SOLVED: Storing an enum using @SceneStorage

@appocalypse

Mar '22

I am trying to store the value of an enumeration using the @SceneStorage property wrapper.

It is a macOS app, and I am doing this because the sidebar of the app I am playing around with represents documents that may be grouped in Core Data by some group ID (like a folder ID), or they may be pseudo- or meta-groups of documents, such as "All" or "Recent". I would like my app to remember which document group is selected.

The enum looks like this:

enum DocumentGrouping {
    case all
    case recent
    case folder(UUID)
}

...and my @SceneStorage declaration looks like this:

@SceneStorage("selection") private var selectedDocumentGrouping: DocumentGrouping

However, Swift(UI) complains "No exact matches in call to initializer." How do I get around this?

Or, if this is not a good approach, how can I rework my sidebar's List(selection: $selectedDocumentGrouping) to best implement this?

Thanks! Mark

@roosterboy HWS+

Mar '22

Two things you need to do:

Assign a default value to your @SceneStorage:

@SceneStorage("selection") private var selectedDocumentGrouping = DocumentGrouping.all

Make DocumentGrouping conform to RawRepresentable so you can store the rawValue in @SceneStorage as a String.

extension DocumentGrouping: RawRepresentable {
    var rawValue: String {
        switch self {
        case .all: return "all"
        case .recent: return "recent"
        case let .folder(uuid): return uuid.uuidString
        }
    }

    init?(rawValue: String) {
        switch rawValue {
        case "all": self = .all
        case "recent": self = .recent
        case let uuidString:
            guard let uuid = UUID(uuidString: uuidString) else {
                return nil
            }
            self = .folder(uuid)
        }
    }
}

That should work.

@appocalypse

Mar '22

Awesome, that compiles although I won't know until tomorrow if it is functioning as expected.

I had just started going down the Codable route rather than the RawRepresentable one; so thank you!

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