Retrieving coordinates from address retuning zero - swift

Question

I'm trying to play with SwiftUI and make a map with dropped pins from locations (generated from a database API).
I have my struct:
struct Locations: Decodable, Identifiable {
var id: Int { _id }
let _id: Int // the one used in the database
let streetaddress: String?
let suburb: String?
let state: String?
let postcode: String?
// get the co-ordinates now
var coordinates: CLLocationCoordinate2D? {
let geocoder = CLGeocoder()
var output = CLLocationCoordinate2D()
if let address = streetaddress,
let suburb = suburb,
let postcode = postcode,
let state = state {
let fullAddress = "\(address) \(suburb), \(state) \(postcode)"
geocoder.geocodeAddressString( String(fullAddress) ) { ( placemark, error ) in
if let latitude = placemark?.first?.location?.coordinate.latitude,
let longitude = placemark?.first?.location?.coordinate.longitude {
output = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
}
}
}
return output
}
}
However, whenever I call the coordinates I am getting a {"msg":"#NullIsland Received a latitude or longitude from getLocationForBundleID that was exactly zero", "latIsZero":0, "lonIsZero":0} error.
I have added the error snippet from here: https://stackoverflow.com/a/65837163/1086990 to dive deeper into the error, and it is returning network: network was unavailable or a network error occurred.
I am able to call Map() in the view, and permissions are set in the info.plist as well as see my current location, etc.
Is there something I'm missing or is it not calculating because the Strings are all optional? Been trying to understand how it's not generating the coordinates from the address.
If I try to debug in the view I tried this:
struct MapView: View {
var body: some View {
Text("Hello World")
.onAppear {
for l in modelData.locations {
print( String("\(l.coordinates)") )
}
}
}
}
// console
// Optional(__C.CLLocationCoordinate2D(latitude: 0.0, longitude: 0.0))
// ...
// Optional(__C.CLLocationCoordinate2D(latitude: 0.0, longitude: 0.0))

Answer 1

The issue there is that geocodeAddressString is an asynchronous method. You are returning the value before receiving the result. What you need is a method instead of a computed property and a completion handler.
func coordinate(completion: #escaping (CLLocationCoordinate2D?, Error?) -> Void) {
let streetAddress = streetAddress ?? ""
let suburb = suburb ?? ""
let postCode = postCode ?? ""
let state = state ?? ""
let fullAddress = "\(streetAddress) \(suburb), \(state) \(postCode)"
CLGeocoder().geocodeAddressString(fullAddress) { completion($0?.first?.location?.coordinate, $1) }
}
Usage:
#State var location = Location(id: 1, streetAddress: "One Infinite Loop", suburb: "Cupertino", state: "CA", postCode: "95014")
var body: some View {
Text("Hello, world!")
.padding()
.onAppear {
location.coordinate { coordinate, error in
guard let coordinate = coordinate else {
print("error:", error ?? "nil")
return
}
print("coordinate", coordinate)
}
}
}
This will print
coordinate CLLocationCoordinate2D(latitude: 37.331656, longitude: -122.0301426)

Answer 2

as mentioned geocodeAddressString is an asynchronous function. That means you have to use some completion handler. So you cannot use it like you do with coordinates.
Here is some very basic code using a function instead:
struct Locations: Decodable, Identifiable {
var id: String = UUID().uuidString
// let _id: Int // the one used in the database
let streetaddress: String? = "1 Infinite Loop"
let suburb: String? = "Cupertino"
let state: String? = "CA"
let postcode: String? = ""
func getCoordinates(handler: #escaping ((CLLocationCoordinate2D) -> Void)) {
if let address = streetaddress, let suburb = suburb, let postcode = postcode, let state = state {
let fullAddress = "\(address) \(suburb), \(state) \(postcode)"
CLGeocoder().geocodeAddressString(fullAddress) { ( placemark, error ) in
handler(placemark?.first?.location?.coordinate ?? CLLocationCoordinate2D())
}
}
}
}
struct ContentView: View {
let locs = Locations()
#State var coordString = ""
var body: some View {
Text(locs.streetaddress ?? "no address")
Text(coordString)
.onAppear {
locs.getCoordinates() { coords in
coordString = "\(coords.latitude), \(coords.longitude)"
}
}
}
}