View not updating when accessing ObservableObject in Else block - ios

Question

My detail View does not update when I change its #Binding value.
struct ContentView: View {
class ViewModel: ObservableObject {
#Published var imageSize: ImageSize?
#Published var anotherValue: Int? = 5
var cancellable: AnyCancellable?
init() {
cancellable = $imageSize.sink(receiveValue: { imageSize in
print("🚨 \(imageSize?.rawValue ?? "Unknown")")
})
}
}
#ObservedObject private var viewModel = ViewModel()
var body: some View {
NavigationView {
List {
if viewModel.anotherValue == nil {
Text("Another value is nil")
} else {
NavigationLink(destination: SelectImageSizeView(selectedImageSize: $viewModel.imageSize)
.navigationBarTitle("ImageSize", displayMode: .inline)) {
Text("ImageSize: \(viewModel.imageSize?.rawValue ?? "Not Set")")
}
}
}
}
}
}
struct SelectImageSizeView: View {
#Binding var selectedImageSize: ImageSize?
var body: some View {
List{
ForEach(ImageSize.allCases, id: \.self) { imageSize in
HStack {
Button {
withAnimation {
self.selectedImageSize = imageSize
}
} label: {
HStack {
Text(imageSize.rawValue)
Image(systemName: imageSize == selectedImageSize ? "checkmark.circle.fill" : "circle")
}
.font(.title)
}
}
}
}
}
}
public enum ImageSize: String, Codable, CaseIterable {
case small = "Small"
case medium = "Medium"
case large = "Large"
}
It does work when I move the NavigationLink to out of the if block:
NavigationView {
List {
if viewModel.anotherValue == nil {
Text("Another value is nil")
}
NavigationLink(destination: SelectImageSizeView(selectedImageSize: $viewModel.imageSize)
.navigationBarTitle("ImageSize", displayMode: .inline)) {
Text("ImageSize: \(viewModel.imageSize?.rawValue ?? "Not Set")")
}
}
}
Am I missing something here?

Answer 1

Hm. I don't know why that's the case. But you could instead pass over your whole ViewModel?
You would have to put it outside your ContentView. I have made it fileprivate if you don't want to access it from other files.
Works for me.
fileprivate class ViewModel: ObservableObject {
#Published var imageSize: ImageSize?
#Published var anotherValue: Int? = 5
var cancellable: AnyCancellable?
init() {
cancellable = $imageSize.sink(receiveValue: { imageSize in
print("🚨 \(imageSize?.rawValue ?? "Unknown")")
})
}
}
struct ContentView: View {
#StateObject private var viewModel = ViewModel()
var body: some View {
NavigationView {
List {
if viewModel.anotherValue == nil {
Text("Another value is nil")
} else {
NavigationLink(destination: SelectImageSizeView(viewModel: viewModel)
.navigationBarTitle("ImageSize", displayMode: .inline)) {
Text("ImageSize: \(viewModel.imageSize?.rawValue ?? "Not Set")")
}
}
}
}
}
}
struct SelectImageSizeView: View {
#ObservedObject fileprivate var viewModel: ViewModel
var body: some View {
List{
ForEach(ImageSize.allCases, id: \.self) { imageSize in
HStack {
Button {
withAnimation {
viewModel.imageSize = imageSize
}
} label: {
HStack {
Text(imageSize.rawValue)
Image(systemName: imageSize == viewModel.imageSize ? "checkmark.circle.fill" : "circle")
}
.font(.title)
}
}
}
}
}
}
public enum ImageSize: String, Codable, CaseIterable {
case small = "Small"
case medium = "Medium"
case large = "Large"
}

Answer 2

It is very silly but there is bug in simulator. It is working with device.