tableView data source empty in viewDidLoad() - Swift

Question

Below is my ViewController code. The println in GetRequest prints the correct data that it receives from the HTTP GET request. At this point, tableData has 10 key-value pair

Answer 1

Rearrange the orders of the method calls:

override func viewDidLoad() {
    super.viewDidLoad()
    self.tableView.delegate = self
    self.tableView.dataSource = self
    var apiInfo = GetWaitTimes()
    GetRequest(apiInfo.BorderCrossingApi+"?AccessCode="+apiInfo.AccessCode)
    tableView.reloadData()
}

Explanation: you set the delegate and dataSource before you GetRequest() so the dataSource won't be nil.

Answer 2

The problem is that GetRequest runs asynchronously. So you have to reloadData inside the completionHandler of dataTaskWithURL:

let task = session.dataTaskWithURL(url, completionHandler: {data, response, error -> Void in

    // do all of your existing stuff here

    dispatch_async(dispatch_get_main_queue()) {
        self.tableData = LatestWaitTimes
        self.tableView.reloadData()
    }
})
task.resume()

You can remove the reloadData from within viewDidLoad.

Answer 3

Try this it may help you

you can add a callback (for reload tablview) in GetRequest function and run the callback after parser json in completionHandler

Maybe When you set the delegate with tableview, tableData still be nil (waitting for http response)

this is my code .you can refer to

demand.loadDataFromServer(self.view, done: { () -> Void in
     self.demands = demand.getDemandDataList()
     dispatch_async(dispatch_get_main_queue(), { () -> Void in
         self.tableView.reloadData()
     })
})


func loadDataFromServer(view:UIView,done:(() -> Void)!){
    var request:HttpRequest = HttpRequest(view:view)
    request.GET(getDemandListURL, parameters: nil, success: { (dict) -> Void in
        self.demandLists = dict["data"] as NSMutableArray
        done()
        }, failed: { (dict) -> Void in

        }) { (error) -> Void in
    }
}