Using Picker with Core Data - swift

Question

I have seen a number of responses about similar issues on here, but the picker for $category in the code below doesn't seem to work. When I select the picker, I see the list of categoryNames, but when I choose one, it doesn't get populated into $category.
I have 2 CoreData entities:
Expenses
expenseAccount:String
expenseCategory:String
expenseCost:Double
expenseDate:Date
expenseId:UUID
expenseIsMonthly:Bool
expenseName:String
Categories
categoryName:String
import SwiftUI
import CoreData
struct ExpenseDetail: View {
#FetchRequest(
entity: Categories.entity(),
sortDescriptors: [
NSSortDescriptor(keyPath: \Categories.categoryName, ascending: true)
]
)
private var result: FetchedResults<Categories>
var logToEdit: Expenses?
#Environment(\.managedObjectContext) var context
#State var name: String = ""
#State var amount: String = ""
#State var category: String = ""
#State var date: Date = Date()
#State var account: String = ""
#State var isMonthly: Bool = false
var currencyFormatter: NumberFormatter = {
let f = NumberFormatter()
f.numberStyle = .currency
return f
}()
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView {
Form{
TextField("Expense Name", text: $name)
Section{
HStack{
TextField("$\(amount)", text: $amount)
.keyboardType(.decimalPad)
.textFieldStyle(PlainTextFieldStyle())
.disableAutocorrection(true).multilineTextAlignment(.leading)
}
DatePicker(selection: $date, displayedComponents: .date) {
Text("Date")
}.onAppear{self.hideKeyboard()}
Picker(selection: $category, label: Text("Category")) {
ForEach(result) { (log: Categories) in
Text(log.categoryName ?? "No Category").tag(log.categoryName)
}
}
Picker(selection: $account, label: Text("Account")) {
ForEach(result) { (log: Categories) in
self.Print("\(log.categoryName ?? "")")
Button(action: {
// TODO: Implement Edit
}) {
Text(log.categoryName!.capitalized).tag(self.category)
}
}
}
Toggle(isOn: $isMonthly) {
Text("Monthly Expense")
}.toggleStyle(CheckboxToggleStyle())
}
Section{
Button(action: {
onSaveTapped()
}) {
HStack {
Spacer()
Text("Save")
Spacer()
}
}
}
Section{
Button(action: {
self.presentationMode.wrappedValue.dismiss()
}) {
HStack {
Spacer()
Text("Cancel").foregroundColor(.red)
Spacer()
}
}
}
}.navigationBarTitle("Add Expense")
}
}
private func onSaveTapped() {
let expenseLog: Expenses
if let logToEdit = self.logToEdit {
expenseLog = logToEdit
} else {
expenseLog = Expenses(context: self.context)
expenseLog.expenseId = UUID()
}
expenseLog.expenseName = self.name
expenseLog.expenseCategory = self.category
print("\(expenseLog.expenseName ?? "") category Picker: \(self.category)")
print("\(expenseLog.expenseName ?? "") ExpenseCategory: \(expenseLog.expenseCategory!)")
expenseLog.expenseCost = Double(self.amount) ?? 0
print("\(expenseLog.expenseName ?? "") Amount: \(self.amount)")
print("\(expenseLog.expenseName ?? "")ExpenseCost: \(expenseLog.expenseCost)")
expenseLog.expenseDate = self.date
expenseLog.expenseAccount = self.account
expenseLog.expenseIsMonthly = self.isMonthly
do {
try context.save()
} catch let error as NSError {
print(error.localizedDescription)
}
self.presentationMode.wrappedValue.dismiss()
}
}

Answer 1

The type of the selection value is String while Category.categoryName is String?. Notice the added ?, this means it is an Optional.
It is the default type for CoreData, but you can remove the Optional value inside the model:
I would ask myself does a Category without a name make sense before doing this change. If it does, you will probably have to use another identifier for the selection.