How we get the data and show like viewdidload using swiftUI - ios

Question

i'm trying to work with swiftUI but i'm having an issue. i want to fetch the data from firebase and show that data to the list. i used mutating function to modify the variable. now when i called that function than it give me error. how i can solve this please help me. below are the code i'm using.
struct UserListView : View {
var body: some View{
VStack{
List{
VStack(alignment:.leading){
HStack{
Text("Favroute").frame(alignment: .leading).padding(.leading, 20)
Spacer()
Text("All").frame(alignment: .trailing)
}
ScrollView(.horizontal, content: {
HStack(spacing: 10) {
ForEach(0..<10) { index in
StatusView(statusImage: "nature")
}
}
.padding(.leading, 10)
})
.frame(height: 190)
}
ForEach(0..<10){_ in
HStack{
Group{
NavigationLink(destination: ChatView()){
UserImageView(imageName: "profileDummy").padding(.leading, 5)
Text("User Name").padding(.leading,10)
}
}
}.frame( height: 40)
}.environment(\.defaultMinListRowHeight, 40)
}
}
.navigationBarTitle("UserList",displayMode: .inline)
.onAppear {
self.userList()
}
}
var userDataList = [UserModel]()
mutating func userList() {
databaseReference.child(DatabaseNode.Users.root.rawValue).observe(.value) { (snapShot) in
if snapShot.exists(){
if let friendsDictionary = snapShot.value{
for each in friendsDictionary as! [String : AnyObject]{
print(each)
if let user = each.value as? [String : Any]{
let data = UserModel(userId: JSON(user["userId"] ?? "").stringValue, name: JSON(user["name"] ?? "").stringValue)
print(data)
self.userDataList.append(data)
}
}
}
}
}
}
}
below are the error message i'm getting:
Cannot use mutating member on immutable value: 'self' is immutable

Answer 1

You should declare your userDataList property like so #State var userDataList = [UserModel](). This way this property will be stored by SwiftUI outside of your struct and can be mutated.