Choosing CoreData Entities from form picker

by

As written you are not matching the types of the array the picker and the FetchResult. See the comments

import SwiftUI

@available(iOS 15.0, *)
struct LearnView: View {
    //This is optional Language
    @State private var selectedLanguage: Language?
    //I commented out variables that are not part of the reproducible body provided
    //@State private var selectedCategory: SubCategory?
    //@State private var selectedDate = Date()
    
    @Environment(\.managedObjectContext) private var viewContext
     //This is FetchedResults<Language>
    @FetchRequest(entity: Language.entity(), sortDescriptors: []) var languages: FetchedResults<Language>
    // @FetchRequest(entity: SubCategory.entity(), sortDescriptors: []) var subCategories: FetchedResults<SubCategory>
    
    var body: some View {
        NavigationView {
            ZStack {
                Form {
                    Section("Learning Schedule") {
                        Picker("Please choose a language", selection: $selectedLanguage) {
                            //Map is needed for a plain array of languages
                            //ForEach(languages.map{$0}, id: \.self) { language in
                            //This version works too
                            //The point is to go from FetchedResults<Language> to [Language]
                            ForEach(Array(languages), id: \.self) { language in
                                
                                Text(language.name ?? "Unknown")
                                //The casting is necessary to make it an optional since your @State is an optional
                                    .tag(language as? Language)
                            }
                        }
                        Text("You selected: \(selectedLanguage?.name ?? "Unknown")")
                    }
                }
            }
        }
    }
}

@available(iOS 15.0, *)
struct LearnView_Previews: PreviewProvider {
    static var previews: some View {
        LearnView().environment(\.managedObjectContext, PersistenceController.preview.container.viewContext)
    }
}

More Related Contents:

  1. SwiftUI View and @FetchRequest predicate with variable that can change
  2. Fetch data from CoreData for iOS 14 widget
  3. SwiftUI hierarchical Picker with dynamic data crashes [duplicate]
  4. Multi-Component Picker (UIPickerView) in SwiftUI
  5. How to make a SwiftUI List scroll automatically?
  6. SwiftUI: How to pop to Root view
  7. Deleting list elements from SwiftUI’s List
  8. Custom back button for NavigationView’s navigation bar in SwiftUI
  9. How to detect a tap gesture location in SwiftUI?
  10. SwiftUI – State change in UITextField causes the frameWidth to grow uncontrolled and ignore bounds/frame
  11. Using NavigationLink in Menu (SwiftUI)
  12. SwiftUI: Forcing an Update
  13. How do you use .enumerated() with ForEach in SwiftUI?
  14. SwiftUI picker separate texts for selected item and selection view
  15. ‘Fatal error: index out of range’ when deleting bound object in view
  16. Programmatically detect Tab Bar or TabView height in SwiftUI
  17. SwiftUI: Pop to root view when selected tab is tapped again
  18. Deletable Table with TextField on SwiftUI
  19. SwiftUI Drag and Drop files
  20. How to use a @FetchRequest with the new searchable modifier in SwiftUI?
  21. Is SwiftUI backwards-compatible with iOS 12.x and older?
  22. How to access NSWindow from @main App using only SwiftUI?
  23. Setting the TimelineProvider refresh interval for Widget
  24. What is the real benefit of using Raycast in ARKit and RealityKit?
  25. Thread 1: EXC_BAD_INSTRUCTION when fetching data
  26. Conditionally use view in SwiftUI
  27. What is Content in SwiftUI?
  28. Programmatically navigate to new view in SwiftUI
  29. URLSession.shared.dataTaskPublisher not working on IOS 13.3
  30. Highlight a specific part of the text in SwiftUI

Leave a Comment