Delete contents of JSON object via table view controller - SWIFT - ios

Question

I am working on an iOS application which tracks user locations and 1) displays them as map annotation objects and 2) displays the data in a table view controller. The data contained in the table view controller is stored on the end user's iOS device as a JSON file. I am having an issue where I cannot get the records within the JSON file to delete even though delete has been enabled in the code for the table view controller.
I need another pair of eyes to look at the code and hopefully tell me what I'm missing.
The code consists of the following files:
MapViewController.swift
PlacesTableViewController.swift
Location.swift
LocationsStorage.swift
Extension to AppDelegate.swift (Only pertinent code included here)
The contents of the files are as follows:
MapViewController.swift *
import UIKit
import MapKit
class MapViewController: UIViewController {
#IBOutlet weak var mapView: MKMapView!
override func viewDidLoad() {
super.viewDidLoad()
mapView.userTrackingMode = .follow
let annotations = LocationsStorage.shared.locations.map { annotationForLocation($0) }
mapView.addAnnotations(annotations)
NotificationCenter.default.addObserver(self, selector: #selector(newLocationAdded(_:)), name: .newLocationSaved, object: nil)
}
#IBAction func addItemPressed(_ sender: Any) {
guard let currentLocation = mapView.userLocation.location else {
return
}
LocationsStorage.shared.saveCLLocationToDisk(currentLocation)
}
// Delete location pin from mapview
#IBAction func removeItemPressed(_ sender: Any) {
guard let currentLocation = mapView.userLocation.location else {
return
}
LocationsStorage.shared.saveCLLocationToDisk(currentLocation)
}
func annotationForLocation(_ location: Location) -> MKAnnotation {
let annotation = MKPointAnnotation()
annotation.title = location.dateString
annotation.coordinate = location.coordinates
return annotation
}
#objc func newLocationAdded(_ notification: Notification) {
guard let location = notification.userInfo?["location"] as? Location else {
return
}
let annotation = annotationForLocation(location)
mapView.addAnnotation(annotation)}}
PlacesTableViewController.swift *
import UIKit
import UserNotifications
class PlacesTableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(
self,
selector: #selector(newLocationAdded(_:)),
name: .newLocationSaved,
object: nil)
}
#objc func newLocationAdded(_ notification: Notification) {
tableView.reloadData()
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return LocationsStorage.shared.locations.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "PlaceCell", for: indexPath)
let location = LocationsStorage.shared.locations[indexPath.row]
cell.textLabel?.numberOfLines = 3
cell.textLabel?.text = location.description
cell.detailTextLabel?.text = location.dateString
return cell
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 110
}
// Enables swipe-to-delete functionality in table view.
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCell.EditingStyle.delete {
LocationsStorage.shared.locations.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: UITableView.RowAnimation.automatic)
tableView.reloadData()
}
}
}
Location.swift *
import Foundation
import CoreLocation
class Location: Codable {
static let dateFormatter: DateFormatter = {
let formatter = DateFormatter()
formatter.dateStyle = .medium
formatter.timeStyle = .medium
return formatter
}()
var coordinates: CLLocationCoordinate2D {
return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
}
let latitude: Double
let longitude: Double
let date: Date
let dateString: String
let description: String
init(_ location: CLLocationCoordinate2D, date: Date, descriptionString: String) {
latitude = location.latitude
longitude = location.longitude
self.date = date
dateString = Location.dateFormatter.string(from: date)
description = descriptionString
}
convenience init(visit: CLVisit, descriptionString: String) {
self.init(visit.coordinate, date: visit.arrivalDate, descriptionString: descriptionString)
}
}
LocationsStorage.swift *
import Foundation
import CoreLocation
class LocationsStorage {
static let shared = LocationsStorage()
//private(set) var locations: [Location]
var locations: [Location]
let fileManager: FileManager
// documentsURL cannot be private expression.
let documentsURL: URL
init() {
let fileManager = FileManager.default
// Location JSON file is stored in user's home directory on iOS. Inaccessible to PC/Mac hardware but can be accessed by application.
documentsURL = try! fileManager.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
self.fileManager = fileManager
let jsonDecoder = JSONDecoder()
let locationFilesURLs = try! fileManager.contentsOfDirectory(at: documentsURL,
includingPropertiesForKeys: nil)
locations = locationFilesURLs.compactMap { url -> Location? in
guard !url.absoluteString.contains(".DS_Store") else {
return nil
}
guard let data = try? Data(contentsOf: url) else {
return nil
}
return try? jsonDecoder.decode(Location.self, from: data)
}.sorted(by: { $0.date < $1.date })
}
// Saves location data to JSON object within user directory
func saveLocationOnDisk(_ location: Location) {
let encoder = JSONEncoder()
let timestamp = location.date.timeIntervalSince1970
let fileURL = documentsURL.appendingPathComponent("\(timestamp)")
let data = try! encoder.encode(location)
try! data.write(to: fileURL)
locations.append(location)
NotificationCenter.default.post(name: .newLocationSaved, object: self, userInfo: ["location": location])
}
func saveCLLocationToDisk(_ clLocation: CLLocation) {
let currentDate = Date()
AppDelegate.geoCoder.reverseGeocodeLocation(clLocation) { placemarks, _ in
if let place = placemarks?.first {
let location = Location(clLocation.coordinate, date: currentDate, descriptionString: "\(place)")
self.saveLocationOnDisk(location)
}
}
}
}
extension Notification.Name {
static let newLocationSaved = Notification.Name("newLocationSaved")
}
Extension to AppDelegate.swift *
// Journaling-specific variables
static let geoCoder = CLGeocoder()
let center = UNUserNotificationCenter.current()
let locationManager = CLLocationManager()
... [other code here, not related to question]
extension AppDelegate: CLLocationManagerDelegate {
func locationManager(_ manager: CLLocationManager, didVisit visit: CLVisit) {
// create CLLocation from the coordinates of CLVisit
let clLocation = CLLocation(latitude: visit.coordinate.latitude, longitude: visit.coordinate.longitude)
// Get location description
AppDelegate.geoCoder.reverseGeocodeLocation(clLocation) { placemarks, _ in
if let place = placemarks?.first {
let description = "\(place)"
self.newVisitReceived(visit, description: description)
}
}
}
func newVisitReceived(_ visit: CLVisit, description: String) {
let location = Location(visit: visit, descriptionString: description)
LocationsStorage.shared.saveLocationOnDisk(location)
let content = UNMutableNotificationContent()
content.title = "New Location Logged 📌"
content.body = location.description
content.sound = UNNotificationSound.default
// UNTimeIntervalNotificationTrigger is set to 10 minutes. User must spend 10 minutes at a location before a notificatin will be triggered and a log will be created.
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: (10*60), repeats: false)
let request = UNNotificationRequest(identifier: location.dateString, content: content, trigger: trigger)
center.add(request, withCompletionHandler: nil)
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.first else {
return
}
AppDelegate.geoCoder.reverseGeocodeLocation(location) { placemarks, _ in
if let place = placemarks?.first {
let description = "Fake visit: \(place)"
let fakeVisit = FakeVisit(coordinates: location.coordinate, arrivalDate: Date(), departureDate: Date())
self.newVisitReceived(fakeVisit, description: description)
}
}
}
}
final class FakeVisit: CLVisit {
private let myCoordinates: CLLocationCoordinate2D
private let myArrivalDate: Date
private let myDepartureDate: Date
override var coordinate: CLLocationCoordinate2D {
return myCoordinates
}
override var arrivalDate: Date {
return myArrivalDate
}
override var departureDate: Date {
return myDepartureDate
}
init(coordinates: CLLocationCoordinate2D, arrivalDate: Date, departureDate: Date) {
myCoordinates = coordinates
myArrivalDate = arrivalDate
myDepartureDate = departureDate
super.init()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Interestingly, when I am able to delete the records within the table view controller, they appear to delete until the next time the app launches, at which time they are back and still visible.
Any help would be appreciated.

Answer 1

As paulw11 stated in comments, needed to save JSON to disk after performing delete action.