JSON response not being shown inside the cell - ios

Question

I’m creating a Tableview and trying to include in the cell one information that I receive through a JSON from an API.
The information (JSON) is being received very well and recorded correctly inside the variable.
However, what I could find is that as the information is received with a small “delay” is not being set as the cell’s label text at the cell creation moment, which is being set with the default variable content.
I guess the solution would be to update the label at the moment I parse the JSON content, right? How do I do this? (Update a cell’s label after it is already created)
Any other insight/ solution is greatly appreciated.
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, AddStock {
let operacoesAcoes = ListaOperacoes()
var todasAsOperacoes : [Operacao] = []
#IBOutlet weak var acoesTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
acoesTableView.delegate = self
acoesTableView.dataSource = self
acoesTableView.register(UINib(nibName: "StandardStockListCell", bundle: nil), forCellReuseIdentifier: "standardCell")
operacoesAcoes.consolidaAcoes()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return operacoesAcoes.carteiraAcoes.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "standardCell", for: indexPath) as! StandardStockListCell
let informacaoCompletaAcao = operacoesAcoes.carteiraAcoes[indexPath.row]
cell.codigoTextField.text = informacaoCompletaAcao.codigoAcao
cell.nomeTextField.text = informacaoCompletaAcao.nomeAcao
cell.quantidadeTotal.text = String(informacaoCompletaAcao.quantidadeTotal)
cell.precoMedioLabel.text = String(format: "%.2f", informacaoCompletaAcao.precoMedio)
//
// This is the part of the code that should set one label with a value returned from "buscaCotacao" but it does not work
// because at the time the cell is displayed it is still not updated from JSON information:
// Note: the buscaCotacao func is working fine
cell.precoAtualLabel.text = buscaCotacao(ativo: informacaoCompletaAcao.codigoAcao)
return cell
}

Answer 1

You need to reload the table view on the main thread after receiving and parsing the JSON.
self.acoesTableView.reloadData()

Answer 2

I did some research and tryouts, and could figure out a very simple (and now obvious) solution to update my Label after the result of the request is received:
- I call the function which retrieves the information from an API to update the cell ("buscaCotacao"), including the [cell row] information
- I update the cell's label from inside the function, which will happen only after the reply is received:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "standardCell", for: indexPath) as! StandardStockListCell
let informacaoCompletaAcao = operacoesAcoes.carteiraAcoes[indexPath.row]
cell.codigoTextField.text = informacaoCompletaAcao.codigoAcao
cell.nomeTextField.text = informacaoCompletaAcao.nomeAcao
cell.quantidadeTotal.text = String(informacaoCompletaAcao.quantidadeTotal)
cell.precoMedioLabel.text = "R$ "+String(format: "%.2f", informacaoCompletaAcao.precoMedio)
buscaCotacao(ativo: informacaoCompletaAcao.codigoAcao, for: cell, indexPath: indexPath)
return cell
}
And in the function:
func buscaCotacao (ativo: String, for cell: StandardStockListCell, indexPath: IndexPath) {
let finalURL = "https://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&interval=1min&apikey=XXXXXXXXXXXXXX&outputsize=compact&symbol=" + ativo
Alamofire.request(finalURL, method: .get)
.responseJSON { response in
if response.result.isSuccess {
let resultadoJSON : JSON = JSON(response.result.value!)
let resultado = Float (self.parseResultado(json: resultadoJSON))!
cell.precoAtualLabel.text = "R$ "+String(format: "%.2f", resultado)
self.cotacoes[ativo] = resultado
} else {
cell.precoAtualLabel.text = "N/D"
print("Error: \(response.result.error!)")
}
}
}