Swiftui append to a struct array doesn't work - arrays

Question

Im learning swiftui at this moment. But now i have come across a problem.
Im trying to append data to an array that is an struct.
struct outfit:Identifiable {
var id = UUID()
var user: String
var amount: Double
var rating: Double
}
and the other file
import SwiftUI
import Firebase
import FirebaseStorage
import FirebaseFirestore
struct rate: View {
private var db = Firestore.firestore()
#State var user = Auth.auth().currentUser
#State private var outfitcards = [outfit]()
#State private var cards = [1, 2, 3]
#State private var offset = [CGSize.zero, CGSize.zero]
init () {
loadcards()
}
var body: some View {
GeometryReader { frame in
ZStack{
VStack {
Text("outfit")
.font(.largeTitle)
.padding()
ZStack {
Text("No cards to show")
.frame(width: frame.size.width * 0.6, height: frame.size.width * 1.6)
HStack {
Image(systemName: "record.circle.fill")
.foregroundColor(.red)
Spacer()
Image(systemName: "record.circle.fill")
.foregroundColor(.green)
}
ForEach(outfitcards) { index in
Text(index.user)
}
}
}
}
}
}
func loadcards () {
db.collection("rating").whereField("user", isNotEqualTo: user?.uid ?? "Error")
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err.localizedDescription)")
} else {
for document in querySnapshot!.documents {
let cuser = document.get("user") as! String
let camount = document.get("amount") as! Double
let crating = document.get("rating") as! Double
print("user=\(cuser) amount=\(camount) crating=\(crating)")
outfitcards.append(outfit(user: cuser, amount: camount, rating: crating))
}
print(outfitcards)
}
}
}
}
It does print the username, the amount and the rating but then when i print the array itself it is giving me a []. So it doens't append. Also the for each loop is empty so that also means that the array is empty
and nothing is appended
Does anyone know what I do wrong?

Answer 1

Loading data in a View like that is a dangerous practice and it'll get reset/reloaded any time that view is re-rendered (or even re-inited in this case).
Instead, move your code that loads the data to an ObservableObject:
struct Outfit:Identifiable {
var id = UUID()
var user: String
var amount: Double
var rating: Double
}
class Loader : ObservableObject {
private var db = Firestore.firestore()
private var user = Auth.auth().currentUser
#Published var outfitcards = [Outfit]()
func loadcards () {
db.collection("rating").whereField("user", isNotEqualTo: user?.uid ?? "Error")
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err.localizedDescription)")
} else {
for document in querySnapshot!.documents {
let cuser = document.get("user") as! String
let camount = document.get("amount") as! Double
let crating = document.get("rating") as! Double
print("user=\(cuser) amount=\(camount) crating=\(crating)")
self.outfitcards.append(Outfit(user: cuser, amount: camount, rating: crating))
}
print(self.outfitcards)
}
}
}
}
struct Rate: View {
#StateObject var loader = Loader()
#State private var cards = [1, 2, 3]
#State private var offset = [CGSize.zero, CGSize.zero]
var body: some View {
GeometryReader { frame in
ZStack{
VStack {
Text("outfit")
.font(.largeTitle)
.padding()
ZStack {
Text("No cards to show")
.frame(width: frame.size.width * 0.6, height: frame.size.width * 1.6)
HStack {
Image(systemName: "record.circle.fill")
.foregroundColor(.red)
Spacer()
Image(systemName: "record.circle.fill")
.foregroundColor(.green)
}
ForEach(loader.outfitcards) { index in
Text(index.user)
}
}
}
}
}.onAppear {
loader.loadcards()
}
}
}
Now, the loader is responsible for making the database call. It updates a #Published property, which the View observes.
Note that I changed the capitalization of a few things (Rate, Outfit). In Swift, the common practice is to capitalize types (classes/structs/enums) and start variable names with lowercase letters.
Also probably worth noting that the way that you're casting the data from firebase (with as!) is dangerous and can crash your program if the data isn't in the format you expect. Better to use optional binding (let user = document.get("user") as? String)

Answer 2

Your issue is there you are updating #State value in initializing View, which you are doing in Wrong way, do like this onAppear:
struct rate: View {
private var db = Firestore.firestore()
#State var user = Auth.auth().currentUser
#State private var outfitcards = [outfit]()
#State private var cards = [1, 2, 3]
#State private var offset = [CGSize.zero, CGSize.zero]
var body: some View {
GeometryReader { frame in
ZStack{
VStack {
Text("outfit")
.font(.largeTitle)
.padding()
ZStack {
Text("No cards to show")
.frame(width: frame.size.width * 0.6, height: frame.size.width * 1.6)
HStack {
Image(systemName: "record.circle.fill")
.foregroundColor(.red)
Spacer()
Image(systemName: "record.circle.fill")
.foregroundColor(.green)
}
ForEach(outfitcards) { index in
Text(index.user)
}
}
}
}
}
.onAppear() { loadcards() } // <<: Here
}
func loadcards () {
db.collection("rating").whereField("user", isNotEqualTo: user?.uid ?? "Error")
.getDocuments() { (querySnapshot, err) in
if let err = err {
print("Error getting documents: \(err.localizedDescription)")
} else {
for document in querySnapshot!.documents {
let cuser = document.get("user") as! String
let camount = document.get("amount") as! Double
let crating = document.get("rating") as! Double
print("user=\(cuser) amount=\(camount) crating=\(crating)")
outfitcards.append(outfit(user: cuser, amount: camount, rating: crating))
}
print(outfitcards)
}
}
}
}