SwiftUI Picker not changing selection value

Question

The following picker isn't updating $selection. Regardless of what the Picker shows while running the app, selection.rawValue always returns 0.

What is preventing the Picker from updating the State variable selection?

import SwiftUI struct OrderPicker: View { let initialIndex: Int @State private var selection: Index enum Index: Int, CaseIterable, Identifiable { case none = 0, first = 1, second = 2, third = 3 var id: Self { self } } init(initialIndex: Int) { self.initialIndex = initialIndex _selection = State(initialValue: OrderPicker.Index(rawValue: initialIndex) ?? .none) } var body: some View { Form { Picker("Order in list", selection: $selection) { ForEach(Index.allCases) { index in Text(String(describing: index)).tag(index) } } } .frame(height: 116) } func getOrderIndex() -> Int { let index = selection.rawValue return index } }

Your code is behaving as expected and is updating selection. You can verify this by adding .onChange(of: selection) { print($0) } to the end of your Form. However, the presence of getOrderIndex, which is unused in your current code, makes me wonder if you're trying to do something like reach into a child view to see it's state from the parent view or something like that. — jnpdx
– jnpdx, Commented Mar 18, 2022 at 3:36
You need to get rid of those initialization, no need to them, also need to use @Binding, and also using a style for picker as well. — swiftPunk
– swiftPunk, Commented Mar 18, 2022 at 3:41
@jnpdx You're correct, I am trying to read from selection in a parent class by exposing it with getOrderIndex. Will getOrderIndex not accurately return selection's rawValue? — Ryan Pierce
– Ryan Pierce, Commented Mar 18, 2022 at 4:00
You cannot reach into child views that way. Shared state should be stored in a parent view and passed down via Binding if necessary. — jnpdx
– jnpdx, Commented Mar 18, 2022 at 4:04

swiftPunk · Accepted Answer · 2022-03-18 03:52:02Z

Here is an approach for you:

struct ContentView: View { @State private var selection: PickerType = PickerType.none var body: some View { OrderPicker(selection: $selection) } } struct OrderPicker: View { @Binding var selection: PickerType var body: some View { Form { Picker("Order in list", selection: $selection) { ForEach(PickerType.allCases, id: \.self) { item in Text(item.rawValue) } } .pickerStyle(WheelPickerStyle()) .onChange(of: selection, perform: { newValue in print(newValue.rawValue, newValue.intValue) }) } } } enum PickerType: String, CaseIterable { case none, first, second, third var intValue: Int { switch self { case .none: return 0 case .first: return 1 case .second: return 2 case .third: return 3 } } }

Collectives™ on Stack Overflow

SwiftUI Picker not changing selection value

1 Answer 1

Comments

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Related