fill in UITableViewCell with JSONdata - ios

Question

I am trying to display some json data inside my tableView cell, and parsed the json data.
But
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.contents.count
}
returning 0
and as a result, I cannot display the data inside the UITableViewCell eventhough I have all my JSON data have been parsed and ready to be displayed.. .
how to fix it?
my response Model class and the rest of implementation are as follows:
Model classes for json response
// MARK: - TradingPairElement
class TradingPair: Entity {
var id: Int?
//var name: String?
var quoteAsset: QuoteAsset?
}
enum QuoteAsset: String, Codable {
case btc = "BTC"
case krw = "KRW"
}
// MARK: - TickerByPair
class TickerByPair: Entity {
var ask: Int?
//var price: Double?
//var volume: Double?
var askVolume: Double?
var bid: Int?
var bidVolume: Double?
var time: String?
}
And a wrapper class for the above two class 's contents:
class Entity: Codable {
var name: String?
var price: Double?
var volume: Double?
}
and here is how i am getting the data from the api and assigning to my self variables:
func APIcall() {
ServerCommunicator.getPairs().done{ response -> Void in
for keyPathParam in response {
self.keyPathParam = keyPathParam.name
}
ServerCommunicator.getPair(with: self.keyPathParam).done{ ticker -> Void in
for data in self.contents {
data.name = ticker.name
data.price = ticker.price
data.volume = ticker.volume
self.contents.append(data)
}
}.catch{(err) in
print(err)
}
}.catch{(error) in
print(error)
}
}

Answer 1

First of all if the API sends always all keys declare the properties non-optional and as constants and most likely you don't need a class and conformance to Encodable
struct Entity: Decodable {
let name: String
let price: Double
let volume: Double
}
After getting the data from the server you have to create new instances of Entity and assign them to the data source array. Further you need DispatchGroup to handle the loop and reload the table view after the last entity has been created.
If you want to overwrite self.contents with the received data uncomment the removeAll line
func APIcall() {
ServerCommunicator.getPairs().done{ response in
// self.contents.removeAll()
let group = DispatchGroup()
for keyPathParam in response {
group.enter()
ServerCommunicator.getPair(with: keyPathParam.name).done{ ticker in
let entity = Entity(name: ticker.name, price: ticker.price, volume: ticker.volume)
self.contents.append(entity)
group.leave()
}.catch{(err) in
print(err)
group.leave()
}
}
group.notify(queue: .main) {
self.tableView.reloadData()
}
}.catch{(error) in
print(error)
}
}