why data are passing back but SwiftUi not updating Text - swift

Question

I get to pass back data via closure, so new name is passed, but my UI is not updating. The new name of the user is printed when I go back to original view, but the text above the button is not getting that new value.
In my mind, updating startingUser should be enough to update the ContentView.
my ContentView:
#State private var startingUser: UserData?
var body: some View {
VStack {
Text(startingUser?.name ?? "no name")
Text("Create start user")
.onTapGesture {
startingUser = UserData(name: "Start User")
}
}
.sheet(item: $startingUser) { userToSend in
DetailView(user: userToSend) { newOnePassedFromWhatDoneInEDitView in
startingUser = newOnePassedFromWhatDoneInEDitView
print("✅ \(startingUser?.name)")
}
}
}
my EditView:
struct DetailView: View {
#Environment(\.dismiss) var dismiss
var user: UserData
var callBackClosure: (UserData) -> Void
#State private var name: String
var body: some View {
NavigationView {
Form {
TextField("your name", text: $name)
}
.navigationTitle("edit view")
.toolbar {
Button("dismiss") {
var newData = self.user
newData.name = name
newData.id = UUID()
callBackClosure(newData)
dismiss()
}
}
}
}
init(user: UserData, callBackClosure: #escaping (UserData) -> Void ) {
self.user = user
self.callBackClosure = callBackClosure
_name = State(initialValue: user.name)
}
}
struct DetailView_Previews: PreviewProvider {
static var previews: some View {
DetailView(user: UserData.example) { _ in}
}
}
my model
struct UserData: Identifiable, Codable, Equatable {
var id = UUID()
var name: String
static let example = UserData(name: "Luke")
static func == (lhs: UserData, rhs: UserData) -> Bool {
lhs.id == rhs.id
}
}
update
using these changes solves the matter, but my question remains valid, cannot understand the right reason why old code not working, on other projects, where sheet and text depends on the same #state var it is working.
adding
#State private var show = false
adding
.onTapGesture {
startingUser = UserData(name: "Start User")
show = true
}
changing
.sheet(isPresented: $show) {
DetailView(user: startingUser ?? UserData.example) { newOnePassedFromWhatDoneInEDitView in
startingUser = newOnePassedFromWhatDoneInEDitView
print("✅ \(startingUser!.name)")
}
}

Answer 1

The reason Text is not showing you the updated user name that you are passing in the closure is, your startingUser property will be set to nil when you dismiss the sheet because you have bind that property with sheet. Now after calling callBackClosure(newData) you are calling dismiss() to dismiss the sheet. To overcome this issue you can try something like this.
struct ContentView: View {
#State private var startingUser: UserData?
#State private var updatedUser: UserData?
var body: some View {
VStack {
Text(updatedUser?.name ?? "no name")
Text("Create start user")
.onTapGesture {
startingUser = UserData(name: "Start User")
}
}
.sheet(item: $startingUser) { userToSend in
DetailView(user: userToSend) { newUser in
updatedUser = newUser
print("✅ \(updatedUser?.name ?? "no name")")
}
}
}
}
I would suggest you to read the Apple documentation of sheet(item:onDismiss:content:) and check the example from the Discussion section to get more understanding.