Why Does This Swiftui Picker Code Not Work

Why does this SwiftUI Picker code not work?

ForEach types inside Picker should be aligned with selection type.

Here is a corrected code that should work for you:

@State private var letter = ""
private let letters = ["Alpha", "Bravo", "Charlie"]

var body: some View {
    NavigationView {
        Form {
            Picker("Select a letter", selection: $letter) {
                ForEach(letters, id: \.self) { option in
                    Text(option)
                }
            }
            Text("Selected letter: \(letter)")
        }
        .navigationBarTitle("Main Menu")
    }
}

Why does binding to the Picker not work anymore in swiftui?

I found a way to simplify the code a bit without the need of operating on indicies and tags.

At first, make sure to conform your model to Identifiable protocol like this (this is actually a key part, as it enables SwiftUI to differentiate elements):

public enum EditScheduleMode: String, CaseIterable, Identifiable {
    case closeSchedule
    case openSchedule
    
    public var id: EditScheduleMode { self }
    
    var localizedTitle: String { ... }
}

Then you can declare viewModel like this:

public class EditScheduleViewModel: ObservableObject {
    @Published public var editScheduleMode = EditScheduleMode.closeSchedule
    public let modes = EditScheduleMode.allCases
}

and UI:

struct ModeSelectionView: View {
    private let elements: [EditScheduleMode]
    @Binding private var selectedElement: EditScheduleMode
    
    internal init?(elements: [EditScheduleMode],
                   selectedElement: Binding<EditScheduleMode>) {
        self.elements = elements
        _selectedElement = selectedElement
    }
    
    internal var body: some View {
        VStack {
            Picker("", selection: $selectedElement) {
                ForEach(elements) { element in
                    Text(element.localizedTitle)
                }
            }
            .pickerStyle(.segmented)
        }
    }
}

With all of those you can create a view like this:

ModeSelectionView(elements: viewModel.modes, selectedElement: $viewModel.editScheduleMode)

SwiftUI: Why doesn't picker display?

Likely an older video, if you set the pickerStyle to .wheel

Picker("How do you want to pay?", selection: $paymentType) {
    //Your code
}.pickerStyle(.wheel)

you will get that look. Right now it is likely a menu style. When you don't set the type Apple can pick which style to use.

SwiftUI Picker not displaying Options

I recently managed to resolve this problem.

Picker needs to be wrapped in a NavigationView before it will work in a form.

I was able to simply add a NavigationView to the top of my view and put the form inside it, and now the picker works perfectly.

var body: some View{
    NavigationView{
        Form{
            ....
            Picker()
            ....    
        }
    }
}

SwiftUI picker in Form not working properly

This happens with optionals quite a bit you just have to specify type

Change your tags to something like this

.tag(month as? Month)

.tag(category as? Category)

The types have to match exactly. month and category are non-optionals so they need to be cast to optionals since your @State is an optional

iOS 15 SwiftUI 3 Picker binding is not working after changing @State value

Seems like iOS 15 does not work like before to change the value of State var and send it as Binding to a Picker.

the issue is that the State var selectedCategory is sent to the Picker as Binding and when I try to change the value of selectedCategory var on appearing the view, the binding is not being updated and the Picker value does not change when you select a different category.

What I did is to change the selectedCategory value in the init function before initializing the Picker:

import SwiftUI

struct Category: Identifiable {
    let id: UUID = UUID()
    let name: String
}

let categories: [Category] = [
    Category(name: "Cat 1"),
    Category(name: "Cat 2"),
    Category(name: "Cat 3")
]

struct ContentView: View {
    
    @State private var selectedCategory = -1
    
    init() {
        self._selectedCategory = State(initialValue: 1)
    }
    
    var body: some View {
        NavigationView {
            Form {
                Section {
                    Picker("Category", selection: $selectedCategory) {
                        ForEach(0..<categories.count) {
                            Text(categories[$0].name)
                                .tag($0)
                        }
                    }
                }
            }
        }
    }
}

Why do I need to assign a value on the init?
this is because in my project I need to update a Core Data record and I send the record to the view as ObservedObject and to change the category I need to change selectedCategory to have the value of the Core Data record and not the default value, by changing the value in onAppear the Picker get broken and does not work anymore, so the best way to do this in iOS 15 is to set the value in the init function and not in onAppear.

Picker in Menu with Section and Label doesn't work

You can put multiple Pickers in a Menu, each with a subset of the available values, and they’ll all work as expected:

Menu {

    // First section, with values 0–2
    Picker(selection: $num) {
        ForEach(0..<3, id: \.self) { i in
            Text("Number: \(i)").tag(i)
        }
    } label: {
        EmptyView()
    }

    // Second section, with values 3–5
    Picker(selection: $num) {
        ForEach(3..<6, id: \.self) { i in
            Text("Number: \(i)").tag(i)
        }
    } label: {
        EmptyView()
    }

} label: {
    Text("selected Number = \(num)")
}

SwiftUI will even stick a separator between the Pickers automatically.

SwiftUI Picker not changing selection value

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
        }
    }
    
}

---

Related Topics