How to stop text cursor from jumping to the end in SwiftUI?

Question

I'm curious, has anyone seen this before, or do they know how to solve it? I have a situation where editing a textfield that's in a NavigationStack always pops the text cursor to the end of the field on every keystroke. I suspect it has something to do with SwiftUI's management of views and state, but I am not spotting anything unusual that I might be doing, other than the index lookup in the navigationDestination part. I don't understand why that would be a problem.

Here's some pretty minimal code demonstrating the problem (just try correcting the well-known Shakespeare quote):

struct CursorResetting: View {
    struct Record: Identifiable {
        var string = ""
        var id = UUID()
    }

    @State var path = NavigationPath()
    @State private var records = [
        Record(string: "To be and not to be"),
        Record(string: "That begs the question")
    ]

    var body: some View {
        NavigationStack(path: $path) {
            Form {
                List {
                    ForEach(records) { record in
                        NavigationLink(value: record.id) {
                            Text(record.string)
                        }
                    }
               }
            }
            .navigationDestination(for: UUID.self) { id in
                let index = records.firstIndex { $0.id == id }
                if let index {
                    Form {
                        TextField("Value", text: $records[index].string)
                    }
                } else {
                    Text("Invalid ID")
                }
            }
        }
    }
}

Answer 1

This is a known thing, and the reason why you can't use a Binding type with navigationDestination.

Binding triggers the View to redraw and it resets everything in the body including the navigationDestination modifier.

You have to use NavigationLink(destination:, label:)

import SwiftUI

struct CursorResettingView: View {
    struct Record: Identifiable {
        var string = ""
        var id = UUID()
    }
    
    @State var path = NavigationPath()
    @State private var records = [
        Record(string: "To be and not to be"),
        Record(string: "That begs the question")
    ]
    
    var body: some View {
        NavigationStack(path: $path) {
            Form {
                List {
                    ForEach($records) { $record in
                        NavigationLink {
                            Form {
                                TextField("Value", text: $record.string)
                            }
                        } label: {
                            Text(record.string)
                        }

                    }
                }
            }
            .navigationDestination(for: UUID.self) { id in
                //Use this for `View`s that don't use `Binding` type as argument.
            }
        }
    }
}
struct CursorResettingView_Previews: PreviewProvider {
    static var previews: some View {
        CursorResettingView()
    }
}

Anything that uses an array's index is generally considered unsafe with SwiftUI so "solutions" that depend on it will be inherently fragile.