StateObject does not change on Appear but changes value on Button Tap - swift

Question

On Clicking the Button present in BillContributorView.swift, the view updates but not on Appear. I have tried swapping StateObject with ObservedObject but not only does it not help but also, I read that we should instantiate our ObservableObject with StateObject.
BillContributorView.swift
#StateObject var billManager = BillManager()
var body: some View {
VStack {
HStack {
Text("Get: \(String(format: "%.2f", billManager.toGetAmount))")
.font(.footnote)
Button {
billManager.updateToGet(contributorID: memberID)
} label: { Text("To Get") }
}
.onAppear(perform: {
billManager.updateRoomID(name: roomID)
billManager.updateToGet(contributorID: memberID )
})
}
BillManager
class BillManager: ObservableObject {
#Published var roomID: String
#Published var toGetbills = [Bill]()
#Published var toGetAmount: Double = 0
init(name: String? = nil) {
if let name = name {
roomID = name
} else {
roomID = ""
}
}
func updateRoomID(name: String) {
roomID = name
}
func updateToGet(contributorID: String) {
let collectionName = "\(roomID)_BILLS"
toGetAmount = 0
db.collection(collectionName)
.whereField("payer", isEqualTo: Auth.auth().currentUser?.uid ?? "")
.whereField("contributor", isEqualTo: contributorID)
.addSnapshotListener { snapshot, error in
DispatchQueue.main.async {
guard let doc = snapshot?.documents else {
print("No Doc Found")
return
}
self.toGetbills = doc.compactMap { queryDocumentSnapshot -> Bill? in
let result = Result { try queryDocumentSnapshot.data(as: Bill.self) }
switch result {
case .success(let bill):
return bill
}
}
}
}
toGetAmount = 0
for bill in toGetbills {
toGetAmount += bill.itemPrice
}
}

Answer 1

Fixed the issue by updating the value inside the closure.
db.collection(collectionName)
.whereField("payer", isEqualTo: Auth.auth().currentUser?.uid ?? "")
.whereField("contributor", isEqualTo: contributorID)
.addSnapshotListener { snapshot, error in
self.toGetAmount = 0
guard let doc = snapshot?.documents else {
print("No Doc Found")
return
}
DispatchQueue.main.async {
self.toGetbills = doc.compactMap { queryDocumentSnapshot -> Bill? in
let result = Result { try queryDocumentSnapshot.data(as: Bill.self) }
switch result {
case .success(let bill):
self.toGetAmount += bill.itemPrice
return bill
case .failure( _):
print("Failure To Get Bill Request")
return nil
}
}
}
}