SwiftUI Picker with Cloud Firestore - xcode

Question

I was wondering whether I was able to get some help on this one, I've been trying a while to get things working and functioning properly and have been able to pass the Firestore data into the picker view, but I'm unable to select the data to view in the 'selected' area. I have added my code and my Firestore setup.
Thanks in advance.
import SwiftUI
import Firebase
struct SchoolDetailsView: View {
#ObservedObject var schoolData = getSchoolData()
#State var selectedSchool: String!
var body: some View {
VStack {
Form {
Section {
Picker(selection: $selectedSchool, label: Text("School Name")) {
ForEach(self.schoolData.datas) {i in
Text(self.schoolData.datas.count != 0 ? i.name : "No Schools Available").tag(i.name)
}
}
Text("Selected School: \(selectedSchool)")
}
}.navigationBarTitle("Select your school")
}
}
}
struct SchoolPicker_Previews: PreviewProvider {
static var previews: some View {
SchoolDetailsView()
}
}
class getSchoolData : ObservableObject{
#Published var datas = [schoolName]()
init() {
let db = Firestore.firestore()
db.collection("School Name").addSnapshotListener { (snap, err) in
if err != nil{
print((err?.localizedDescription)!)
return
}
for i in snap!.documentChanges{
let id = i.document.documentID
let name = i.document.get("Name") as! String
self.datas.append(schoolName(id: id, name: name))
}
}
}
}
struct schoolName : Identifiable {
var id : String
var name : String
}
Firestore Setup Image

Answer 1

To solve the issue with the code above the you can cast the tag to be the same type as the selectedSchool variable. This should then allow it to be selectable and is also safer as it uses optionals and allows the picker to be initially set to nil.
Example Code:
struct SchoolDetailsView: View {
#ObservedObject var schoolData = getSchoolData()
#State var selectedSchool: String?
var body: some View {
NavigationView {
VStack {
Form {
Section {
Picker(selection: $selectedSchool, label: Text("School Name")) {
ForEach(self.schoolData.datas.sorted(by: { $0.name < $1.name } )) {i in
Text(self.schoolData.datas.count != 0 ? i.name : "No Schools Available").tag(i.name as String?)
}
}
Text("Selected School: \(selectedSchool ?? "No School Selected")")
}
}.navigationBarTitle("Select your school")
}
}
}
}
As an alternative to the example above, you could also change the selectedSchool variable to be a schoolName type and cast the tag to be schoolName and this will also work. The only caveat with this approach is that the schoolName type must conform to the Hashable protocol.
Example Alternative Code:
struct schoolName: Identifiable, Hashable {
var id: String
var name: String
}
struct SchoolDetailsView: View {
#ObservedObject var schoolData = getSchoolData()
#State var selectedSchool: schoolName?
var body: some View {
NavigationView {
VStack {
Form {
Section {
Picker(selection: $selectedSchool, label: Text("School Name")) {
ForEach(self.schoolData.datas.sorted(by: { $0.name < $1.name } )) {i in
Text(self.schoolData.datas.count != 0 ? i.name : "No Schools Available").tag(i as schoolName?)
}
}
Text("Selected School: \(selectedSchool?.name ?? "No School Selected")")
}
}.navigationBarTitle("Select your school")
}
}
}
}
Either of these code examples should result in a working picker as follows:
Finally, as a side note for anyone when working with SwiftUI's default list view picker style, it must be enclosed within a NavigationView somewhere within the view hierarchy. This tripped me up when I first started using them :)