Blank Screen on Loading List in SwiftUI - swift

Question

I am trying to display a list in a view after a condition. If data is recieved from API than screen will load new view having list showing multiple fields. Here I am showing only one field in the list. The navigation code is working fine and data is also decoded however blank screen appears when clicking list button screen moves to next view but blank screen.
Here is the view in which I am showing list :
import SwiftUI
struct MyPriceList: View {
#StateObject var road = ListAPI()
List
{
ForEach(road.priceRoad)
{
road in
HStack{
Text(road.packageName)
.font(.system(size: 15))
.foregroundColor(.black)
}
}
}
}
struct MyPriceList_Previews: PreviewProvider {
static var previews: some View {
MyPriceList()
}
}
}
The following is the viewmodel in which I have decoded the JSON data and applied the navigation
import Foundation
class ListAPI : ObservableObject
{
#Published var priceRoad = [ResponseList]()
func getList()
{
// url building code //
let list = URLSession.shared.dataTask(with: urlRequest)
{
(data, response, error) in
if let error = error {
print("Error \(error)")
}
if let data = data
{
do
{
let jsonList = try JSONDecoder().decode(PriceList.self, from: data)
let panama = jsonList.response
for pan in panama
{
print(pan.packageName) //successfully printing
}
if jsonList.success==true
{
DispatchQueue.main.async
{
self.navigate = true
self.priceRoad = jsonList.response
}
}
else
{
DispatchQueue.main.async
{
self.errorMessage = jsonList.message
}
}
}
catch
{
print("error \(error)")
}
}
}
list.resume()
} }
This is the data model for Json
struct PriceList : Codable
{
let success: Bool
let message: String
let response: [ResponseList]
enum CodingKeys:String, CodingKey{
case response = "ResponseData"
case success = "IsSuccess"
case message = "Message"
}
}
struct ResponseList:Codable
{
let packageId: Int
let packageName: String
let price: Double
let discountedPrice: Double
let testType: String
let testPackageGroupId: Int?
let SampleType: [SampleTypeList]?
enum CodingKeys:String, CodingKey{
case packageId = "PackageId"
case packageName = "PackageName"
case price = "Price"
case discountedPrice = "DiscountedPrice"
case testType = "Type"
case testPackageGroupId = "TestPackageGroupId"
case SampleType = "SampleTypeList"
}}
struct SampleTypeList:Codable
{
let testSampleTypeId: String
let sampleName: String
let colourCode: String
enum CodingKeys:String, CodingKey{
case testSampleTypeId = "TestSampleTypeId"
case sampleName = "SampleName"
case colourCode = "ColourCode"
}
}
I need to display TestName as packageName, MRP as price, B2B as discountedPrice, and TestType as testType.

Answer 1

try this approach, calling road.getList() in .onAppear{}:
struct MyPriceList: View {
#StateObject var road = ListAPI()
var body: some View { // <-- here need a body
List
{
ForEach(road.priceRoad)
{
road in
HStack{
Text(road.packageName)
.font(.system(size: 15))
.foregroundColor(.black)
}
}
}
.onAppear {
road.getList() // <-- here load your data
}
}
}
and make PriceList and ResponseList Identifiable, like this:
struct PriceList : Identifiable, Codable {
let id = UUID()
// ...
}
struct ResponseList: Identifiable, Codable {
let id = UUID()
// ...
}
struct SampleTypeList: Identifiable, Codable {
let id = UUID()
// ...
}
Alternatively, in ListAPI, you could have init() { getList() }, instead of using .onAppear {road.getList()}