No images despite successful decoding of json data with SwiftUI - swift

Question

I have two pieces of code to decode json data (local and remote). Both work. I am also able to visualize my local data, however not the remote data. They are exactly the same (just the location of the json file and the imageUrl differs). In my TestView.swift code, which is used for both cases, I have given two comments that point to my problem.
My issue: How do I need to define testData:[Test] for the remote case, which is well defined for the local case?
What is missing? Please help. I am new to Xcode and SwiftUI so any help will be greatly appreciated.
P.S. Basically I am trying to build on two Swift Tutorials (on YouTube), i.e. Build a Complex UI with SwiftUI from Start to Finish, SwiftUI Fetching JSON and Image Data with BindableObject.
// Data.swift
import SwiftUI
import Combine
// 1.) This first piece of code decodes local json data and correctly visualize it
let testData:[Test] = load("test.json")
func load<T:Decodable>(_ filename:String, as type:T.Type = T.self) -> T {
let data:Data
guard let file = Bundle.main.url(forResource: filename, withExtension: nil)
else {
fatalError("Couldn't find \(filename) in main bundle.")
}
do {
data = try Data(contentsOf: file)
} catch {
fatalError("Couldn't load \(filename) from main bundle:\n\(error)")
}
do {
let decoder = JSONDecoder()
return try decoder.decode(T.self, from: data)
} catch {
fatalError("Couldn't parse \(filename) as \(T.self):\n\(error)")
}
}
struct Test_Previews: PreviewProvider {
static var previews: some View {
TestView()
}
}
// 2.) This 2nd piece of code decodes remote json data but does not visualize it
class testDatas: ObservableObject {
#Published var tests:[Test] = [Test]()
func getAllTests() {
let file = URLRequest(url: URL(string: "https://myurl/test.json")!)
let task = URLSession.shared.dataTask(with: file) { (data, _, error) in
guard error == nil else { return }
do {
let tests = try JSONDecoder().decode([Test].self, from: data!)
DispatchQueue.main.async {
self.tests = tests
print(tests)
}
} catch {
print("Failed To decode: ", error)
}
}
task.resume()
}
init() {
getAllTests()
}
init(tests: [Test]) {
self.tests = tests
}
}
struct Test_Previews: PreviewProvider {
static var previews: some View {
TestView()
}
}
// TestView.swift (used for both decode cases)
import SwiftUI
// testData needed here only for the remote case, but this might be wrong and the problem?
let testData:[Test] = [Test]()
struct TestView: View {
// testDatas needed here only for the remote case to decode json data)
#ObservedObject var fixer: testDatas = testDatas()
#EnvironmentObject var loader: ImageLoader
var categories:[String:[Test]] {
.init(
grouping: testData,
by: {$0.category.rawValue}
)
}
var body: some View {
NavigationView{
List (categories.keys.sorted(), id: \String.self) {key in TestRow(categoryName: "\(key).environmentObject(ImageLoader(with: key.imageUrl)) Tests".uppercased(), tests: self.categories[key]!)
.frame(height: 320)
.padding(.top)
.padding(.bottom)
}
.navigationBarTitle(Text("TEST"))
}
}
}
class ImageLoader:ObservableObject
{
#Published var data:Data = Data()
func getImage(imageURL:String) {
guard let test = URL(string: imageURL) else { return }
URLSession.shared.dataTask(with: test) { (data, response, error) in
DispatchQueue.main.async {
if let data = data {
self.data = data
}
}
print(data as Any)
}.resume()
}
init(imageURL:String) {
getImage(imageURL: imageURL)
}
}
struct TestView_Previews: PreviewProvider {
#ObservedObject var imageLoader: ImageLoader
init(test:String)
{
imageLoader = ImageLoader(imageURL: test)
}
static var previews: some View {
TestView()
}
}

Answer 1

With some help of #Josh Homann on a related question, I could solve my problem. All I had to do is to replace "grouping: testData" with "grouping: networkManager.tests" and by using "#ObservedObject var networkManager: NetworkManager = NetworkManager()". This makes the definition of testData redundant.