A simple picker to pick a enum.

EnumPicker.swift

import SwiftUI

struct EnumPicker<T: Hashable & CaseIterable, V: View>: View {
    
    @Binding var selected: T
    var title: String? = nil
    
    let mapping: (T) -> V
    
    var body: some View {
        Picker(selection: $selected, label: Text(title ?? "")) {
            ForEach(Array(T.allCases), id: \.self) {
                mapping($0).tag($0)
            }
        }
    }
}

extension EnumPicker where T: RawRepresentable, T.RawValue == String, V == Text {
    init(selected: Binding<T>, title: String? = nil) {
        self.init(selected: selected, title: title) {
            Text($0.rawValue)
        }
    }
}

It is really simple to use if you have a case iterable enum with a raw value of String:

enum PickerAction: String, CaseIterable {
  case source, targets
}

Just simply:

struct ContentView: View {
    @State private var pickerAction = PickerAction.source
    var body: some View {
      EnumPicker(selected: $pickerAction)
    }
}

As it will produce a Text-view itself; but if your enum does not have such string as a raw value, you can return a view in a closure:

EnumPicker(selected: $pickerAction) { e in
  // return view here
}

and you can of course also change the picker style, just add it to the environment: (Thanks @tobiasdm)

var body: some View {
  EnumPicker(selected: $pickerAction)
    .pickerStyle(SegmentedPickerStyle())
}

PS: If you rely on a custom view instead of the string value, remember that SegmentedPickerStyle can only show one Image or one Text-view per segment.

It works great.

But in most cases, the raw values of the enums are not good enough to be displayed to the user and in some cases, we have Int as raw values. So I wrote another extension.

extension EnumPicker where T: Displayable, V == Text {
    init(selected: Binding<T>, title: String? = nil) {
        self.init(selected: selected, title: title) {
            Text($0.displayValue)
        }
    }
}

protocol Displayable {
    var displayValue: String { get }
}

This works great.

The only change I made is to use Apple's standard CustomStringConvertable protocol instead of Displayable.

extension EnumPicker where T: CustomStringConvertible, V == Text {
    
    init(_ title: String? = nil, selected: Binding<T>) {
        self.init(title: title, selected: selected) {
            Text($0.description)
        }
    }
}

Thanks @lstomberg!

And yes, it is always great to use things from the Swift Standard Library, good think 💪🏼💪🏼