How to pass data to a sub view from ContentView in SwiftUI - ios

Question

Forgive me if this doesn't make sense, I am a total beginner at Swift. I am creating a recipe app that pulls data from an API and lists it out in navigation links. When the user clicks on the recipe I want it to move to sub view and display information from the API such as recipe name, image, ingredients, and have a button with a link to the webpage.
I was able to get the data pulled into the list with navigation links. However, now I do not know how to go about setting up the recipe details sub view with all of the information I listed above.
This is where I call the API:
class RecipeService {
func getRecipes(_ completion: #escaping (Result<[Recipe], Error>) -> ()) {
let url = URL(string: "http://www.recipepuppy.com/api")!
URLSession.shared.dataTask(with: url) { (data, _, error) in
if let error = error {
return completion(.failure(error))
}
guard let data = data else {
return completion(.failure(NSError(domain: "", code: -1, userInfo: nil)))
}
do {
let response = try JSONDecoder().decode(RecipesResponses.self, from: data)
completion(.success(response.results))
} catch {
completion(.failure(error))
}
}.resume()
}
}
This is where I take in the recipe responses:
struct RecipesResponses: Codable {
let title: String
let version: Double
let href: String
let results: [Recipe]
}
struct Recipe: Codable {
let title, href, ingredients, thumbnail: String
var detail: URL {
URL(string: href)!
}
var thumb: URL {
URL(string: thumbnail)!
}
}
This is my recipe ViewModel:
class RecipeViewModel: ObservableObject {
#Published var recipes = [Recipe]()
#Published var isLoading = false
private let service = RecipeService()
init() {
loadData()
}
private func loadData() {
isLoading = true
service.getRecipes{ [weak self] result in
DispatchQueue.main.async {
self?.isLoading = false
switch result {
case .failure(let error):
print(error.localizedDescription)
case .success(let recipes):
self?.recipes = recipes
}
}
}
}
}
This is my view where I list out the API responses:
struct ListView: View {
#ObservedObject var viewModel = RecipeViewModel()
var body: some View {
NavigationView {
List(viewModel.recipes, id: \.href) { recipe in
NavigationLink (destination: RecipeDetailView()) {
HStack{
CachedImageView(recipe.thumb)
.mask(Circle())
.frame(width: 80)
VStack(alignment: .leading) {
Text(recipe.title)
.font(.largeTitle)
.foregroundColor(.black)
.padding()
}
}
.buttonStyle(PlainButtonStyle())
}
}
.navigationBarTitle(Text("All Recipes"))
}
}
}
struct ListView_Previews: PreviewProvider {
static var previews: some View {
ListView()
}
}
This is the view where I would like to list out the recipe details and link to the webpage. This is where I am struggling to be able to pull the API data into:
struct RecipeDetailView: View {
#ObservedObject var viewModel = RecipeViewModel()
var body: some View {
Text("Detail View")
}
}
struct RecipeDetailView_Previews: PreviewProvider {
static var previews: some View {
RecipeDetailView()
}
}
Images of app

Answer 1

You can change RecipeDetailView to accept a Recipe as a parameter:
struct RecipeDetailView: View {
var recipe : Recipe
var body: some View {
Text(recipe.title)
Link("Webpage", destination: recipe.detail)
//etc
}
}
Then, in your NavigationLink, pass the Recipe to it:
NavigationLink(destination: RecipeDetailView(recipe: recipe)) {
One thing I'd warn you about is force unwrapping the URLs in Recipe using ! -- you should know that if you ever get an invalid/malformed URL, this style of unwrapping will crash the app.
Update, to show you what the preview might look like:
struct RecipeDetailView_Previews: PreviewProvider {
static var previews: some View {
RecipeDetailView(recipe: Recipe(title: "Recipe name", href: "https://google.com", ingredients: "Stuff", thumbnail: "https://linktoimage.com"))
}
}