List is not showing data from API in SwiftUI? - ios

Question

I am trying to get data from API and want to show that in List.
List {
ForEach(0 ..< (declarationViewModel.items?.count)!) { index in
HStack {
......
but as its taking some time to fetch data from API, initially data is 0 hence can not able to show data in list as it's not reloading after getting data.
public class DeclarationViewModel: ObservableObject {
#Published var items: [Item]?
#Published var title: String?
init() {
self.items = [Item]()
self.title = ""
}
init(items: [Item]?, title: String) {
self.items = items
self.title = title
}
}
Error log
forEach<Range<Int>, Int, HStack<TupleView<(HStack<TupleView<(ModifiedContent<ModifiedContent<Image, _EnvironmentKeyWritingModifier<Optional<Color>>>, _FrameLayout>, Text, Spacer)>>, Spacer, _ConditionalContent<ModifiedContent<ModifiedContent<Image, _EnvironmentKeyWritingModifier<Optional<Color>>>, _FrameLayout>, ModifiedContent<ModifiedContent<Image, _EnvironmentKeyWritingModifier<Optional<Color>>>, _FrameLayout>>, _ConditionalContent<ModifiedContent<ModifiedContent<Image, _EnvironmentKeyWritingModifier<Optional<Color>>>, _FrameLayout>, ModifiedContent<ModifiedContent<Image, _EnvironmentKeyWritingModifier<Optional<Color>>>, _FrameLayout>>)>>> count (14) != its initial count (0). `ForEach(_:content:)` should only be used for *constant* data. Instead conform data to `Identifiable` or use `ForEach(_:id:content:)` and provide an explicit `id`!

Answer 1

you could try something simple like this:
EDIT: and if your items are Identifiable, then remove the "id:.\self",
nothing to it.
List {
if let items = declarationViewModel.items {
ForEach(items, id: \.self) { item in
....
}
}
}

Answer 2

Check out your console, you'll see following warning:
ForEach<Range, Int, ModifiedContent<Text, AddGestureModifier<_EndedGesture>>> count (2) != its initial count (1). ForEach(_:content:) should only be used for constant data. Instead conform data to Identifiable or use ForEach(_:id:content:) and provide an explicit id!
Newer use 0..<shoppingList.count inside ForEach or List. At least use declarationViewModel.items.indices instead.
Make items non optional by specifying a default value of an empty array instead of initializing it in the init. You can do same with title:
#Published var items: [Item] = []
#Published var title = ""
But perfectly instead of using indices you need to confirm your Item to Identifiable and make sure each item has a unique id, so your animations will work good and SwiftUI reuse cells to increase performance. You can use UUID:
struct Item: Identifiable {
let id = UUID()
}
Then in ForEach you get item instead of index:
ForEach(declarationViewModel.items) { item in
If you also need index in ForEach, check out my ForEachIndexed in this answer