optional type String? not unwrapped - json

Question

I have a PHP page that is on my webserver that interacts with a mysql database called grabmapinfo.php
The output of the page is [{"companyname":"Brunos Burgers","companyphone":"7745632382","companytown":"858 Western Ave, Lynn, MA 01905"}]
Now I have this Swift code, which I want to get the info from the database, geocode the address to latitude and longitude, plot the annotation on the map, change the annotation image and title, and make a circle with a radius of 5 with the pin being in the center.
let locationManager = CLLocationManager()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.locationManager.delegate = self
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
self.locationManager.requestWhenInUseAuthorization()
self.locationManager.startUpdatingLocation()
self.buyerMapView1.showsUserLocation = true
let url = NSURL(string: "https://alanr917.000webhostapp.com/grabmapinfo.php")
var request = URLRequest(url:url! as URL)
URLSession.shared.dataTask(with: request as URLRequest, completionHandler: { (data:Data?, response:URLResponse?, error:Error?) -> Void in
if error != nil {
// Display an alert message
print(error)
return
}
do {
if let json = try JSONSerialization.jsonObject(with: data!, options: []) as? [[String:AnyObject]] {
for item in json {
// Get company info from DB
let companyname = item["companyname"] as? String
let companyphone = item["companyphone"] as? String
let companytown = item["companytown"] as? String
print("Company : \(companyname)")
print("Phone : \(companyphone)")
print("Address : \(companytown)")
let address = companytown
let geocoder = CLGeocoder()
geocoder.geocodeAddressString(address, completionHandler: {
(placemarks: [AnyObject]!, error: NSError!) -> Void in
if let placemark = placemarks?[0] as? CLPlacemark {
let pa = MKPointAnnotation()
pa.coordinate = placemark.location.coordinate
pa.title = companyname
pa.imageName = #imageLiteral(resourceName: "growerAnnotation")
self.buyerMapView1.addAnnotation(pa)
let center = annotation.coordinate
let circle = MKCircle(center: center, radius: 5) // change the 5 later to however many miles the grower purchased
self.buyerMapView1.add(circle)
}
})
}
}
} catch {
print(error)
}
})
}
But i get an error that says the optional type String? is not unwrapped and it errors out and wont build.
Does anyone see where I'm going wrong? Thanks!

Answer 1

companyTown is declared as an optional string and the geocodeAddressString method takes a string. You need to unwrap the option before calling it.
if let addressUnwrapped = address {
geocoder.geocodeAddressString(addressUnwrapped, completionHandler: {
(placemarks: [AnyObject]!, error: NSError!) -> Void in
...
})
}

Answer 2

Please check the comments through the code for more detailed explanation on the problems that I found in your code:
import UIKit
import CoreLocation
import MapKit
class ViewController: UIViewController, CLLocationManagerDelegate {
#IBOutlet weak var buyerMapView1: MKMapView!
let locationManager = CLLocationManager()
override func viewDidLoad() {
super.viewDidLoad()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.requestWhenInUseAuthorization()
locationManager.startUpdatingLocation()
buyerMapView1.showsUserLocation = true
// first unwrap your url
guard let url = URL(string: "https://alanr917.000webhostapp.com/grabmapinfo.php") else { return }
print("url:",url)
// no need to create a request. just a url is fine and you don't need to specify the parameters type. Let the compiler infer it.
URLSession.shared.dataTask(with: url) { data, response, error in
// unwrap your data and make sure there is no error
guard let data = data, error == nil else {
print(error ?? "nil")
return
}
// you should update the UI from the main queue
DispatchQueue.main.async {
print("data:", data)
do {
if let array = try JSONSerialization.jsonObject(with: data) as? [[String: Any]] {
for dict in array {
// make sure you unwrap your dictionary strings
let companyname = dict["companyname"] as? String ?? ""
let companyphone = dict["companyphone"] as? String ?? ""
let companytown = dict["companytown"] as? String ?? ""
print("Company:", companyname)
print("Phone:", companyphone)
print("Address:", companytown)
let address = companytown
let geocoder = CLGeocoder()
// again let the compiler infer the types vvv vvv
geocoder.geocodeAddressString(address) { placemarks, error in
if let placemark = placemarks?.first,
let coordinate = placemark.location?.coordinate {
let pa = MKPointAnnotation()
pa.coordinate = coordinate
pa.title = companyname
self.buyerMapView1.addAnnotation(pa)
let center = pa.coordinate // where does this coordinate come from??
let circle = MKCircle(center: center, radius: 5)
self.buyerMapView1.add(circle)
}
}
}
}
} catch {
print(error)
}
}
// you forgot to call resume to start your data task
}.resume()
}
}