I have a view and I want to load the data from the database from the start of the view, because I want to edit the profile of my user.
So whenever I will start the my view, the data will be loaded.
This is my code but it gives me an exception on the TextField.
struct ProfileView: View {
#State var myUser = User()
var repo = myRepo()
var body: some View {
VStack{
Form{
Section(header: Text("edit the name")){
TextField("Nume produs", text: self.myUser.name) //IT DOES NOT WORK HERE
}
}
}.onAppear(){
getMyUser()
}
func getMyUser(){
Task{
do{
try await repo.getUserProfile().watch(block: {item in
self.myUser = item as! User
})
}catch{
print("error")
}
}
}
}
This just does not work when I put as a TextField
What is the best way to have the data of my object (myUser) right away on the start of the view?
Just init the String as empty and create the #Binding like so:
import SwiftUI
struct ProfileView: View {
#State var myUser = ""
var body: some View {
VStack{
Form{
Section(header: Text("edit the name")){
TextField("Nume produs", text: $myUser) //IT DOES NOT WORK HERE
}
}
}.onAppear(){
getMyUser()
}
}
func getMyUser() {
Task{
do{
try await Task.sleep(nanoseconds: 3_000_000_000)
myUser = "HELLO"
}catch{
print("error")
}
}
}
}
Related
The point of this app is to use core data to permanently add types of fruit to a list. I have two views: ContentView and SecondScreen. SecondScreen is a pop-up sheet. When I input a fruit and press 'save' in SecondScreen, I want to immediately update the list in ContentView to reflect the type of fruit that has just been added to core data as well as the other fruits which have previously been added to core data. My problem is that when I hit the 'save' button in SecondScreen, the new fruit is not immediately added to the list in ContentView. Instead, I have to restart the app to see the new fruit in the list.
Here is the class for my core data:
class CoreDataViewModel: ObservableObject {
let container: NSPersistentContainer
#Published var savedEntities: [FruitEntity] = []
init() {
container = NSPersistentContainer(name: "FruitsContainer")
container.loadPersistentStores { (description, error) in
if let error = error {
print("Error with coreData. \(error)")
}
}
fetchFruits()
}
func fetchFruits() {
let request = NSFetchRequest<FruitEntity>(entityName: "FruitEntity")
do {
savedEntities = try container.viewContext.fetch(request)
} catch let error {
print("Error fetching. \(error)")
}
}
func addFruit(text: String) {
let newFruit = FruitEntity(context: container.viewContext)
newFruit.name = text
saveData()
}
func saveData() {
do {
try container.viewContext.save()
fetchFruits()
} catch let error {
print("Error saving. \(error)")
}
}
}
Here is my ContentView struct:
struct ContentView: View {
//sheet variable
#State var showSheet: Bool = false
#StateObject var vm = CoreDataViewModel()
#State var refresh: Bool
var body: some View {
NavigationView {
VStack(spacing: 20) {
Button(action: {
showSheet.toggle()
}, label: {
Text("Add Fruit")
})
List {
ForEach(vm.savedEntities) { entity in
Text(entity.name ?? "NO NAME")
}
}
}
.navigationTitle("Fruits")
.sheet(isPresented: $showSheet, content: {
SecondScreen(refresh: $refresh)
})
}
}
}
Here is my SecondScreen struct:
struct SecondScreen: View {
#Binding var refresh: Bool
#Environment(\.presentationMode) var presentationMode
#StateObject var vm = CoreDataViewModel()
#State var textFieldText: String = ""
var body: some View {
TextField("Add fruit here...", text: $textFieldText)
.font(.headline)
.padding(.horizontal)
Button(action: {
guard !textFieldText.isEmpty else { return }
vm.addFruit(text: textFieldText)
textFieldText = ""
presentationMode.wrappedValue.dismiss()
refresh.toggle()
}, label: {
Text("Save")
})
}
}
To try and solve this issue, I've created a #State boolean variable called 'refresh' in ContentView and bound it with the 'refresh' variable in SecondScreen. This variable is toggled when the user hits the 'save' button on SecondScreen, and I was thinking that maybe this would change the #State variable in ContentView and trigger ContentView to reload, but it doesn't work.
In your second screen , change
#StateObject var vm = CoreDataViewModel()
to
#ObservedObject var vm: CoreDataViewModel
then provide for the instances that compiler will ask for
hope it helps
You need to use #FetchRequest instead of #StateObject and NSFetchRequest. #FetchRequest will call body to update the Views when the fetch result changes.
I have a list of fruits. the struct FruitRowView provides the layout for the view of each row. In this FruitRowView, there's a TextField which I want to display the name of each fruit. I am having trouble doing this. The reason why I want to use a TextField to display the name of each fruit rather than a Text is so that users can easily edit the name of the fruit right from that TextField. In this case, fruits are the Core Data entity and the fruit name is an attribute of this entity.
Here is my core data class:
class CoreDataViewModel: ObservableObject {
let container: NSPersistentContainer
#Published var savedEntities: [FruitEntity] = []
init() {
container = NSPersistentContainer(name: "FruitsContainer")
container.loadPersistentStores { (description, error) in
if let error = error {
print("Error with coreData. \(error)")
}
}
fetchFruits()
}
func fetchFruits() {
let request = NSFetchRequest<FruitEntity>(entityName: "FruitEntity")
do {
savedEntities = try container.viewContext.fetch(request)
} catch let error {
print("Error fetching. \(error)")
}
}
func addFruit(text: String) {
let newFruit = FruitEntity(context: container.viewContext)
newFruit.name = text
saveData()
}
func saveData() {
do {
try container.viewContext.save()
fetchFruits()
} catch let error {
print("Error saving. \(error)")
}
}
}
Here is my contentView:
struct ContentView: View {
//sheet variable
#State var showSheet: Bool = false
#StateObject var vm = CoreDataViewModel()
#State var refresh: Bool
var body: some View {
NavigationView {
VStack(spacing: 20) {
Button(action: {
showSheet.toggle()
}, label: {
Text("Add Fruit")
})
List {
ForEach(vm.savedEntities) { fruit in
FruitRowView(vm: vm, fruit: fruit)
}
}
}
.navigationTitle("Fruits")
.sheet(isPresented: $showSheet, content: {
SecondScreen(refresh: $refresh, vm: vm)
})
}
}
}
Here is my popup screen (used to create a new fruit)
struct SecondScreen: View {
#Binding var refresh: Bool
#Environment(\.presentationMode) var presentationMode
#ObservedObject var vm: CoreDataViewModel
#State var textFieldText: String = ""
var body: some View {
TextField("Add fruit here...", text: $textFieldText)
.font(.headline)
.padding(.horizontal)
Button(action: {
guard !textFieldText.isEmpty else { return }
vm.addFruit(text: textFieldText)
textFieldText = ""
presentationMode.wrappedValue.dismiss()
refresh.toggle()
}, label: {
Text("Save")
})
}
}
Here is my FruitRowView:
struct FruitRowView: View {
//instance of core data model
#ObservedObject var vm: CoreDataViewModel
var fruit: FruitEntity
#State var fruitName = fruit.name
var body: some View {
TextField("Enter fruit name", text: $fruitName)
}
}
So the error that I'm getting is: 'Cannot use instance member 'fruit' within property initializer; property initializers run before 'self' is available'. This error occurs in the FruitRowView when I try to assign fruitName to fruit.name. I assume that there's an easy workaround for this but I haven't been able to figure it out.
Since the fruitEntities in the view model is a published property, you don't need a state variable in the row. You need the binding for the row view, and you should pass it in the content view.
You don't need to pass the view model to the row view as well.
struct FruitRowView: View {
// No need to pass view model to child, only pass the data
// #ObservedObject var vm: CoreDataViewModel
#Binding var fruitName: String
// You don't need this.
// #State var fruitName = fruit.name
var body: some View {
TextField("Enter fruit name", text: $fruitName)
}
}
struct ContentView: View {
...
List {
ForEach(vm.savedEntities) { fruit in
FruitRowView(fruitName: $fruit.name)
}
}
...
}
I get to pass back data via closure, so new name is passed, but my UI is not updating. The new name of the user is printed when I go back to original view, but the text above the button is not getting that new value.
In my mind, updating startingUser should be enough to update the ContentView.
my ContentView:
#State private var startingUser: UserData?
var body: some View {
VStack {
Text(startingUser?.name ?? "no name")
Text("Create start user")
.onTapGesture {
startingUser = UserData(name: "Start User")
}
}
.sheet(item: $startingUser) { userToSend in
DetailView(user: userToSend) { newOnePassedFromWhatDoneInEDitView in
startingUser = newOnePassedFromWhatDoneInEDitView
print("✅ \(startingUser?.name)")
}
}
}
my EditView:
struct DetailView: View {
#Environment(\.dismiss) var dismiss
var user: UserData
var callBackClosure: (UserData) -> Void
#State private var name: String
var body: some View {
NavigationView {
Form {
TextField("your name", text: $name)
}
.navigationTitle("edit view")
.toolbar {
Button("dismiss") {
var newData = self.user
newData.name = name
newData.id = UUID()
callBackClosure(newData)
dismiss()
}
}
}
}
init(user: UserData, callBackClosure: #escaping (UserData) -> Void ) {
self.user = user
self.callBackClosure = callBackClosure
_name = State(initialValue: user.name)
}
}
struct DetailView_Previews: PreviewProvider {
static var previews: some View {
DetailView(user: UserData.example) { _ in}
}
}
my model
struct UserData: Identifiable, Codable, Equatable {
var id = UUID()
var name: String
static let example = UserData(name: "Luke")
static func == (lhs: UserData, rhs: UserData) -> Bool {
lhs.id == rhs.id
}
}
update
using these changes solves the matter, but my question remains valid, cannot understand the right reason why old code not working, on other projects, where sheet and text depends on the same #state var it is working.
adding
#State private var show = false
adding
.onTapGesture {
startingUser = UserData(name: "Start User")
show = true
}
changing
.sheet(isPresented: $show) {
DetailView(user: startingUser ?? UserData.example) { newOnePassedFromWhatDoneInEDitView in
startingUser = newOnePassedFromWhatDoneInEDitView
print("✅ \(startingUser!.name)")
}
}
The reason Text is not showing you the updated user name that you are passing in the closure is, your startingUser property will be set to nil when you dismiss the sheet because you have bind that property with sheet. Now after calling callBackClosure(newData) you are calling dismiss() to dismiss the sheet. To overcome this issue you can try something like this.
struct ContentView: View {
#State private var startingUser: UserData?
#State private var updatedUser: UserData?
var body: some View {
VStack {
Text(updatedUser?.name ?? "no name")
Text("Create start user")
.onTapGesture {
startingUser = UserData(name: "Start User")
}
}
.sheet(item: $startingUser) { userToSend in
DetailView(user: userToSend) { newUser in
updatedUser = newUser
print("✅ \(updatedUser?.name ?? "no name")")
}
}
}
}
I would suggest you to read the Apple documentation of sheet(item:onDismiss:content:) and check the example from the Discussion section to get more understanding.
since a couple of days I try to find a solution for using the same view for both create and edit an CoreData object in SwiftUI.
Assume that we have a CoreData entity called Entry. And it only has one property name: String
Now we have a Main/Master view with a List of all Entry objects. To navigate to the DetailView I use the following code:
List {
ForEach(entires) { entry in
NavigationLink(destination: DetailView(entry: entry)) {
Text(item.name ?? "empty")
}
}
}
In this DetailView I can then edit the existing object:
struct DetailView: View {
#Environment(\.presentationMode) var presentationMode
#Environment(\.managedObjectContext) private var viewContext
#State var name: String = ""
#ObservedObject var entry: Entry
init(entry: Entry) {
self.entry = entry
self._name = State(initialValue: entry.name ?? "")
}
var body: some View {
NavigationView {
Form {
Section {
TextField("Name", text: $name)
Button("Save") {
guard name != "" else {return}
entry.name = name
do {
try viewContext.save()
print("saved")
} catch {
print(error.localizedDescription)
}
presentationMode.wrappedValue.dismiss()
}
}
Button("Cancel") {
presentationMode.wrappedValue.dismiss()
}.accentColor(.red)
}
.navigationTitle("Entry Name")
}
}
}
But then I need a different view which looks quite the same just for the new entry, since this view does not require a #ObservedObject. This view I access via a simple add button from the Main/Master view and it looks like this:
struct AddView: View {
#Environment(\.presentationMode) var presentationMode
#Environment(\.managedObjectContext) private var viewContext
#State var name: String = ""
var body: some View {
NavigationView {
Form {
TextField("Name", text: $name)
Button("Save") {
guard name != "" else {return}
let entry = Entry(context: viewContext)
entry.name = name
do {
try viewContext.save()
print("saved")
} catch {
print(error.localizedDescription)
}
presentationMode.wrappedValue.dismiss()
}
Button("Cancel") {
presentationMode.wrappedValue.dismiss()
}.accentColor(.red)
}
.navigationTitle("Add new Entry")
}
}
}
What I don't like here is that I have two views which are 99% equal except that one has the #ObservedObject and the other does not. How can I combine those two views into one? What I would need is something like a #ObservedObject var entry: Entry? where I can keep the Entry optional.
I have a view model which handles the loading of new data once the app launches and when a new item is added. I have an issue when it comes to showing new items when are added from a new view, for example, a sheet or even a NavigationLink.
View Model
class GameViewModel: ObservableObject {
//MARK: - Properties
#Published var gameCellViewModels = [GameCellViewModel]()
var game = [GameModel]()
init() {
loadData()
}
func loadData() {
if let retrievedGames = try? Disk.retrieve("games.json", from: .documents, as: [GameModel].self) {
game = retrievedGames
}
self.gameCellViewModels = game.map { game in
GameCellViewModel(game: game)
}
print("Load--->",gameCellViewModels.count)
}
func addNew(game: GameModel){
self.game.append(game)
saveData()
loadData()
}
private func saveData() {
do {
try Disk.save(self.game, to: .documents, as: "games.json")
}
catch let error as NSError {
fatalError("""
Domain: \(error.domain)
Code: \(error.code)
Description: \(error.localizedDescription)
Failure Reason: \(error.localizedFailureReason ?? "")
Suggestions: \(error.localizedRecoverySuggestion ?? "")
""")
}
}
}
View to load the ViewModel data, leading add button is able to add and show data but the trailing which opens a new View does not update the view. I have to kill the app to get the new data.
NavigationView{
List {
ForEach(gameList.gameCellViewModels) { gameList in
CellView(gameCellViewModel: gameList)
}
}.navigationBarTitle("Games Played")
.navigationBarItems(leading: Text("Add").onTapGesture {
let arr:[Int] = [1,2,3]
self.gameList.addNew(game: GameModel(game: arr))
}, trailing: NavigationLink(destination: ContentView()){
Text("Play")
})
}
Play View sample
#State var test = ""
var body: some View {
VStack(){
TextField("Enter value", text: $test)
.keyboardType(.numberPad)
Button(action: {
var arr:[Int] = []
arr.append(Int(self.test)!)
self.gameList.addNew(game: GameModel(game: arr))
}) {
Text("Send")
}
}
}
To what I can see the issue seems to be here:
List {
// Add id: \.self in order to distinguish between items
ForEach(gameList.gameCellViewModels, id: \.self) { gameList in
CellView(gameCellViewModel: gameList)
}
}
ForEach needs something to orientate itself on in order to know what elements are already displayed and which are not.
If this did not solve the trick. Please update the code you provided to Create a minimal, Reproducible Example