Connect @State variables to a Codable struct

Question

Created Mar ’22

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I currently have lots of @State var's on my app that I'd like to place inside a struct Codable which in turn will form the Json Object necessary to send as payload in an API. (The API part is out of scope for this question).

My 'ask' is, how do I place variables like the 2 I have below, inside the codable struct so when selected a value from the user, those values will be saved in a Json object.

For example, I have 2 variables:

    @State var pregnant: Bool = false
    @State var household_size: Int = 1

How will I place these two variables above in the codable struct?

    struct Welcome: Codable {
        let household: Household
    }

    struct Household: Codable {
        var pregnant: String
        var household_size: Int

        enum CodingKeys: String, CodingKey {
            case pregnant
            case household_size
    }
}

Right now, I'm receiving an error when I try to

let eligibility = Welcome(household: Household(pregnant:  pregnant, household_size: household_size))

(Note the eligibility constant above are the values of the @State variable's in the App.)

Thank you!

Answered by wzebrowski in 706918022

I was able to do this with @Published.

class User: ObservableObject, Codable {
    enum CodingKeys: CodingKey {
        case disabled
    }

    init() { }

    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        disabled = try container.decode(Bool.self, forKey: .disabled)
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(disabled, forKey: .disabled)
    }

    @Published var disabled: Bool = false

}

Boost

Answer 1

Claude31 OP

Mar ’22

I never thought of it this way, but I don't think it's possible to do it directly as you wish.

@State are var inside some View, to allow for automatic update.

struct in JSON are plain struct.

So, I think you would have to manage the 2 in parallel: the state var and the var for the encoding… When a state var changes, recompute the coddle struct then save it as needed.

0

Answer 2

wzebrowski OP

Mar ’22

Accepted Answer

I was able to do this with @Published.

class User: ObservableObject, Codable {
    enum CodingKeys: CodingKey {
        case disabled
    }

    init() { }

    required init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        disabled = try container.decode(Bool.self, forKey: .disabled)
    }

    func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encode(disabled, forKey: .disabled)
    }

    @Published var disabled: Bool = false

}

0