SwiftUI List Rows Not Refreshed After Updating Binding In Other Screen - ios

Question

I have a simple watchOS SwiftUI Application. The application has three screens. The first screen consists of a List of items. When you press that item, it will redirect to another screen & when you tap a button there it will open up a .sheet View which allows you to edit the item in the list.
The first view looks like this:
class Object: NSObject {
var title: String
init(title: String) {
self.title = title
}
}
struct Row: View {
#Binding var object: Object
var body: some View {
Text(self.object.title)
}
}
struct ContentView: View {
#State private var objects = [Object]()
var body: some View {
NavigationView {
List {
ForEach(objects.indices, id: \.self) { idx in
NavigationLink(destination: SecondView(object: self.$objects[idx])) {
Row(object: self.$objects[idx])
}
}
}
}
.onAppear {
self.objects = [
Object(title: "Test 1"),
Object(title: "Test 2")
]
}
}
}
These are the second & third views:
struct SecondView: View {
#Binding var object: Object
#State private var showPicker: Bool = false
var body: some View {
VStack {
Text(object.title)
Button(action: {
self.showPicker.toggle()
}) {
Text("Press Here")
}
}
.sheet(isPresented: $showPicker) {
ThirdView(object: self.$object)
}
}
}
struct ThirdView: View {
#Binding var object: Object
var body: some View {
VStack {
Text(object.title)
Button(action: {
self.update()
}, label: {
Text("Tap here")
})
}
}
func update() {
let newObj = self.object
newObj.title = "Hello, World!"
self.object = newObj
}
}
I'd expect, whenever I tap the button in the third view, the Binding (and thus the State) get's updated with "Hello, World". However, that is not the case, although not immediately.
What I currently see happening is that when I tap the button in the third view, the Text in that view does not get updated. When I dismiss the third view and go back to the second view, I do see "Hello, World". But when I go back to the list, the row still has the old value.
One other thing I noticed is that, when I fill the array of objects directly, like so:
#State private var objects = [Object(title: "Test 1"), Object(title: "Test 2")]
and remove the filling of the array in .onAppear, this work totally how I'd expect it to (everything updates immediately to "Hello, World".
Does anyone one know what I'm doing wrong here or did I might hit a bug?
Thanks!

Answer 1

Complex objects need to be classes conforming to #ObservableObject.
Observed ivars need to be published.
class Object: ObservableObject {
#Published var title: String
[...]
}
Observing views would use them as #ObservedObject
struct Row: View {
#ObservedObject var object: Object
[...]
}
You might have to create an object wrapper for your lists
class ObjectList: ObservableObject {
#Published var objects: [Object]
[...]
}