Swift UI understanding on observable classes - swift

Question

Ok so my content view is this
import SwiftUI
struct ContentView: View {
#ObservedObject private var user = User()
var body: some View {
VStack {
ShowName()
TextField("First name", text: $user.firstName)
TextField("Last name", text: $user.lastName)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I migrated my class to swift file
import Foundation
class User: ObservableObject {
#Published var firstName = "Bilbo"
#Published var lastName = "Baggins"
}
Then I moved the single view into an external view file
import SwiftUI
struct ShowName: View {
#ObservedObject private var user = User()
var body: some View {
Text("Your name is \(user.firstName) \(user.lastName)")
.padding()
}
}
struct ShowName_Previews: PreviewProvider {
static var previews: some View {
Testing()
}
}
I have Observed the same class but it does not update, when the class and view were in the
Is there something I need to do special in the ShowName() view to make it observe the class, or am I missing the point entirely.
When the main view bound to the class updates the class, the ShowName view is not updated, I know this is me not understanding it but its so hard to ask Google with something like this, so please be kind, im 47 and learning a new language ;)
Sorry ive only been doing swift a few days migrating from Angular/c++/PHP

Answer 1

In ContentView Change
#StateObject private var user = User()
And
ShowName(user: user)
Then in ShowName remove the initializer
#ObservedObject var user = User
Every time you initialize User() you get a different instance one does not know what the other is doing.
The change to state object is because it is unsafe to use #ObservedObject like that.
https://developer.apple.com/documentation/swiftui/managing-model-data-in-your-app

Answer 2

That is because the instance of User is unique in both of those views. To correct it, you would want to pass in the user to the ShowName view instead of create a new one in the view itself. It would look something like this:
struct ShowName: View {
#ObservedObject private var use: User
init(_ user: User) {
self.user = user
}
var body: some View {
Text("Your name is \(user.firstName) \(user.lastName)")
.padding()
}
}
Then in content view you would initialize it like:
ShowName(user)
The important thing to realize is that every time you write User() a new user instance is created. Where this change would pass the same user from content view to the show name view.
I’m writing this from my phone so something may be a little off.