In my app I am using Firebase db to store my data, I have everything working as it should, with my tableview populating with the data from the db. However I have found that on initial start it is quite slow to download the data, so I enable persistence in AppDelegate. When I did this and ran the app it crashes on load with an unexpectedly found nil error.
FIRDatabase.database().persistenceEnabled = true
is the line I added to AppDelegate under didFinishLaunching section.
The error occurs in this class on the line I have marked
import Foundation
import FirebaseDatabase
import CoreLocation
struct newTracks {
//Declerations
var locationManager = CLLocationManager()
let name: String!
let lat: Double!
let lon: Double!
let countryImage: String!
let link: String!
let ref: FIRDatabaseReference?
let distance: Double
//Initialize
init(name: String, trackId: Int, postcode: String, trackType: String, trackURL: String, locID: Int, lat: Double, lon: Double, phoneNumber: String, email: String, rating: Double, numrating: Double, totalrating: Double, countryImage: String, link: String, distance: Double) {
self.name = name
self.ref = nil
self.lat = lat
self.lon = lon
self.countryImage = countryImage
self.link = link
self.distance = distance
}
//Initialize data from Firebase
init(snapshot: FIRDataSnapshot) {
let snapshotValue = snapshot.value as! [String: AnyObject]
name = snapshotValue["name"] as! String
lat = snapshotValue["lat"]as! Double
lon = snapshotValue["long"]as! Double
ref = snapshot.ref
countryImage = snapshotValue["country"] as! String <-- Unexpectedly found nil
link = snapshotValue["link"] as! String
let currentLat = self.locationManager.location!.coordinate.latitude
let currentLon = self.locationManager.location!.coordinate.longitude
let myLocation = CLLocation(latitude: currentLat, longitude: currentLon)
let loc = CLLocation(latitude: lat, longitude: lon)
let distanceInMiles = round(myLocation.distance(from: loc) / 1609.34)
distance = distanceInMiles
}
func toAnyObject() -> Any {
return [
"name": name,
"lat": lat,
"lon": lon,
"countryImage": countryImage,
"link": link,
"distance": distance
]
}
}
I don't get why this works ok when persistence isn't switched on, but when I enable it it crashes. Any help is much appreciated.
You have marked countryImage as Optional value. Your snapshot may not have value for "country".
Try to change:
let countryImage: String!
to:
let countryImage: String
EDIT:
Maybe, when you are turning persistance on, your application is taking old data from cache. And this data doesn't have ["country"] in snapshot value. So it founds nil -> throwing error. Check your snapshotValue through breakpoint. And check if it has value for country
Hope it helps
I have resolved this by uninstalling the app from my phone, this cleared away the old cached data, seems to load ok now
Related
I am having trouble with working over data I receive from server.
Each time server sends data it is new coordinates for each user. I am looping over each incoming data, and I want to send the data in completion to receive them on other end. And update model class with them. At the moment I have two users in server. And sometimes the closure passes data two times, but sometimes just one. And interesting thing is that class properties are not updated, at least I dont see them on UI.
This is function I call when data is received. Response is just string I split to get user data.
func updateUserAdrress(response: String, completion: #escaping (Int, Double, Double, String) -> Void){
var data = response.components(separatedBy: "\n")
data.removeLast()
data.forEach { part in
let components = part.components(separatedBy: ",")
let userID = components[0].components(separatedBy: " ")
let id = Int(userID[1])
let latitude = Double(components[1])!
let longitude = Double(components[2])!
let location = CLLocation(latitude: latitude, longitude: longitude)
let geocoder = CLGeocoder()
geocoder.reverseGeocodeLocation(location) { (placemarks, error) in
if error == nil {
let placemark = placemarks?[0]
if let thoroughfare = placemark?.thoroughfare, let subThoroughfare = placemark?.subThoroughfare {
let collectedAddress = thoroughfare + " " + subThoroughfare
DispatchQueue.main.async {
completion(id!, latitude, longitude, collectedAddress)
}
}
} else {
print("Could not get address \(error!.localizedDescription)")
}
}
}
}
In this function I try to invoke the changes on objects. As the incoming data from server is different the first time I have splited the functionality, so the correct block of code would be called.
func collectUsers(_ response: String){
if users.count != 0{
updateUserAdrress(response: response) { id, latitude, longitude, address in
if let index = self.users.firstIndex(where: { $0.id == id }){
let user = self.users[index]
user.latitude = latitude
user.longitude = longitude
user.address = address
}
}
}else{
var userData = response.components(separatedBy: ";")
userData.removeLast()
let users = userData.compactMap { userString -> User? in
let userProperties = userString.components(separatedBy: ",")
var idPart = userProperties[0].components(separatedBy: " ")
if idPart.count == 2{
idPart.removeFirst()
}
guard userProperties.count == 5 else { return nil }
guard let id = Int(idPart[0]),
let latitude = Double(userProperties[3]),
let longitude = Double(userProperties[4]) else { return nil }
let collectedUser = User(id: id, name: userProperties[1], image: userProperties[2], latitude: latitude, longitude: longitude)
return collectedUser
}
DispatchQueue.main.async {
self.users = users
}
}
}
As I also need user address when app starts in model I have made simular function to call in init so it would get address for user. That seems to be working fine. But for more context I will add the model to.
class User: Identifiable {
var id: Int
let name: String
let image: String
var latitude: Double
var longitude: Double
var address: String = ""
init(id: Int, name: String, image: String, latitude: Double, longitude: Double){
self.id = id
self.name = name
self.image = image
self.latitude = latitude
self.longitude = longitude
getAddress(latitude: latitude, longitude: longitude) { address in
self.address = address
}
}
func getAddress(latitude: Double, longitude: Double, completion: #escaping (String) -> Void){
let location = CLLocation(latitude: latitude, longitude: longitude)
let geocoder = CLGeocoder()
geocoder.reverseGeocodeLocation(location) { (placemarks, error) in
if error == nil {
let placemark = placemarks?[0]
if let thoroughfare = placemark?.thoroughfare, let subThoroughfare = placemark?.subThoroughfare {
let collectedAddress = thoroughfare + " " + subThoroughfare
completion(collectedAddress)
}
} else {
print("Could not get address \(error!.localizedDescription)")
}
}
}
}
And one interesting thing. That when closure receives two times data and I assign them to class, there are no changes on UI.
I made this project on Xcode 13.4.1 because on Xcode 14 there is a bug on MapAnnotations throwing purple warnings on view changes.
I am working on a demo app to return a list of restaurant with the google places API.
I have a Restaurant class - 1 property is a custom type RestaurantDetails. This is where the challenge is:
Restaurant.swift
class Restaurant {
var id:String
var placeId:String
var name:String
var location: Location //Location + address + coordinate + distance
var phone:String?
let details : RestaurantDetails
init(id:String, placeId:String, name:String, location: Location, details: RestaurantDetails) {
self.id = id
self.placeId = placeId
self.name = name
self.location = location
self.details = details
}
convenience init(dict:[String:Any]) {
let id = dict["id"] as! String
let placeId = dict["place_id"] as! String
let name = dict["name"] as! String
let address = dict["formatted_address"] as? String
let location = Location(address: address!, json: dict["geometry"] as! [String : Any])
if let price = dict["price_level"] as? Double {
print("price => \(Price(valueDouble: price))")
}
if let rating = dict["rating"] as? Double {
print("rating => \(Rating(valueDouble: rating))")
}
self.init(id: id, placeId: placeId, name: name, location: location!, details: RestaurantDetails(json: dict)!)
}
}
the initialization of the details property fails each time
even using the breakpoint does not help to debug the error because the custom init? does not seem to fire. I do not see any syntax error though
I am usually using guard let control flow to parse the JSON format if the value exists. unsuccessful.
the breakpoint does not kick in on the RestaurantDetails.swift file
RestaurantDetails.swift
enum Price {
case cheap, expensive, `default`
init(valueDouble: Double) {
switch valueDouble {
case 0..<2: self = .cheap
case 2..<4 : self = .expensive
default: self = .default
}
}
var dollarSymbol : String {
switch self {
case .cheap: return "$"
case .expensive: return "$$"
default: return ""
}
}
}
enum Rating {
case low, fair, good, excellent, `default`
init(valueDouble: Double) {
switch valueDouble {
case 0..<2: self = .low
case 3..<4: self = .fair
case 4..<5: self = .good
case 6 : self = .excellent
default: self = .default
}
}
var starSymbol : String {
switch self {
case .low: return "⭐"
case .fair: return "⭐⭐"
case .good: return "⭐⭐⭐"
case .excellent: return "⭐⭐⭐⭐"
default: return ""
}
}
}
struct RestaurantDetails {
let price:Price
let rating:Rating // Rating (enum) (filter)
let openNow: Bool //(filter)
let types : [String]?
let photos : [NSDictionary]?
}
extension RestaurantDetails {
init?(json: [String: Any]) {
guard let price = json["price_level"] as? Double,
let rating = json["rating"] as? Double,
let openingHours = json["opening_hours"] as? NSDictionary,
let types = json["types"] as? [String],
let photos = json["photos"] as? [NSDictionary] else {
return nil
}
print("json details : \(json)")
self.price = Price(valueDouble: price)
self.rating = Rating(valueDouble: rating)
self.openNow = openingHours["open_now"] as! Bool != nil ?? false
self.types = types
self.photos = photos
}
}
I also have a Location.swift file that works perfectly
struct Location {
var address :String
var coordinate:(lat:Double, lng:Double)
}
extension Location {
init?(address: String, json:[String:Any]) {
guard let latitude = json["location"] as? NSDictionary, let longitude = json["location"] as? NSDictionary else { return nil }
self.init(address: address, coordinate: (lat: latitude["lat"] as! Double, lng: longitude["lng"] as! Double))
}
}
As vadian described in his comment, the issue causing the crash is that location has a failable initializer, you are forcibly unwrapping it, and since initialization is in fact failing, you have now force-unwrapped a nil value.
The broader questions are: what do you, the developer, want to happen when some or all location data is not available, and what is the best way to go about doing that?
Options for handling incomplete or missing location data
Based on your description of the problem (“a demo app to return a list of restaurant with the google places api”), it is not clear whether or not restaurants without useable location data should enter your model. It is also not clear whether or not there is some location data you could do without. So I see three options:
Discard all restaurants with incomplete location data
Discard some restaurants with incomplete location data while keeping others
Keep all restaurants regardless of location data
To implement these options, you may want to use some common tools for dealing with optionals:
Nil-coalescing operator
a = b ?? c
Set a equal to b, unless b is nil, in which case set a equal to c.
Optional binding in guard and if
guard let a = b else { return }
Set a equal to b unless b is nil, in which case return from the current context. You can do work in the else branch prior to returning.
if let a = b { /* Do work using a */ } else { /* Do other work */ }
If b is not nil, enter the if branch and set a equal to b; if b is nil, enter the else branch.
How to do it
Discard all restaurants with incomplete location data
In this case, you could make a failable initializer for Restaurant, guarded by location being non-nil:
/// Initialization fails if `location` is `nil`
convenience init?(id:String, placeId:String, name:String, location: Location?, details: RestaurantDetails) {
guard let location = location else { return nil }
self.init(id: id, placeId: placeId, name: name, location: location, details: details)
}
Discard some restaurants with incomplete location data while keeping others
You may be able to recover from some kinds of missing location data. For example, it may be the case that you really just need the street address string and the latitude and longitude are inessential. You could rewrite your Location struct to reflect that:
struct Location {
var address: String
var coordinate: (lat: Double, lng: Double)?
}
extension Location {
init?(address: String, json:[String:Any]) {
let coordinate: (Double, Double)?
if let latitude = json["location"] as? NSDictionary, let longitude = json["location"] as? NSDictionary {
coordinate = (latitude, longitude)
} else {
coordinate = nil
}
self.init(address: address, coordinate: coordinate)
}
}
Alternative, lat/long might be the important part, but it might sometimes be possible to recover them from the street address using another API:
struct Location {
var address: String
var coordinate: (lat: Double, lng: Double)
}
extension Location {
init?(address: String, json:[String:Any]) {
let coordinate: (Double, Double)?
if let latitude = json["location"] as? NSDictionary, let longitude = json["location"] as? NSDictionary {
coordinate = (latitude, longitude)
} else {
/* An API call that takes an address string and tries to return lat/long but might return nil */
coordinate = returnedCoordinateFromAPI
}
guard let coordinate = coordinate else { return nil }
self.init(address: address, coordinate: coordinate)
}
}
Keep all restaurants regardless of location data
This is the easiest case. If location is not essential, make it optional:
class Restaurant {
var id: String
var placeId: String
var name: String
var location: Location? //Location + address + coordinate + distance
var phone: String?
let details: RestaurantDetails
init(id:String, placeId:String, name:String, location: Location?, details: RestaurantDetails) {
self.id = id
self.placeId = placeId
self.name = name
self.location = location
self.details = details
}
convenience init?(dict:[String:Any]) {
guard let id = dict["id"] as? String,
let placeId = dict["place_id"] as? String,
let name = dict["name"] as? String else { return nil }
// Use the address from the dictionary unless it is nil, in which case substitute an empty string
let address = dict["formatted_address"] as? String ?? ""
let location = Location(address: address, json: dict["geometry"] as? [String : Any])
if let price = dict["price_level"] as? Double {
print("price => \(Price(valueDouble: price))")
}
if let rating = dict["rating"] as? Double {
print("rating => \(Rating(valueDouble: rating))")
}
guard let details = RestaurantDetails(json: dict) else { return nil }
self.init(id: id, placeId: placeId, name: name, location: location, details: details)
}
}
I am currently trying to get my data from firebase and create annotations in my MKMapKitView. I believe that I am retrieving the data properly but not creating the annotations properly.
I think that because there are multiple users I cannot just set it up as a regular way of annotating.
let userLocation = CLLocationCoordinate2D(latitude: Double(userLatitude!), longitude: Double(userLongitude!))
let userAnnotation = MKPointAnnotation();
userAnnotation.coordinate = self.userLocation!;
//userAnnotation.title = "Riders Location";
map.addAnnotation(userAnnotation);
}
I'll also add in how I am retrieving the users.
func retrieveUsers(){
let ref = Database.database().reference()
ref.child("users").queryOrderedByKey().observeSingleEvent(of: .value, with: { snapshot in
let users = snapshot.value as! [String: AnyObject]
self.user.removeAll()
for (_,value) in users {
if let uid = value["uid"] as? String {
if uid != Auth.auth().currentUser!.uid {
let userToShow = User()
if let fullName = value["full name"] as? String,
let userLongitude = value["long"] as? Double,
let userLatitude = value["lat"] as? Double
{
userToShow.fullName = value["full name"] as? String
userToShow.imagePath = value["urlToImage"] as? String
userToShow.userID = value["uid"] as? String
userToShow.userLongitude = value["long"] as? String
userToShow.userLatitude = value["lat"] as? String
self.user.append(userToShow)
}
}
}
}
DispatchQueue.main.async {
self.map.reloadInputViews()
//not sure if this is right
}
})
Thank you!!
It's a hunch, but I think you are after a function like this - you were pretty close with you effort! NB - no semicolons in swift syntax.
private func addUserAnnotation(user: User) {
let userAnnotation = MKPointAnnotation()
let userLocation = CLLocationCoordinate2D(latitude: Double(user.userLatitude!),
longitude: Double(user.userLongitude!))
userAnnotation.coordinate = userLocation
//userAnnotation.title = "Riders Location"
self.map.addAnnotation(userAnnotation)
}
Call the function like this - let's say you want to add annotation for just the first user from your user array:
addUserAnnotation(user: user[0]) //addUserAnnotation(user[0]) also acceptable
Here is the OP's class for the user. I think this is also important
class User: NSObject {
var userID: String!
var fullName: String!
var imagePath: String!
var userLongitude: Double! // change from String!
var userLatitude: Double! // change from String!
}
I am trying to add my locations values from firebase and turn them into annotation within my app. This is the code I have at the minute which is not working! Looking for a helping hand, feel like I am very close to getting this right but I have hit a mind block!
import UIKit
import Firebase
import MapKit
class ViewController: UIViewController {
#IBOutlet weak var mapView: MKMapView!
let locationsRef = FIRDatabase.database().reference(withPath: "locations")
override func viewDidLoad() {
super.viewDidLoad()
locationsRef.observe(.value, with: { snapshot in
for item in snapshot.children {
guard let locationData = item as? FIRDataSnapshot else { continue }
let locationValue = locationData.value as! [String: Any]
let location = CLLocationCoordinate2D(latitude: locationValue["lat"] as! Double, longitude: locationValue["lng"] as! Double)
let name = locationValue["name"] as! String
self.addAnnotation(at: location, name: name)
}
})
}
func addAnnotation(at location: CLLocationCoordinate2D, name: String) {
// add that annotation to the map
let annotation = MKPointAnnotation()
annotation.title = location["name"] as? String
annotation.coordinate = CLLocationCoordinate2D(latitude: location["latitude"] as! Double, longitude: location["lonitude"] as! Double)
mapView.addAnnotation(annotation)
}
}
My code is now working but I am getting this issue:
Could not cast value of type "NSTaggedPointerString' (0x10a708d10) to 'NSNumber' (0x109d10488).
Relating to this line of code:
let location = CLLocationCoordinate2D(latitude: locationValue["lat"] as! Double, longitude: locationValue["lng"] as! Double)
I have read something about converting a string to double but there is no string in this line? Can anybody help please?
Updated Code Subtitle
Subtitle
Update Error
Error
You are most likely storing the coordinates as String objects in your Firebase database. That's the most common reason that would cause that error. In that case, try the following
let lat = Double(locationValue["lat"] as! String)
let lng = Double(locationValue["lng"] as! String)
let location = CLLocationCoordinate2D(latitude: lat, longitude: lng)
Update
Some location entries of your database are stored as String objects, others as floating point numbers. You should have a consistent structure (i.e all of them be strings or doubles).
Either way, here's a solution for your error:
var location: CLLocationCoordinate2D!
if let lat = locationValue["lat"] as? String {
// stored as String
let lng = Double(locationValue["lng"] as! String)!
location = CLLocationCoordinate2D(latitude: Double(lat)!, longitude: lng)
}
else {
// stored as a floating point number
let lat = locationValue["lat"] as! Double
let lng = locationValue["lng"] as! Double
location = CLLocationCoordinate2D(latitude: lat, longitude: lng)
}
EDIT 2
Just remove the let here
I am loading some GeoData from my server and want to display them throw annotations:
Alamofire.request("http://localhost:1234/app/data").responseJSON { response in
switch response.result {
case .success(let value):
let json = JSON(value)
var annotations = [Station]()
for (key, subJson):(String, JSON) in json {
let lat: CLLocationDegrees = subJson["latitude"].double! as CLLocationDegrees
let long: CLLocationDegrees = subJson["longtitude"].double! as CLLocationDegrees
self.annotations += [Station(name: "test", lat: lat, long: long)]
}
DispatchQueue.main.async {
let allAnnotations = self.mapView.annotations
self.mapView.removeAnnotations(allAnnotations)
self.mapView.addAnnotations(annotations)
}
case .failure(let error):
print(error)
}
}
and my Station class:
class Station: NSObject, MKAnnotation {
var identifier = "test"
var title: String?
var coordinate: CLLocationCoordinate2D
init(name:String, lat:CLLocationDegrees, long:CLLocationDegrees) {
title = name
coordinate = CLLocationCoordinate2DMake(lat, long)
}
}
So what I did, is basically:
Load data from remote service and display these data as annotations on MKMapView.
But: somehow these annotations are not loaded on the map, even i first "remove" and next "add" them.
Any suggestions?
You're adding your Station instances to some self.annotations property, not your local variable, annotations. Thus, annotations local var is still just that empty array.
Obviously, you can fix that by referencing annotations rather than self.annotations:
var annotations = [Station]()
for (key, subJson): (String, JSON) in json {
let lat = ...
let long = ...
annotations += [Station(name: "test", lat: lat, long: long)] // not `self.annotations`
}
Or you can use map, avoiding this potential confusion altogether:
let annotations = json.map { key, subJson -> Station in
Station(name: "test", lat: subJson["latitude"].double!, long: subJson["longitude"].double!)
}