Reloading UITableview on iOS

Question

So when I select an item from the tableview, it segues into another viewcontroller and its passes data through that, I have it set that I segue back into the parent view controller. however it loses that data from the tableview, I tried to re-run the method that loads it but that doesn't seem to work, ideas as to what I am missing? I try to re-run methods that I think will do the job, but I'm not sure.

var locationManager = CLLocationManager()
var point = PFGeoPoint(latitude: 0.0, longitude: 0.0)
var vList = [Details]()
@IBOutlet var vListTableView: UITableView!
@IBOutlet var map: MKMapView!




override func viewDidLoad() {
    super.viewDidLoad()
    locationManager.delegate = self
    locationManager.desiredAccuracy = kCLLocationAccuracyBest
    locationManager.requestAlwaysAuthorization()
    locationManager.startUpdatingLocation()

}



override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
    let cell = self.vListTableView.dequeueReusableCell(withIdentifier: "venueDetailCell",for: indexPath) as! DetailsTableViewCell

    cell.Distance.text = String(vList[indexPath.row].distance)
    cell.title.text = vList[indexPath.row].name

    return cell
}


func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return vList.count

}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    downloadDataFromDB(location: point)
    self.vListTableView.reloadData()
    locationManager.startUpdatingLocation()
}

override func prepare(for segue: UIStoryboardSegue, sender: AnyObject?) {
    if(segue.identifier == "vDetailToCommentList"){
        var selectedRowIndex = self.vListTableView.indexPathForSelectedRow
        let moveViewCont:CommentsViewController = segue.destination as! CommentsViewController
        moveViewCont.Test = "Data pass successful"
    }
}

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){

    let userLocation: CLLocation = locations[0]
    let latitude: CLLocationDegrees = userLocation.coordinate.latitude
    let longitude: CLLocationDegrees = userLocation.coordinate.longitude
    let latDelta: CLLocationDegrees = 0.05
    let lonDelta: CLLocationDegrees = 0.05
    let span: MKCoordinateSpan=MKCoordinateSpan(latitudeDelta: latDelta, longitudeDelta: lonDelta)
    let location: CLLocationCoordinate2D = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    let region: MKCoordinateRegion = MKCoordinateRegion(center: location, span: span)
    map.setRegion(region, animated: true)
    map.showsUserLocation = true
    point = PFGeoPoint(latitude:latitude, longitude:longitude)
    updateUserLocationinDB(location: point)
    downloadDataFromDB(location: point)
}




func updateUserLocationinDB(location: PFGeoPoint){
    let uAct = PFQuery(className:"uAct")
    uAct.whereKey("userId", equalTo:(PFUser.current()?.username)!)
    uAct.findObjectsInBackground(block: {(objects, error) in
        if error != nil{
            print(error)
        }else if let users = objects {
            if objects?.count>0{
                for objects in users{
                    objects["UserLocation"] = location
                    objects.saveInBackground()
                }
            }

        }

    })
}


func downloadDataFromDB(location: PFGeoPoint){
    locationManager.stopUpdatingLocation()
    vList.removeAll()
    let qHotSpots = PFQuery(className: "HotSpots")
    qHotSpots.whereKey("venueLocation", nearGeoPoint: location, withinMiles: 10)
    do{
        let qReply = try qHotSpots.findObjects()
        if qReply.count>10{

            for object in qReply{
                let curDetails:Details = Details()
                let name:String = object.object(forKey:"venue")! as! String
                let id:String = object.objectId!
                let distance:Double = 0.0
                curDetails.name = name
                print("vList size",self.vList.count)
            }

        }
        else if qReply.count == 0{

            //TODO =: Download from API

        }
    }
    catch{
        print(error)
    }
}

class Details {
var id:String = ""
var name:String = ""
var distance:Double = 0.0


func Details(iD: String,nam: String,dist: Double){

    self.id = iD
    self.name = nam
    self.distance = dist


}

Maybe I am missing something?

Here's what I have tried

Answer 1

After thinking about when I should update the vListTableView: UITableView! , it makes sense that it should be updated immediately after populating vList . So it makes enough sense to me that the self.vListTableView.reloadData() should be called at the end of downloadDataFromDB as such:

func downloadDataFromDB(location: PFGeoPoint){
locationManager.stopUpdatingLocation()
vList.removeAll()
let qHotSpots = PFQuery(className: "HotSpots")
qHotSpots.whereKey("venueLocation", nearGeoPoint: location, withinMiles: 10)
do{
    let qReply = try qHotSpots.findObjects()
    if qReply.count>10{

        for object in qReply{
            let curDetails:Details = Details()
            let name:String = object.object(forKey:"venue")! as! String
            let id:String = object.objectId!
            let distance:Double = 0.0
            curDetails.name = name
            //print("vList size",self.vList.count)
        }
      //THE FIX WAS HERE
      self.venueListTableView.reloadData()
    }
    else if qReply.count == 0{

        //TODO =: Download from API

    }
}
catch{
    print(error)
}

This way, reloaddata is always called at the end of downloadDataFromDB and it is never needed anywhere else.

Like clockwork.