CODEWITHSUNDEEP
iosswiftswiftui
Aaron Rotem
Aaron Rotem

Reputation: 356

UUID Changing Unexpectedly

I'm sure there is some trivial answer as to what I am doing wrong, but I have been stumped trying to resolve this for the past few days and really appreciate any help as I learn swift.

I have a list of Place objects where the unique id for each object is a UUID. I want to look up an item in the list of objects but the UUID's of the items are never the same, I get different results even in the same view. I can run the same loop back to back, shown in the ListView.swift snippet below, but get completely different UUIDs printed.

I added a print statement in the id: UUID: { return UUID } to see how many objects get created (there should be 3 as I create 3 Places) but when the button is clicked that line is executed 27 times.

Overall, I am trying to figure out why these Place objects are getting over and over again when I expect it to only execute once and create a list of 3 objects.

 //PlaceListView - Called from ContentView and loads a list of ItemViews  
 struct PlaceListView: View {
        let places: [Place]
        List {
            ForEach(self.places, id: \.id) { place in
                ItemView(place: place)
            }
    }


//ItemView.swift - Trying to print the UUIDs
struct PlaceRowView: View {
    @EnvironmentObject var modelData: ModelData
    var body: some View {
    Button(action: {
           for p in modelData.savedPlaces {
               print(p.id)
           }
     }
}

//Place.swift - Object where the ID is a UUID
struct Place: Codable, Identifiable {
     var id: UUID: {
          return UUID()
     }
}

// ModelData.swift - Instantiating the list of Places
final class ModelData: ObservableObject {
    @Published var savedPlaces: [Place] = load("data.json")  
}

//App.swift - Instantiating the modelData object    
@main
    struct travel_trackerApp: App {
        @StateObject private var modelData = ModelData()
        var body: some Scene {
            WindowGroup {
                ContentView().environmentObject(modelData)
            }
        }
    }

Upvotes: 0

Views: 774

Answers (1)

Gereon
Gereon

Reputation: 17844

This:

struct Place: Codable, Identifiable {
     var id: UUID: {
          return UUID()
     }
}

creates a new UUID every time the property is accessed. Change it to read

struct Place: Codable, Identifiable {
   let id = UUID()
}

so the id is assigned only once.

Upvotes: 3

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