

我要尝试的是使用Cloud Firestore中的Geopoint按离当前位置最近的商店来组织我的单元

我已经查看了整个堆栈，但是找不到如何在ViewController中设置表格视图，以使用Cloud Firestore中的geopoint显示距当前位置最近的我的鲜花店

这就是我目前要设置的数据，以传递给VC，以便将数据从Firestore整理到距离我当前位置最近的商店

下面，我在Firestore中有一个集合的图像，还有一个关于我的应用程序设置方式的ViewController的图像

import Foundation
import UIKit

class Store {
    var id: String
    var storeName: String
    var imageUrl: String
    var location: ??

    init(id: String,
         storeName: String,
         imageUrl: String,
         location:??) {                                              //

        self.id = id
        self.storeName = storeName
        self.imageUrl = imageUrl
        self.location = location                                    //
    }

    convenience init(dictionary: [String : Any]) {
        let id = dictionary["id"] as? String ?? ""
        let storeName = dictionary["storeName"] as? String ?? ""
        let imageUrl =  dictionary["imageUrl"] as? String ?? ""
        let location =  dictionary["location"] as? String ?? ""    //

        self.init(id: id,
                  storeName: storeName,
                  imageUrl: imageUrl,
                  location: location)                              //
    }

}

import UIKit
import CoreLocation
import Firebase
import FirebaseFirestore

class ViewController: UIViewController, CLLocationManagerDelegate {

    var locationManager: CLLocationManager?

    @IBOutlet weak var tableView: UITableView!

    var stores: [Store] = []

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager = CLLocationManager()
        locationManager?.delegate = self
        locationManager?.requestWhenInUseAuthorization()

        tableView.dataSource = self
        tableView.delegate = self

        fetchStores { (stores) in
            self.stores = stores
            self.tableView.reloadData()
        }

    }

    func fetchStores(_ completion: @escaping ([Store]) -> Void) {
        let ref = Firestore.firestore().collection("storeName")
            ref.addSnapshotListener { (snapshot, error) in
            guard error == nil, let snapshot = snapshot, !snapshot.isEmpty else {
                return
            }
            completion(snapshot.documents.compactMap( {Store(dictionary: $0.data())} ))
        }
    }

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        if status == .authorizedWhenInUse {
            if CLLocationManager.isMonitoringAvailable(for: CLBeaconRegion.self){
                if CLLocationManager.isRangingAvailable() {
                    // do Stuff
                }
            }
        }
    }
}

Answer 1

我相信这个答案应该有用，尽管我可能已经错过了一些东西。

您要做的是将location属性设置为Store类型的CLLocationCoordinate2D。这需要导入CoreLocation。您还希望添加一个名为distanceFromUser的属性，该属性使用CLLocation.distance(from:)方法来查找用户当前位置与商店位置之间的距离（以米为单位）：

import Foundation
import UIKit
import CoreLocation
import Firebase
import FirebaseFirestore

class Store {
    var id: String
    var storeName: String
    var imageUrl: String
    var location: CLLocationCoordinate2D
    var distanceFromUser: Double

    init(id: String,
         storeName: String,
         imageUrl: String,
         location: CLLocationCoordinate2D) {

        self.id = id
        self.storeName = storeName
        self.imageUrl = imageUrl
        self.location = location  
        self.distanceFromUser = (CLLocationManager().location?.distance(from: CLLocation(latitude: location.latitude, longitude: location.longitude)))!
    }

    convenience init(dictionary: [String : Any]) {
        let id = dictionary["id"] as? String ?? ""
        let storeName = dictionary["storeName"] as? String ?? ""
        let imageUrl =  dictionary["imageUrl"] as? String ?? ""

        //We now have to convert Firestore's "location" property from a GeoPoint to a CLLocationCoordinate2d
        let geoPoint = dictionary["location"] as! GeoPoint
        let latitude = geoPoint.latitude
        let longitude = geoPoint.longitude

        let location =  CLLocationCoordinate2D(latitude: latitude!, longitude: longitude!)

        self.init(id: id,
                  storeName: storeName,
                  imageUrl: imageUrl,
                  location: location)
    }
}

然后，您需要在 distanceFromUser的 ViewController中按 viewDidLoad对商店进行排序：

import UIKit
import CoreLocation
import Firebase
import FirebaseFirestore

class ViewController: UIViewController, CLLocationManagerDelegate {

    ...

    override func viewDidLoad() {
        super.viewDidLoad()

        locationManager = CLLocationManager()
        locationManager?.delegate = self
        locationManager?.requestWhenInUseAuthorization()

        tableView.dataSource = self
        tableView.delegate = self

        fetchStores { (stores) in
            self.stores = stores.sorted(by: { $0.distanceFromUser < $1.distanceFromUser })
            self.tableView.reloadData()
        }

    }

    ...

}