SwiftUI - Picker value not changing when accessing data from UserDefaults - swiftui

Question

I am making an app where I am showing different views based of user's selection by a picker. The binding value of the picker is initially set by UserDefaults in a viewModel. The problem is when I choose a picker value in my app, The picker automatically go back to initial state, as if someone forcing the picker not the change the values.
Settings ViewModel :
import Foundation
class SettingsViewModel:ObservableObject{
#Published var showSettings = false
//Here is the problem
#Published var choosenUserType = UserDefaults.standard.string(forKey: "userType"){
didSet{
UserDefaults.standard.set(self.choosenUserType, forKey: "userType")
}
}
static var userTypes = ["Client", "Worker"]
}
Home View:
import SwiftUI
struct HomeView: View {
#StateObject var settingsVM = SettingsViewModel()
var body: some View {
VStack{
switch settingsVM.choosenUserType{
case "Client":
Text("This is client")
case "Worker":
Text("This is worker")
default:
Text("This is default")
}
}.navigationTitle("Tanvirgeek Co")
.navigationBarItems(trailing: Button(action: {
settingsVM.showSettings.toggle()
}, label: {
Text("Settings")
}))
.sheet(isPresented: $settingsVM.showSettings, content: {
SettingsView(dissmiss: $settingsVM.showSettings)
.environmentObject(settingsVM)
})
}
}
Settings View:
import SwiftUI
struct SettingsView: View {
#EnvironmentObject var settingVM:SettingsViewModel
#Binding var dissmiss:Bool
var body: some View {
VStack{
Picker(selection: $settingVM.choosenUserType, label: Text("Choose User Type"), content: {
ForEach(SettingsViewModel.userTypes, id: \.self) { userType in
Text("\(userType)")
}
})
Button(action: {
dissmiss.toggle()
}, label: {
Text("Dismiss")
})
}
}
}
What I am doing wrong? How to change the picker's binding variable value through the picked value here?

Answer 1

Your choosenUserType ends up with an inferred type of String? because that's what UserDefaults.string(forKey:) returns.
The Picker's selection type needs to match exactly with the tag type. The tags (which are inferred in this case as well) are of type String.
I've solved this by giving a default value to choosenUserType so that it can be a String (not String?):
class SettingsViewModel:ObservableObject{
#Published var showSettings = false
#Published var choosenUserType : String = UserDefaults.standard.string(forKey: "userType") ?? SettingsViewModel.userTypes[0] {
didSet{
UserDefaults.standard.set(self.choosenUserType, forKey: "userType")
}
}
static var userTypes = ["Client", "Worker"]
}
Also, in your SettingsView, you don't have to interpolate the userType in the Text -- you can just provide it directly:
struct SettingsView: View {
#EnvironmentObject var settingVM:SettingsViewModel
#Binding var dissmiss:Bool
var body: some View {
VStack{
Picker(selection: $settingVM.choosenUserType, label: Text("Choose User Type")) {
ForEach(SettingsViewModel.userTypes, id: \.self) { userType in
Text(userType)
}
}
Button(action: {
dissmiss.toggle()
}, label: {
Text("Dismiss")
})
}
}
}