Update view bugs when data in firebase changes - ios

Question

This is when I launch the app and it looks okThis is when I change some data from firebase, as you can see some data is not arranged in the right way and some rectangles are doubleI'm currently working on this project where I need do read data from Firebase and update my views from the changes. Every time my data changes on firebase my views bugs in strange ways.
This is my Student class
struct Student : Identifiable {
var id : String
var name : String
var surname : String
var isAbsent : Bool
var isBathroom : Bool
}
Here where I get my data from firebase and publish to get all other views the data
class getStudents: ObservableObject {
#Published var datas = [Student]()
init() {
let db = Firestore.firestore()
let classRef = db.collection("5SA")
classRef.order(by: "surname").addSnapshotListener {(snap,error) in
if error != nil{
print((error?.localizedDescription)!)
return
}
for i in snap!.documentChanges{
let id = i.document.documentID
let name = i.document.get("name")as! String
let surname = i.document.get("surname") as! String
let isAbsent = i.document.get("absent") as! Bool
let isBathroom = i.document.get("bathroom") as! Bool
self.datas.append(Student(id: id, name: name, surname: surname, isAbsent: isAbsent, isBathroom: isBathroom))
if i.type == .modified{
let isAbsent = i.document.get("absent") as! Bool
let isBathroom = i.document.get("bathroom") as! Bool
for j in 0..<self.datas.count{
if self.datas[j].id == id{
self.datas[j].isAbsent = isAbsent
self.datas[j].isBathroom = isBathroom
}
}
}
}
}
}
}
This are my views. Apart from the landscape on the iPad simulator the bugs every time.
What I'm trying to achieve is creating like a class app. Where there are students absent, in the toilet or present. I want to to show every student with a rectangle with his name on it and to change color of the rectangles every time the bools on my fire base changes(isAbsent,isBathroom). But when I try to change value on firebase the rectangles multiplies and do strange thinks.
struct ContentView: View {
#ObservedObject var students = getStudents()
var body: some View {
NavigationView{
VStack{
ScrollView{
Text("Menu")
Menu().background(Color.white)
Text("Future verifiche")
HStack{
ScrollView(.horizontal, showsIndicators: false){
RoundedRectangle(cornerRadius: 20).frame(width:300,height: 300).foregroundColor(.white).overlay(Text("V. Matematica"))
}
}
Text("Oggi")
HStack{
Spacer()
Text("Assenti ")
Spacer()
Text("In bagno")
Spacer()
Text("Presenti")
Spacer()
}
HStack{
Spacer()
ScrollView{
ForEach(students.datas,id: \.id){student in
VStack(spacing: 15){
if student.isAbsent{
RoundedRectangle(cornerRadius: 20).frame(width:200,height: 100).foregroundColor(self.getColor(isAbsent: student.isAbsent, isBathroom: student.isBathroom)).overlay(Text(student.name))
}
}
}
}
Spacer()
ScrollView{
ForEach(students.datas,id: \.id){student in
VStack(spacing: 15){
if student.isBathroom{
RoundedRectangle(cornerRadius: 20).frame(width:200,height: 100).foregroundColor(self.getColor(isAbsent: student.isAbsent, isBathroom: student.isBathroom)).overlay(Text(student.name))
}
}
}
}
Spacer()
ScrollView{
ForEach(students.datas,id: \.id){student in
VStack(spacing: 15){
if !student.isAbsent && !student.isBathroom{
RoundedRectangle(cornerRadius: 20).frame(width:200,height: 100).foregroundColor(self.getColor(isAbsent: student.isAbsent, isBathroom: student.isBathroom)).overlay(Text(student.name))
}
}
}
}
Spacer()
}
}
}.navigationBarTitle("Classe 5SA",displayMode: .inline)
}.navigationViewStyle(StackNavigationViewStyle())
}
func getColor(isAbsent: Bool, isBathroom : Bool) -> Color {
if isAbsent{
return Color.red
}
if isBathroom{
return Color.blue
}
return Color.green
}
}
struct Menu : View {
var body : some View{
HStack{
NavigationLink(destination: Studenti()){
RoundedRectangle(cornerRadius: 30).frame(width: 150,height: 150).foregroundColor(.red).opacity(0.5).overlay(Text("Studenti").foregroundColor(.black))
}
NavigationLink(destination: Text("Overview")){
RoundedRectangle(cornerRadius: 30).frame(width: 150,height: 150).foregroundColor(.green).opacity(0.5).overlay(Text("Overview").foregroundColor(.black))
}
NavigationLink(destination: Text("Orario")){
RoundedRectangle(cornerRadius: 30).frame(width: 150,height: 150).foregroundColor(.blue).opacity(0.5).overlay(Text("Orario").foregroundColor(.black))
}
NavigationLink(destination: Text("Calendario")){
RoundedRectangle(cornerRadius: 30).frame(width: 150,height: 150).foregroundColor(.orange).opacity(0.5).overlay(Text("Calendario").foregroundColor(.black))
}
}
}
}
struct Studenti : View {
#ObservedObject var students = getStudents()
var body : some View {
ForEach(students.datas,id: \.id){student in
VStack{
Rectangle().frame(width:300,height: 150).foregroundColor(self.getColor(isAbsent: student.isAbsent, isBathroom: student.isBathroom)).overlay(Text(student.name))
}
}
}
func getColor(isAbsent: Bool, isBathroom : Bool) -> Color {
if isAbsent{
return Color.red
}
if isBathroom{
return Color.blue
}
return Color.green
}
}