I am working a on a project in swiftui, using swiftdata. I am new and having a hard time understanding how the modelcontext/container works with passing data between views. I have the same error showing up in each preview as well as in my @main App file.

The error reads: Missing argument for parameter ‘activity’ in call Insert ‘, activity: <#Binding#>

I have tried adding in activities and binding but then it usually says it is out of scope. I am probably doing most of this wrong but any help is appreciated.

@Model
final class Activity {
    var id: UUID
    var title: String
    var gear: [Gear]
    
    var theme: Theme
    
    // initialize with default values
    init(id: UUID = UUID(), title: String, gear: [String], theme: Theme) {
        self.id = id
        self.title = title
        self.gear = gear.map { Gear(name: $0)}
        self.theme = theme
    }
}

extension Activity {
    struct Gear: Identifiable, Codable {
        let id: UUID
        var name: String
        
        init(id: UUID = UUID(), name: String) {
            self.id = id
            self.name = name
        }
    }
    
    // create an empty activity
    static var emptyTrip: Activity {
        Activity(title: "", gear: [], theme: .red)
    }
}


extension Activity  {
  static let SampleData: [Activity] = [
    Activity(title: "Backpacking",
             gear: ["text", "text" text"], theme: .red),
    
    Activity(title: "Climbing",
             gear: ["text", "text" text"], theme: .red),
    
    Activity(title: "Day hik",
             gear: ["text", "text" text"], theme: .red)
  ]
}

import SwiftData
import SwiftUI

struct ActivityListView: View {
    @Environment(.modelContext) private var modelContext
    @Query(sort: Activity.title, order: .forward, animation: .default) private var activities: [Activity]
    @Binding var activity: Activity
    @State private var isPresentingNewActivityView = false
        
    var body: some View {
        NavigationStack {
            List {
                ForEach(activities) { activity in
                    NavigationLink {
                        ActivityDetailView(activity: $activity)
                    } label: {
                        CardView(trip: activity)
                    }
                    .listRowBackground(activity.theme.mainColor)
                    .swipeActions {
                      Button("Delete", role: .destructive) {
                        modelContext.delete(activity)
                      }
                    }
                }
            }
            .navigationTitle("Here's a title")
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button(action: {
                        isPresentingNewActivityView = true
                    }) {
                        Image(systemName: "plus")
                    }
                }
            }
            .overlay {
                if activities.isEmpty {
                    ContentUnavailableView("Some text goes right here." ,
                                           systemImage: "person",
                                           description: Text("Use the '+' to add some stuff."))
                }
            }
            
        }
        .sheet(isPresented: $isPresentingNewActivityView) {
            ActivityDetailView(activity: $activity )
        }
 
    }
    
}
#Preview {
    ActivityListView()
        .modelContainer(for: [Activity.self], inMemory:  true)
}