self.tableView.reloadData() not working in Swift

Question

I'm attempting to learn Swift & the basics of iOS dev at the same time, so bear with me. I've got a TableViewController that is firstly parsing a local JSON file and rendering it's very simple data into TableViewCell and SectionHeaderViews. Within the same TableViewController, I'm making a call to a JSON endpoint, which is returning data, which I am then setting to variables so I can access what I actually want to get at (the API structure is less than desirable). So, I finally set the proper data to be self.tableData and then call self.tableView.reloadData() but nothing happens. What gives?

import UIKit  class BusinessTableViewController: UITableViewController {      var data: NSMutableData = NSMutableData()     var tableData: NSArray = NSArray()      @lazy var Business: NSArray = {         let pathTCT = NSBundle.mainBundle().pathForResource("TCT", ofType: "json")         let data = NSData.dataWithContentsOfFile(pathTCT, options: nil, error: nil)         return NSJSONSerialization.JSONObjectWithData(data, options: nil, error: nil) as NSArray         }()      override func viewDidLoad() {         super.viewDidLoad()          navigationItem.titleView = UIImageView(image: UIImage(named: "growler"))          tableView.registerClass(BeerTableViewCell.self, forCellReuseIdentifier: "cell")         tableView.separatorStyle = .None          fetchKimono()     }      override func numberOfSectionsInTableView(tableView: UITableView!) -> Int { //        return Business.count         return 1     }      override func tableView(tableView: UITableView?, numberOfRowsInSection section: Int) -> Int {         let biz = Business[section] as NSDictionary         let results = biz["results"] as NSDictionary         let beers = results["collection1"] as NSArray         return beers.count     }      override func tableView(tableView: UITableView?, cellForRowAtIndexPath indexPath: NSIndexPath?) -> UITableViewCell? {         let cell = tableView!.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath!) as BeerTableViewCell         if let path = indexPath {             let biz = Business[path.section] as NSDictionary             let results = biz["results"] as NSDictionary             let beers = results["collection1"] as NSArray             let beer = beers[path.row] as NSDictionary              cell.titleLabel.text = beer["BeerName"] as String         }          return cell     }      override func tableView(tableView: UITableView!, titleForHeaderInSection section: Int) -> String! {         let biz = Business[section] as NSDictionary         return biz["name"] as String     }      override func tableView(tableView: UITableView!, viewForHeaderInSection section: Int) -> UIView! {         let biz = Business[section] as NSDictionary         let view = LocationHeaderView()         view.titleLabel.text = (biz["name"] as String).uppercaseString         return view     }      override func tableView(tableView: UITableView!, heightForHeaderInSection section: Int) -> CGFloat {         return 45     }      func fetchKimono() {         var urlPath = "names have been changed to protect the innocent"         var url: NSURL = NSURL(string: urlPath)         var request: NSURLRequest = NSURLRequest(URL: url)         var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)          connection.start()     }      func connection(didReceiveResponse: NSURLConnection!, didReceiveResponse response: NSURLResponse!) {         // Recieved a new request, clear out the data object         self.data = NSMutableData()     }      func connection(connection: NSURLConnection!, didReceiveData data: NSData!) {         // Append the recieved chunk of data to our data object         self.data.appendData(data)     }      func connectionDidFinishLoading(connection: NSURLConnection!) {         // Request complete, self.data should now hold the resulting info         // Convert the retrieved data in to an object through JSON deserialization         var err: NSError         var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options:    NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary         var results: NSDictionary = jsonResult["results"] as NSDictionary         var collection: NSArray = results["collection1"] as NSArray         if jsonResult.count>0 && collection.count>0 {             var results: NSArray = collection as NSArray             self.tableData = results             self.tableView.reloadData()         }     } } 

Answer 1

You'll need to reload the table on the UI thread via:

//swift 2.3 dispatch_async(dispatch_get_main_queue(), { () -> Void in     self.tableView.reloadData() })  //swift 5 DispatchQueue.main.async{     self.tableView.reloadData() } 

Follow up: An easier alternative to the connection.start() approach is to instead use NSURLConnection.sendAsynchronousRequest(...)

//NSOperationQueue.mainQueue() is the main thread NSURLConnection.sendAsynchronousRequest(NSURLRequest(URL: url), queue: NSOperationQueue.mainQueue()) { (response, data, error) -> Void in     //check error     var jsonError: NSError?     let json: AnyObject? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.allZeros, error: &jsonError)     //check jsonError     self.collectionView?.reloadData() } 

This doesn't allow you the flexibility of tracking the bytes though, for example you might want to calculate the progress of the download via bytesDownloaded/bytesNeeded