SwiftUI - ObservableObject, EnvironmentObject, SummaryView - view

Question

After creating the code, i would like to create a summary view that allows me to view the values that have been chosen in the picker.
How can I do? I read some forums about #ObservableObject and about #EnvironmentObject, but I can't understand ...
Thanks very much :)
import SwiftUI
//SUMMARYPAGE
struct SummaryView: View {
var body: some View {
NavigationView {
Form {
VStack(alignment: .leading, spacing: 6) {
Text("First Animal: \("firstAnimalSelected")")
Text("First Animal: \("secondAnimalSelected")")
}
}
}
}
}
struct SummaryView_Previews: PreviewProvider {
static var previews: some View {
SummaryView()
}
}
enum Animal: String, CaseIterable {
case select
case bear
case cat
case dog
case lion
case tiger
}
struct ContentView: View {
#State private var firstAnimal = Animal.allCases[0]
#State private var secondAnimal = Animal.allCases[0]
var body: some View {
NavigationView {
Form {
Section(header: Text("Animals")
.foregroundColor(.black)
.font(.system(size: 15))
.fontWeight(.bold)) {
Picker(selection: $firstAnimal, label: Text("Select first animal")) {
ForEach(Animal.allCases, id: \.self) { element in
Text(element.rawValue.capitalized)
}
}
Picker(selection: $secondAnimal, label: Text("Select second animal")) {
ForEach(Animal.allCases.filter { $0 != firstAnimal || firstAnimal == .select }, id: \.self) { element2 in
Text(element2.rawValue.capitalized)
}
}
}.font(.system(size: 15))
}.navigationBarTitle("List", displayMode: .inline)
}
}
}

Answer 1

You can move your #State properties to an ObservableObject:
class ViewModel: ObservableObject {
#Published var firstAnimal = Animal.allCases[0]
#Published var secondAnimal = Animal.allCases[0]
}
and access them from an #EnvironmentObject:
struct ContentView: View {
#EnvironmentObject var viewModel: ViewModel
var body: some View {
...
Picker(selection: $viewModel.firstAnimal, label: Text("Select first animal")) {
ForEach(Animal.allCases, id: \.self) { element in
Text(element.rawValue.capitalized)
}
}
}
}
struct SummaryView: View {
#EnvironmentObject var viewModel: ViewModel
var body: some View {
NavigationView {
Form {
VStack(alignment: .leading, spacing: 6) {
Text("First Animal: \(viewModel.firstAnimal.rawValue)")
Text("Second Animal: \(viewModel.secondAnimal.rawValue)")
}
}
}
}
}
Remember to inject your ViewModel to your root view:
ContentView().environmentObject(ViewModel())