SwiftUI - Navigate to view after retrieving data - swiftui

Question

So I'm retrieving data from FireStore. I'm retrieving the data successfully. When I tap my search button the first time the data is being downloaded and the new view is pushed. As a result, I get a blank view. But when I go back, hit search again, sure enough I can see my data being presented.
How can I make sure I first have the data I'm searching for THEN navigate to the new view? I've used #State variables etc. But nothing seems to be working. I am using the MVVM approach.
My ViewModel:
class SearchPostsViewModel: ObservableObject {
var post: [PostModel] = []
#State var searchCompleted: Bool = false
func searchPosts(completed: #escaping() -> Void, onError: #escaping(_ errorMessage: String) -> Void) {
isLoading = true
API.Post.searchHousesForSale(propertyStatus: propertyStatus, propertyType: propertyType, location: location, noOfBathrooms: noOfBathroomsValue, noOfBedrooms: noOfBedroomsValue, price: Int(price!)) { (post) in
self.post = post
print(self.post.count)
self.isLoading = false
self.searchCompleted.toggle()
}
}
}
The code that does work, but with the bug:
NavigationLink(destination: FilterSearchResults(searchViewModel: self.searchPostsViewModel)
.onAppear(perform: {
DispatchQueue.main.async {
self.createUserRequest()
}
})
)
{
Text("Search").modifier(UploadButtonModifier())
}

Answer 1

Try with the following modified view model
class SearchPostsViewModel: ObservableObject {
#Published var post: [PostModel] = [] // << make both published
#Published var searchCompleted: Bool = false
func searchPosts(completed: #escaping() -> Void, onError: #escaping(_ errorMessage: String) -> Void) {
isLoading = true
API.Post.searchHousesForSale(propertyStatus: propertyStatus, propertyType: propertyType, location: location, noOfBathrooms: noOfBathroomsValue, noOfBedrooms: noOfBedroomsValue, price: Int(price!)) { (post) in
DispatchQueue.main.async {
self.post = post // << update on main queue
print(self.post.count)
self.isLoading = false
self.searchCompleted.toggle()
}
}
}
}

Answer 2

You should look at the Apple documentation for #State and ObservableObject
https://developer.apple.com/documentation/combine/observableobject
https://developer.apple.com/documentation/swiftui/state
Your issue is with using an #State in a non-UI class/View.
It might help if you start with the Apple SwiftUI tutorials. So you understand the differences in with the wrappers and learn how it all connects.
https://developer.apple.com/tutorials/swiftui
Also, when you post questions make sure your code can be copied and pasted onto Xcode as-is so people can test it. You will get better feedback if other developers can see what is actually happening. As you progress it won't be as easy to see issues.