Iterate through JSON array and add coordinates to the map - ios

Question

I'm using an API to get latitude and longitude coordinates and place them on a map with the name of the place it corresponds to. I'm able to put one place's lat and long coordinates but I'm not too sure how to add all of them to a map. I can't get my head around how to do it. I've tried to use a for loop to do it but I'm too sure on how I would implement it. This is what I've got so far:
func getData() {
let url = "https://www.givefood.org.uk/api/2/foodbanks/"
let task = URLSession.shared.dataTask(with: URL(string: url)!, completionHandler: { [self] data, response, error in
guard let data = data, error == nil else {
print("Wrong")
return
}
var result: [Info]?
do {
result = try JSONDecoder().decode([Info].self, from: data)
}
catch {
print("Failed to convert: \(error.localizedDescription)")
}
guard let json = result else {
return
}
for each in json {
var each = 0
each += 1
let comp = json[each].lat_lng?.components(separatedBy: ",")
let latString = comp![each]
let lonString = comp![each]
let lat = Double(latString)
let lon = Double(lonString)
let locationPin: CLLocationCoordinate2D = CLLocationCoordinate2DMake(lat!, lon!)
let location: CLLocationCoordinate2D = CLLocationCoordinate2DMake(51.55573, -0.108312)
let region = MKCoordinateRegion.init(center: location, latitudinalMeters: regionInMetres, longitudinalMeters: regionInMetres)
mapView.setRegion(region, animated: true)
let myAn1 = MapPin(title: json[each].name!, locationName: json[each].name!, coordinate: locationPin)
mapView.addAnnotations([myAn1])
}
})
task.resume()
}

Answer 1

Your loop is wrong, each after for is one Info item. The Int index each is pointless and you set it in each iteration to zero so you get always the same coordinate (at index 1).
First of all declare name and lat_lng as non-optional. All records contain both fields.
struct Info : Decodable {
let lat_lng : String
let name : String
}
Second of all for convenience reasons extend CLLocationCoordinate2D to create a coordinate from a string
extension CLLocationCoordinate2D {
init?(string: String) {
let comp = string.components(separatedBy: ",")
guard comp.count == 2, let lat = Double(comp[0]), let lon = Double(comp[1]) else { return nil }
self.init(latitude: lat, longitude: lon )
}
}
Third of all put all good code into the do scope instead of dealing with optionals and set the region once before the loop
func getData() {
let url = "https://www.givefood.org.uk/api/2/foodbanks/"
let task = URLSession.shared.dataTask(with: URL(string: url)!, completionHandler: { [self] data, response, error in
if let error = error { print(error); return }
do {
let result = try JSONDecoder().decode([Info].self, from: data!)
let location = CLLocationCoordinate2D(latitude: 51.55573, longitude: -0.108312)
let region = MKCoordinateRegion.init(center: location, latitudinalMeters: regionInMetres, longitudinalMeters: regionInMetres)
mapView.setRegion(region, animated: true)
var pins = [MapPin]()
for info in result {
if let coordinate = CLLocationCoordinate2D(string: info.lat_lng) {
pins.append(MapPin(title: info.name, locationName: info.name, coordinate: coordinate))
}
}
DispatchQueue.main.async {
self.mapView.addAnnotations(pins)
}
}
catch {
print("Failed to convert: \(error)")
}
})
task.resume()
}