SwiftUI TextField Binding to a simple Model (non-class sturct)

Question

I have a simple struct, that is decodable / codable and hashable.

public struct Field: Codable, Hashable {
    let key: String
    enum CodingKeys: String, CodingKey {
        case key
    }
}

In my SwiftUI, I'm creating an array, where I want to add and remove and Bind to the Struct values. But I am getting errors, that Struct is not Binding.

let decodableJSON = """
{
    "key": ""
}
"""
let settableInit: Field = try! JSONDecoder().decode(Field.self, from: decodableJSON.data(using: .utf8)!)

struct Test_view: View {
    
    @State
    var settableFields: [Field] = [settableInit]
    
    var body: some View {
        ForEach(settableFields, id: \.key) { (settableField: Field) in 
             TextField("Key", text: settableField.key)
        }

But I get an error, that settableField is not Binding. I have tried adding the settableInit as an @ObservableObject to the main Swift View, but it still doesn't work.

Is there a way, to have the View bind to Struct properties, and have TextField change these properties? It feels like something so trivial, but for some reason undoable for me.

Thank you for any pointers!

since you are dealing with a JSON try an ObservableObject with a variable with a custom {get set} that read/writes to your JSON accordingly and at the end of set use objectWillChange.send() to refresh — lorem ipsum
– lorem ipsum, Commented Oct 31, 2021 at 13:45

Adrian · Accepted Answer · 2021-10-31 11:12:25Z

4

In Xcode13 you can use the new element binding syntax:

public struct Field: Codable, Hashable {
    var key: String
    enum CodingKeys: String, CodingKey {
        case key
    }
}

struct Demo: View {
    
    @State var settableFields: [Field] = [Field(key: "1"), Field(key: "2")]
    
    var body: some View {
        ForEach($settableFields, id: \.key) { $settableField in
            TextField("Key", text: $settableField.key)
        }
    }
}

In earlier versions of Xcode you could use the indices of the array:

struct Demo: View {
    
    @State var settableFields: [Field] = [Field(key: "1"), Field(key: "2")]
    
    var body: some View {
        ForEach(settableFields.indices, id: \.self) { index in
            TextField("Key", text: $settableFields[index].key)
        }
    }
}

edited Oct 31, 2021 at 11:12

answered Oct 31, 2021 at 11:00

Adrian

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1 Comment

norwegiandev Over a year ago

Thank you Adrian, that did the trick for me! Legend

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