SwiftUI parse a json from an URL with entry values - json

Question

I'm stuck when a I need to load a json file to swiftUI when this json comes from an URL with entry variables that must be filled by the user before getting the data.
I have the following code:
// This is the structure to get the data from the API.
struct loka_result: Codable {
var date: String
var time: String
var unix_time: Int
var seqNumber : Int
var lat: Double
var lng: Double
var device: String
var accuracy: Double
var info: String
var temperature : Double?
var battery_voltage : Float?
}
// Now conform to Identifiable
extension loka_result: Identifiable {
public var id: Int { return unix_time }
}
// Model Data to get the data
final class ModelData: ObservableObject {
#Published var allthelokas : [loka_result] = loadAllData(deviceId:selected_loka, timeDelta: selected_delta)
}
// Function to get and parse the data
func loadAllData<T: Decodable>(deviceId:String,timeDelta:Int) -> T
{
let url = URL(string: "https://xxxx.php?device=\(deviceId)&hours=\(timeDelta)"),
data = try? Data(contentsOf: url!)
return
try! JSONDecoder().decode(T.self, from: data!)
}
Then in TempChartView I would like to get a list
import SwiftUI
struct TempChartNew: View {
#EnvironmentObject var modelData: ModelData
var body: some View {
VStack {
List(modelData.allthelokas) { j in
// ForEach(modelData.allthelokas) { jj in
HStack {
Text(j.device)
Text(j.date)
Text(j.time)
Text(String(j.seqNumber))
}
}
}
}
}
struct TempChartNew_Previews: PreviewProvider {
static var previews: some View {
TempChartNew().environmentObject(ModelData())
}
}
all this its working because just to test it I have added two global variables to fill in the data for the function.
var selected_loka: String = "3JJJ30"
var selected_delta: Int = 24
But the ideia would be for the view to have two entry points.
And its here where I'm stuck ! I don't know how to pass the variables to the class.
Does anyone can please point me in the correct direction ? - Thank you