import SwiftUI
struct User: Identifiable {
let id: Int
let name: String
}
protocol UserRepository {
func fetchUsers() async -> [User]
}
class MockUserRepository: UserRepository {
func fetchUsers() async -> [User] {
try? await Task.sleep(nanoseconds: 1_000_000_000) // 1 second delay
return [
User(id: 1, name: "Alice"),
User(id: 2, name: "Bob"),
User(id: 3, name: "Charlie")
]
}
}
struct UserListView: View {
@State private var users: [User] = []
@State private var isLoading = false
private let repository: UserRepository = MockUserRepository()
var body: some View {
NavigationView {
VStack {
if isLoading {
ProgressView("Loading...")
.padding()
} else {
List(users) { user in
Text(user.name)
}
}
Button("Refresh") {
Task {
await loadUsers()
}
}
.padding()
}
.navigationTitle("User List")
}
.task {
await loadUsers()
}
}
private func loadUsers() async {
isLoading = true
users = await repository.fetchUsers()
isLoading = false
}
}
struct UserListView_Previews: PreviewProvider {
static var previews: some View {
UserListView()
}
}We start by defining a simple User struct with an id and name. This lets SwiftUI identify each user uniquely in the list.
The UserRepository protocol declares a method fetchUsers() that returns users asynchronously. This hides the data source details from the UI.
MockUserRepository implements this protocol and simulates a network delay using Task.sleep. It returns a fixed list of users.
In UserListView, we use @State properties to hold the users and loading state. The repository is a constant instance of MockUserRepository.
The UI shows a ProgressView while loading, and a List of user names when done. The Refresh button triggers reloading.
We use Swift concurrency with async and await to fetch users without blocking the UI. The .task modifier loads users when the view appears.
This pattern cleanly separates data fetching logic from UI code, making it easier to maintain and test.
