For loop keeps iteratively parsing JSON even after condition is complete - ios

Question

I'm putting JSON data into a table view, and I'm trying to parse through the data using a for loop. However, when the loop is done parsing through the JSON data and has placed the 20 items into the table view, it restarts the process, parses the JSON again, and the same data appears in the table view again. This process repeats for a long time as well.
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
locationManager.delegate = self
locationManager.requestWhenInUseAuthorization()
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.startUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else{ return }
var searchURL = NSString(format: "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=%f,%f&radius=50000&types=night_club&key=MY_API_KEY", (location.coordinate.latitude),(location.coordinate.longitude)) as? String
var cityInfo = NSString(format: "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=%f,%f&radius=50000&types=locality&key=MY_API_KEY", (location.coordinate.latitude),(location.coordinate.longitude)) as? String
manager.stopUpdatingLocation()
getCityInfo(url: cityInfo!)
callAlamo(url: searchURL!)
}
func getCityInfo(url:String){
Alamofire.request(url).responseJSON(completionHandler: { response in
self.parseJSON(JSONData: response.data!)
})
}
func parseJSON(JSONData:Data){
do{
var readableJSON = try JSONSerialization.jsonObject(with: JSONData) as! JSONStandard
// PARSING THROUGH JSON DATA TO GET CITY NAME
if let results = readableJSON["results"] as? [JSONStandard]{
for i in 0..<results.count{
let item = results[i]
let cityInfo = item["name"] as! String
cityName.append(cityInfo)
// GETTING PHOTO URL WITH photo_reference AND PUTTING THEM INTO imageURL ARRAY
if let photos = item["photos"] as? [JSONStandard]{
for j in 0..<photos.count{
let photo = photos[j] as JSONStandard
let photoRef = photo["photo_reference"] as! String
let photoURL = NSString(format: "https://maps.googleapis.com/maps/api/place/photo?maxwidth=400&photoreference=%#&key=MY_API_KEY", photoRef) as? String
cityURL.append(photoURL!)
}
}
}
}
cityLabel.text = cityName[0]
cityImage.sd_setImage(with: URL(string:cityURL[0]), placeholderImage: #imageLiteral(resourceName: "cityOfCalgary"))
}
catch{
print(error)
}
}
func callAlamo(url:String){
Alamofire.request(url).responseJSON(completionHandler: { response in
self.parseData(JSONData: response.data!)
})
}
func parseData(JSONData:Data){
do{
var myReadableJSON = try JSONSerialization.jsonObject(with: JSONData, options: .mutableContainers) as! JSONStandard
// PARSING THROUGH JSON DATA TO GET NAMES AND PICTURES OF PLACES, THEN PUTTING
// THEM INTO AN ARRAY AND OUTPUTTING THEM ONTO TABLE VIEW CELL
if let results = myReadableJSON["results"] as? [JSONStandard]{
for i in 0..<results.count{ //results.count = 20
let item = results[i]
let names = item["name"] as! String
placeNames.append(names)
// GETTING PHOTO URL WITH photo_reference AND PUTTING THEM INTO imageURL ARRAY
if let photos = item["photos"] as? [JSONStandard]{
let photoRef = photos[0]
let photoReference = photoRef["photo_reference"] as! String
let photoURL = NSString(format: "https://maps.googleapis.com/maps/api/place/photo?maxwidth=400&photoreference=%#&key=MY_API_KEY", photoReference) as? String
imageURL.append(photoURL!)
}
if let geometry = item["geometry"] as? JSONStandard{
if let location = geometry["location"] as? [String : Any]{
let latitude = location["lat"] as? Double
let longitude = location["lng"] as? Double
}
}
}
}
// SHOULD BE PLACED AT THE END OF GATHERING DATA
locationManager.stopUpdatingLocation()
self.tableView.reloadData()
}
catch{
print(error)
}
}
UPDATE:
As vadian had mentioned in one of his first comments, parseData() was getting called multiple times. So I added
locationManager.delegate = nil
after I stop updating the location in the locationManager delegate function.
`
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else{ return }
searchURL = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=\(location.coordinate.latitude),\(location.coordinate.longitude)&radius=50000&types=night_club&key=MY_API_KEY"
cityInfo = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=\(location.coordinate.latitude),\(location.coordinate.longitude)&radius=50000&types=locality&key=MY_API_KEY"
locationManager.stopUpdatingLocation()
locationManager.delegate = nil
getCityInfo(url: cityInfo)
callAlamo(url: searchURL)
}
`
Everything else remains the same after this.

Answer 1

As I suspected you are calling parseData multiple times. A solution is to stop monitoring the location right in the delegate method.
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else { return }
let searchURL = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=\(location.coordinate.latitude),\(location.coordinate.longitude)&radius=50000&types=night_club&key=AIzaSyA2LQsGK_I1ETnKPGbjWgFW9onZlHog6dg"
// var cityInfo = NSString(format: "https://maps.googleapis.com/maps/api/place/nearbysearch/json?location=%f,%f&radius=50000&types=locality&key=AIzaSyA2LQsGK_I1ETnKPGbjWgFW9onZlHog6dg", (location?.coordinate.latitude)!,(location?.coordinate.longitude)!) as? String
manager.stopUpdatingLocation()
callAlamo(url: searchURL)
}
I edited the body of the method a bit to avoid all question and exclamation marks.
Side-note: Basically do not annotate types the compiler can infer.