Firebase数据需要很长时间才能加载到TableView Swift 3中

Question

I have a tableview that loads data from Firebase, and on load it seems to take ages, around 10-15 seconds before any data is shown in the tableview. it also appears thet the app is frozen while this data is loading.

my function for getting the data is: this is called in viewDidLoad

  func getTrackData() {
    let result = FIRDatabase.database().reference(withPath: "tracks")
    result.observe(.value, with: { snapshot in
        var newItems: [newTracks] = []
        for item in snapshot.children {
            let trackDetails = newTracks(snapshot: item as! FIRDataSnapshot)
            newItems.append(trackDetails)
        }
        self.items = newItems
        self.items.sort(by: {$0.distance < $1.distance})
        self.tableView.reloadData()
    })

}

and my tableview is as follows:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    if let cell = tableView.dequeueReusableCell(withIdentifier: "TrackCell", for: indexPath) as? TrackCell {

        let tr: newTracks!
        if inSearchMode {
            tr = filteredTrack[indexPath.row]
            cell.configureCell(track: tr)
        } else {
            tr = items[indexPath.row]
            cell.configureCell(track: tr)
        }
        cell.configureCell(track: tr)

        cell.completion = {
            let coordinate = CLLocationCoordinate2DMake(tr.lat,tr.lon)
            let mapItem = MKMapItem(placemark: MKPlacemark(coordinate: coordinate,addressDictionary:nil))
            mapItem.name = tr.name
            mapItem.openInMaps(launchOptions: [MKLaunchOptionsDirectionsModeKey :MKLaunchOptionsDirectionsModeDriving])
            return()
        }

        cell.completion1 = {
            let url = URL(string: tr.link)!
            if #available(iOS 10.0, *) {
                UIApplication.shared.open(url, options: [:], completionHandler: nil)
            } else {
                UIApplication.shared.open(url)
            }
            return()
        }
        return cell
    } else {
        return UITableViewCell()
    }
}

My question is, is this code written ok, or is there a better way to do it. I have a concern that my function is getting each item and then reloading the tableview, and this may be slowing things down significantly. My data isnt massive, here is an example.

that shows 1 full record, there are 131 of those records in total.

Answer 1

Figured this out now, I had a calculation for distance in miles from current location being worked out with each set of data being loaded. This significantly slowed down the tableview population.

Just need to figure how to do this calculation now, but maybe after the data has loaded