Entries from text field are not adding into list - swift

Question

import SwiftUI
import Firebase
import FirebaseFirestore
struct ContentView: View {
var body: some View {
customView()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
struct customView : View{
#State var msg = ""
#ObservedObject var datas = observer()
var body : some View{
VStack{
List{
ForEach(datas.data){i in
Text(i.msg)
}
.onDelete { (index) in
let id = self.datas.data[index.first!].id
let db = Firestore.firestore().collection("msgs")
db.document(id).delete{(err) in
if err != nil{
print((err!.localizedDescription))
return
}
print("deleted Successfully !!!")
self.datas.data.remove(atOffsets: index)
}
}
}
HStack{
TextField("msg", text: $msg).textFieldStyle(RoundedBorderTextFieldStyle())
Button(action: {
print(self.msg)
self.addData(msg1: self.msg)
}) {
Text("Add")
}.padding()
}.padding()
}
}
func addData(msg1:String){ 'Here is the code for additon'
let db = Firestore.firestore()
let msg = db.collection("msgs").document()
msg.setData(["id":msg.documentID,"msg": msg1]) { (err) in
if err != nil{
print((err?.localizedDescription)!)
return
}
print("Success")
self.msg = ""
}
}
}
class observer : ObservableObject{
#Published var data = [datatype]()
init() {
let db = Firestore.firestore().collection("msg")
db.addSnapshotListener{(snap, err) in
if err != nil{
print((err?.localizedDescription)!)
return
}
for i in snap!.documentChanges{
if i.type == .added{
let msgData = datatype(id: i.document.documentID, msg: i.document.get("msg")
as! String)
self.data.append(msgData)
}
}
}
}
}
struct datatype : Identifiable {
var id : String
var msg : String
}
Here is the code for the CRUD(creation, reading, update, delete) using the firebase cloud service. When i enter the text in the text field and then hit button, it adds to firebase database, but doesn't shows up in the interface in the list of the app. Can anybody tell me where i am going wrong?
In this i am trying to add data to firebase, delete it ,read it and modify/update it. But the data entered doesn't shows up in interface.

Answer 1

Try to update data container explicitly on main thread, like below
if i.type == .added{
let msgData = datatype(id: i.document.documentID, msg: i.document.get("msg")
as! String)
DispatchQueue.main.async {
self.data.append(msgData)
}
}
as alternate try assignment instead of modification (however this should not be the case)
DispatchQueue.main.async {
self.data = self.data + [msgData]
}