I have an iOS app in which user decides the objects in his view. for example if user clicks on tag button a tag button is displayed in his view
a sample sub view
struct CheckBox: View {
#State var title: String = "default"
#State var isChecked: Bool = false
var body: some View {
HStack {
Button(action: toggle)
{
HStack {
Image(systemName: isChecked ? "checkmark.square": "square")
.font(.system(size: 20))
TextField("",text: $title)
}
}
}
}
private func toggle()
{
self.isChecked = !self.isChecked
print(self)
}
}
struct CheckBox_Previews: PreviewProvider {
static var previews: some View {
CheckBox(title: "tested",isChecked: false)
}
}
now the main view
struct MainView: View {
#State var vlist : [AnyView]
ForEach(0..<vlist.count, id: \.self)
{ i in
vlist[i]
}
Image(systemName: "checklist")
.foregroundColor(Color.blue)
.onTapGesture {
addItem(item: "checklist")
}
private func addItem(item: String)
{
switch item
{
case "checklist" :
let newCheck = AnyView(CheckBox(title: "default", isChecked: false))
self.vlist.append(newCheck)
default:
break
}
}
}
now the saving part
let sk = try?NSKeyedArchiver.archivedData(withRootObject: vlist, requiringSecureCoding: false)
contextObject.skelton = (sk as NSObject? as! NSArray)
Here the AnyView Object array is vlist . Now I want to store this array in attribute of data model "skelton" of type transformable. tried NSKeyedArchiver and NSKeyedUnarchiver
to encode and decode but error raises
requires that 'AnyView' conform to 'NSCoding'
Any methods to store the
anyView
object array to core data ? later I have to push it to cloud kit
Related
I'm trying to make an app that is displaying lists with selections/checkmarks based on clicked NavigationLink. The problem I encountered is that my selections disappear when I go back to main view and then I go again inside the NavigationLink. I'm trying to save toggles value in UserDefaults but it's not working as expected. Below I'm pasting detailed and main content view.
Second view:
struct CheckView: View {
#State var isChecked:Bool = false
#EnvironmentObject var numofitems: NumOfItems
var title:String
var count: Int=0
var body: some View {
HStack{
ScrollView {
Toggle("\(title)", isOn: $isChecked)
.toggleStyle(CheckToggleStyle())
.tint(.mint)
.onChange(of: isChecked) { value in
if isChecked {
numofitems.num += 1
print(value)
} else{
numofitems.num -= 1
}
UserDefaults.standard.set(self.isChecked, forKey: "locationToggle")
}.onTapGesture {
}
.onAppear {
self.isChecked = UserDefaults.standard.bool(forKey: "locationToggle")
}
Spacer()
}.frame(maxWidth: .infinity,alignment: .topLeading)
}
}
}
Main view:
struct CheckListView: View {
#State private var menu = Bundle.main.decode([ItemsSection].self, from: "items.json")
var body: some View {
NavigationView{
List{
ForEach(menu){
section in
NavigationLink(section.name) {
VStack{
ScrollView{
ForEach(section.items) { item in
CheckView( title: item.name)
}
}
}
}
}
}
}.navigationBarHidden(true)
.navigationViewStyle(StackNavigationViewStyle())
.listStyle(GroupedListStyle())
.navigationViewStyle(StackNavigationViewStyle())
}
}
ItemsSection:
[
{
"id": "9DC6D7CB-B8E6-4654-BAFE-E89ED7B0AF94",
"name": "Africa",
"items": [
{
"id": "59B88932-EBDD-4CFE-AE8B-D47358856B93",
"name": "Algeria"
},
{
"id": "E124AA01-B66F-42D0-B09C-B248624AD228",
"name": "Angola"
}
Model:
struct ItemsSection: Codable, Identifiable, Hashable {
var id: UUID = UUID()
var name: String
var items: [CountriesItem]
}
struct CountriesItem: Codable, Equatable, Identifiable,Hashable {
var id: UUID = UUID()
var name: String
}
As allready stated in the comment you have to relate the isChecked property to the CountryItem itself. To get this to work i have changed the model and added an isChecked property. You would need to add this to the JSON by hand if the JSON allread exists.
struct CheckView: View {
#EnvironmentObject var numofitems: NumOfItems
//use a binding here as we are going to manipulate the data coming from the parent
//and pass the complete item not only the name
#Binding var item: CountriesItem
var body: some View {
HStack{
ScrollView {
//use the name and the binding to the item itself
Toggle("\(item.name)", isOn: $item.isChecked)
.toggleStyle(.button)
.tint(.mint)
// you now need the observe the isChecked inside of the item
.onChange(of: item.isChecked) { value in
if value {
numofitems.num += 1
print(value)
} else{
numofitems.num -= 1
}
}.onTapGesture {
}
Spacer()
}.frame(maxWidth: .infinity,alignment: .topLeading)
}
}
}
struct CheckListView: View {
#State private var menu = Bundle.main.decode([ItemsSection].self, from: "items.json")
var body: some View {
NavigationView{
List{
ForEach($menu){ // from here on you have to pass a binding on to the decendent views
// mark the $ sign in front of the property name
$section in
NavigationLink(section.name) {
VStack{
ScrollView{
ForEach($section.items) { $item in
//Pass the complete item to the CheckView not only the name
CheckView(item: $item)
}
}
}
}
}
}
}.navigationBarHidden(true)
.navigationViewStyle(StackNavigationViewStyle())
.listStyle(GroupedListStyle())
.navigationViewStyle(StackNavigationViewStyle())
}
}
Example JSON:
[
{
"id": "9DC6D7CB-B8E6-4654-BAFE-E89ED7B0AF94",
"name": "Africa",
"items": [
{
"id": "59B88932-EBDD-4CFE-AE8B-D47358856B93",
"name": "Algeria",
"isChecked": false
},
{
"id": "E124AA01-B66F-42D0-B09C-B248624AD228",
"name": "Angola",
"isChecked": false
}
]
}
]
Remarks:
The aproach with JSON and storing this in the bundle will prevent you from persisting the isChecked property between App launches. Because you cannot write to the Bundle from within your App. The choice will persist as long as the App is active but will be back to default as soon as you either reinstall or force quit it.
As already mentioned in the comment, I don'r see where you read back from UserDefaults, so whatever gets stored there, you don't read it. But even if so, each Toggle is using the same key, so you are overwriting the value.
Instead of using the #State var isChecked, which is used just locally, I'd create another struct item which gets the title from the json and which contains a boolean that gets initialized with false.
From what I understood, I assume a solution could look like the following code. Just a few things:
I am not sure how your json looks like, so I am not loading from a json, I add ItemSections Objects with a title and a random number of items (actually just titles again) with a function.
Instead of a print with the number of checked toggles, I added a text output on the UI. It shows you on first page the number of all checked toggles.
Instead of using UserDefaults I used #AppStorage.
To make that work you have to make Array conform to RawRepresentable you achieve that with the following code/extension (just add it once somewhere in your project)
Maybe you should thing about a ViewModel (e.g. ItemSectionViewModel), to load the data from the json and provide it to the views as an #ObservableObject.
The code for the views:
//
// CheckItem.swift
// CheckItem
//
// Created by Sebastian on 24.08.22.
//
import SwiftUI
struct ContentView: View {
var body: some View {
VStack() {
CheckItemView()
}
}
}
struct CheckItemView: View {
let testStringForTestData: String = "Check Item Title"
#AppStorage("itemSections") var itemSections: [ItemSection] = []
func addCheckItem(title: String, numberOfItems: Int) {
var itemArray: [Item] = []
for i in 0...numberOfItems {
itemArray.append(Item(title: "item \(i)"))
}
itemSections.append(ItemSection(title: title, items: itemArray))
}
func getSelectedItemsCount() -> Int{
var i: Int = 0
for itemSection in itemSections {
let filteredItems = itemSection.items.filter { item in
return item.isOn
}
i = i + filteredItems.count
}
return i
}
var body: some View {
NavigationView{
VStack() {
List(){
ForEach(itemSections.indices, id: \.self){ id in
NavigationLink(destination: ItemSectionDetailedView(items: $itemSections[id].items)) {
Text(itemSections[id].title)
}
.padding()
}
}
Text("Number of checked items: \(self.getSelectedItemsCount())")
.padding()
Button(action: {
self.addCheckItem(title: testStringForTestData, numberOfItems: Int.random(in: 0..<4))
}) {
Text("Add Item")
}
.padding()
}
}
}
}
struct ItemSectionDetailedView: View {
#Binding var items: [Item]
var body: some View {
ScrollView() {
ForEach(items.indices, id: \.self){ id in
Toggle(items[id].title, isOn: $items[id].isOn)
.padding()
}
}
}
}
struct ItemSection: Identifiable, Hashable, Codable {
var id: String = UUID().uuidString
var title: String
var items: [Item]
}
struct Item: Identifiable, Hashable, Codable {
var id: String = UUID().uuidString
var title: String
var isOn: Bool = false
}
Here the adjustment to work with #AppStorage:
extension Array: RawRepresentable where Element: Codable {
public init?(rawValue: String) {
guard let data = rawValue.data(using: .utf8),
let result = try? JSONDecoder().decode([Element].self, from: data)
else {
return nil
}
self = result
}
public var rawValue: String {
guard let data = try? JSONEncoder().encode(self),
let result = String(data: data, encoding: .utf8)
else {
return "[]"
}
return result
}
}
I am attempting to set up a SwiftUI weather app. when the user searches for a city name in the textfield then taps the search button, a NavigationLink list item should appear in the list. Then, the user should be able to click the navigation link and re-direct to a detail view. My goal is to have the searched navigation links to populate a list. However, my search cities are not populating in the list, and I'm not sure why. In ContentView, I setup a list with a ForEach function that passes in cityNameList, which is an instance of the WeatherViewModel. My expectation is that Text(city.title) should display as a NavigationLink list item. How should I configure the ContentView or ViewModel to populate the the list with NavigationLink list items? See My code below:
ContentView
import SwiftUI
struct ContentView: View {
// Whenever something in the viewmodel changes, the content view will know to update the UI related elements
#StateObject var viewModel = WeatherViewModel()
#State private var cityName = ""
var body: some View {
NavigationView {
VStack {
TextField("Enter City Name", text: $cityName).textFieldStyle(.roundedBorder)
Button(action: {
viewModel.fetchWeather(for: cityName)
cityName = ""
}, label: {
Text("Search")
.padding(10)
.background(Color.green)
.foregroundColor(Color.white)
.cornerRadius(10)
})
List {
ForEach(viewModel.cityWeather, id: \.id) { city in
NavigationLink(destination: DetailView(detail: viewModel)) {
HStack {
Text(city.cityWeather.name)
.font(.system(size: 32))
}
}
}
}
Spacer()
}
.navigationTitle("Weather MVVM")
}.padding()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
ViewModel
import Foundation
class WeatherViewModel: ObservableObject {
//everytime these properties are updated, any view holding onto an instance of this viewModel will go ahead and updated the respective UI
#Published var cityWeather: WeatherModel = WeatherModel()
func fetchWeather(for cityName: String) {
guard let url = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=\(cityName)&units=imperial&appid=<MyAPIKey>") else {
return
}
let task = URLSession.shared.dataTask(with: url) { data, _, error in
// get data
guard let data = data, error == nil else {
return
}
//convert data to model
do {
let model = try JSONDecoder().decode(WeatherModel.self, from: data)
DispatchQueue.main.async {
self.cityWeather = model
}
}
catch {
print(error)
}
}
task.resume()
}
}
Model
import Foundation
struct WeatherModel: Identifiable, Codable {
var id = UUID()
var name: String = ""
var main: CurrentWeather = CurrentWeather()
var weather: [WeatherInfo] = []
func firstWeatherInfo() -> String {
return weather.count > 0 ? weather[0].description : ""
}
}
struct CurrentWeather: Codable {
var temp: Float = 0.0
}
struct WeatherInfo: Codable {
var description: String = ""
}
DetailView
import SwiftUI
struct DetailView: View {
var detail: WeatherViewModel
var body: some View {
VStack(spacing: 20) {
Text(detail.cityWeather.name)
.font(.system(size: 32))
Text("\(detail.cityWeather.main.temp)")
.font(.system(size: 44))
Text(detail.cityWeather.firstWeatherInfo())
.font(.system(size: 24))
}
}
}
struct DetailView_Previews: PreviewProvider {
static var previews: some View {
DetailView(detail: WeatherViewModel.init())
}
}
try something like this example code, works well for me:
struct WeatherModel: Identifiable, Codable {
let id = UUID()
var name: String = ""
var main: CurrentWeather = CurrentWeather()
var weather: [WeatherInfo] = []
func firstWeatherInfo() -> String {
return weather.count > 0 ? weather[0].description : ""
}
}
struct CurrentWeather: Codable {
var temp: Float = 0.0
}
struct WeatherInfo: Codable {
var description: String = ""
}
struct ContentView: View {
// Whenever something in the viewmodel changes, the content view will know to update the UI related elements
#StateObject var viewModel = WeatherViewModel()
#State private var cityName = ""
var body: some View {
NavigationView {
VStack {
TextField("Enter City Name", text: $cityName).textFieldStyle(.roundedBorder)
Button(action: {
viewModel.fetchWeather(for: cityName)
cityName = ""
}, label: {
Text("Search")
.padding(10)
.background(Color.green)
.foregroundColor(Color.white)
.cornerRadius(10)
})
List {
ForEach(viewModel.cityNameList) { city in
NavigationLink(destination: DetailView(detail: city)) {
HStack {
Text(city.name).font(.system(size: 32))
}
}
}
}
Spacer()
}.navigationTitle("Weather MVVM")
}.navigationViewStyle(.stack)
}
}
struct DetailView: View {
var detail: WeatherModel
var body: some View {
VStack(spacing: 20) {
Text(detail.name).font(.system(size: 32))
Text("\(detail.main.temp)").font(.system(size: 44))
Text(detail.firstWeatherInfo()).font(.system(size: 24))
}
}
}
class WeatherViewModel: ObservableObject {
#Published var cityNameList = [WeatherModel]()
func fetchWeather(for cityName: String) {
guard let url = URL(string: "https://api.openweathermap.org/data/2.5/weather?q=\(cityName)&units=imperial&appid=YOURKEY") else { return }
let task = URLSession.shared.dataTask(with: url) { data, _, error in
guard let data = data, error == nil else { return }
do {
let model = try JSONDecoder().decode(WeatherModel.self, from: data)
DispatchQueue.main.async {
self.cityNameList.append(model)
}
}
catch {
print(error) // <-- you HAVE TO deal with errors here
}
}
task.resume()
}
}
I have 3 views. Content View, TrainingView and TrainingList View. I want to list exercises from Core Data but also I want to make some changes without changing data.
In ContentView; I am trying to fetch data with CoreData
struct ContentView: View {
// MARK: - PROPERTY
#FetchRequest(
sortDescriptors: [NSSortDescriptor(keyPath: \Training.timestamp, ascending: false)],
animation: .default)
private var trainings: FetchedResults<Training>
#State private var showingAddProgram: Bool = false
// FETCHING DATA
// MARK: - FUNCTION
// MARK: - BODY
var body: some View {
NavigationView {
Group {
VStack {
HStack {
Text("Your Programs")
Spacer()
Button(action: {
self.showingAddProgram.toggle()
}) {
Image(systemName: "plus")
}
.sheet(isPresented: $showingAddProgram) {
AddProgramView()
}
} //: HSTACK
.padding()
List {
ForEach(trainings) { training in
TrainingListView(training: training)
}
} //: LIST
Spacer()
} //: VSTACK
} //: GROUP
.navigationTitle("Good Morning")
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
Button(action: {
print("test")
}) {
Image(systemName: "key")
}
}
} //: TOOLBAR
.onAppear() {
}
} //: NAVIGATION
}
private func showId(training: Training) {
guard let id = training.id else { return }
print(id)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView().environment(\.managedObjectContext, PersistenceController.preview.container.viewContext)
}
}
In TrainingView; I am getting exercises as a array list and I am pushing into to TrainingListView.
import SwiftUI
struct TrainingView: View {
#Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
#State var training: Training
#State var exercises: [Exercise]
#State var tempExercises: [Exercise] = [Exercise]()
#State var timeRemaining = 0
#State var timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
#State var isTimerOn = false
var body: some View {
VStack {
HStack {
Text("\(training.name ?? "")")
Spacer()
Button(action: {
presentationMode.wrappedValue.dismiss()
}) {
Text("Finish")
}
}
.padding()
ZStack {
Circle()
.fill(Color.blue)
.frame(width: 250, height: 250)
Circle()
.fill(Color.white)
.frame(width: 240, height: 240)
Text("\(timeRemaining)s")
.font(.system(size: 100))
.fontWeight(.ultraLight)
.onReceive(timer) { _ in
if isTimerOn {
if timeRemaining > 0 {
timeRemaining -= 1
} else {
isTimerOn.toggle()
stopTimer()
removeExercise()
}
}
}
}
Button(action: {
startResting()
}) {
if isTimerOn {
Text("CANCEL")
} else {
Text("GIVE A BREAK")
}
}
Spacer()
ExerciseListView(exercises: $tempExercises)
}
.navigationBarHidden(true)
.onAppear() {
updateBigTimer()
}
}
private func startResting() {
tempExercises = exercises
if let currentExercise: Exercise = tempExercises.first {
timeRemaining = Int(currentExercise.rest)
startTimer()
isTimerOn.toggle()
}
}
private func removeExercise() {
if let currentExercise: Exercise = tempExercises.first {
if Int(currentExercise.rep) == 1 {
let index = tempExercises.firstIndex(of: currentExercise) ?? 0
tempExercises.remove(at: index)
} else if Int(currentExercise.rep) > 1 {
currentExercise.rep -= 1
let index = tempExercises.firstIndex(of: currentExercise) ?? 0
tempExercises.remove(at: index)
tempExercises.insert(currentExercise, at: index)
}
updateBigTimer()
}
}
private func updateBigTimer() {
timeRemaining = Int(tempExercises.first?.rest ?? 0)
}
private func stopTimer() {
timer.upstream.connect().cancel()
}
private func startTimer() {
timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
}
}
struct TrainingView_Previews: PreviewProvider {
static var previews: some View {
TrainingView(training: Training(), exercises: [Exercise]())
}
}
In TrainingListView; I am listing all exercises.
struct TrainingListView: View {
#ObservedObject var training: Training
#Environment(\.managedObjectContext) private var managedObjectContext
var body: some View {
NavigationLink(destination: TrainingView(training: training, exercises: training.exercises?.toArray() ?? [Exercise]())) {
HStack {
Text("\(training.name ?? "")")
Text("\(training.exercises?.count ?? 0) exercises")
}
}
}
}
Also, I am adding video: https://twitter.com/huseyiniyibas/status/1388571724346793986
What I want to do is, when user taps any Training Exercises List should refreshed. It should be x5 again like in the beginning.
I had a hard time understanding your question but I guess I got the idea.
My understanding is this:
You want to store the rep count in the Core Data. (Under Training > Exercises)
You want to count down the reps one by one as the user completes the exercise.
But you don't want to change the original rep count stored in the Core Data.
I didn't run your code since I didn't want to recreate all the models and Core Data files. I guess I've spotted the problem. Here I'll explain how you can solve it:
The Core Data models are classes (reference types). When you pass around the classes (as you do in your code) and change their properties, you change the original data. In your case, you don't want that.
(Btw, being a reference type is a very useful and powerful property of classes. Structs and enums are value types, i.e. they are copied when passed around. The original data is unchanged.)
You have several options to solve your problem:
Just generate a different struct (something like ExerciseDisplay) from Exercise, and pass ExerciseDisplay to TrainingView.
You can write an extension to Exercise and "copy" the model before passing it to TrainingView. For this you'll need to implement the NSCopying protocol.
extension Exercise: NSCopying {
func copy(with zone: NSZone? = nil) -> Any {
return Exercise(...)
}
}
But before doing this I guess you'll need to change the Codegen to Manual/None of your entry in your .xcdatamodeld file. This is needed when you want to create the attributes manually. I'm not exactly sure how you can implement NSCopying for a CoreDate model, but it's certainly doable.
The first approach is easier but kinda ugly. The second is more versatile and elegant, but it's also more advanced. Just try the first approach first and move to the second once you feel confident.
Update:
This is briefly how you can implement the 1st approach:
struct ExerciseDisplay: Identifiable, Equatable {
public let id = UUID()
public let name: String
public var rep: Int
public let rest: Int
}
struct TrainingView: View {
// Other properties and states etc.
let training: Training
#State var exercises: [ExerciseDisplay] = []
init(training: Training) {
self.training = training
}
var body: some View {
VStack {
// Views
}
.onAppear() {
let stored: [Exercise] = training.exercises?.toArray() ?? []
self.exercises = stored.map { ExerciseDisplay(name: $0.name ?? "", rep: Int($0.rep), rest: Int($0.rest)) }
}
}
}
I have a SwiftUI app with SwiftUI App lifecycle that includes a master-detail type
list driven from CoreData. I have the standard list in ContentView and NavigationLinks
to the DetailView. I pass a Core Data entity object to the Detailview.
My struggle is setting-up bindings to TextFields in the DetailView for data entry
and for editing. I tried to create an initializer which I could not make work. I have
only been able to make it work with the following. Assigning the initial values
inside the body does not seem like the best way to do this, though it does work.
Since the Core Data entities are ObservableObjects I thought I should be able to
directly access and update bound variables, but I could not find any way to reference
a binding to Core Data in a ForEach loop.
Is there a way to do this that is more appropriate than my code below?
Simplified Example:
struct DetailView: View {
var thing: Thing
var count: Int
#State var localName: String = ""
#State private var localComment: String = ""
#State private var localDate: Date = Date()
//this does not work - cannot assign String? to State<String>
// init(t: Thing) {
// self._localName = t.name
// self._localComment = t.comment
// self._localDate = Date()
// }
var body: some View {
//this is the question - is this safe?
DispatchQueue.main.async {
self.localName = self.thing.name ?? "no name"
self.localComment = self.thing.comment ?? "No Comment"
self.localDate = self.thing.date ?? Date()
}
return VStack {
Text("\(thing.count)")
.font(.title)
Text(thing.name ?? "no what?")
TextField("name", text: $localName)
Text(thing.comment ?? "no comment?")
TextField("comment", text: $localComment)
Text("\(thing.date ?? Date())")
//TextField("date", text: $localDate)
}.padding()
}
}
And for completeness, the ContentView:
struct ContentView: View {
#Environment(\.managedObjectContext) private var viewContext
#FetchRequest(sortDescriptors: [NSSortDescriptor(keyPath: \Thing.date, ascending: false)])
private var things : FetchedResults<Thing>
#State private var count: Int = 0
#State private var coverDeletedDetail = false
var body: some View {
NavigationView {
List {
ForEach(things) { thing in
NavigationLink(destination: DetailView(thing: thing, count: self.count + 1)) {
HStack {
Image(systemName: "gear")
.resizable()
.frame(width: 40, height: 40)
.onTapGesture(count: 1, perform: {
updateThing(thing)
})
Text(thing.name ?? "untitled")
Text("\(thing.count)")
}
}
}
.onDelete(perform: deleteThings)
if UIDevice.current.userInterfaceIdiom == .pad {
NavigationLink(destination: WelcomeView(), isActive: self.$coverDeletedDetail) {
Text("")
}
}
}
.navigationTitle("Thing List")
.navigationBarItems(trailing: Button("Add Task") {
addThing()
})
}
}
private func updateThing(_ thing: FetchedResults<Thing>.Element) {
withAnimation {
thing.name = "Updated Name"
thing.comment = "Updated Comment"
saveContext()
}
}
private func deleteThings(offsets: IndexSet) {
withAnimation {
offsets.map { things[$0] }.forEach(viewContext.delete)
saveContext()
self.coverDeletedDetail = true
}
}
private func addThing() {
withAnimation {
let newThing = Thing(context: viewContext)
newThing.name = "New Thing"
newThing.comment = "New Comment"
newThing.date = Date()
newThing.count = Int64(self.count + 1)
self.count = self.count + 1
saveContext()
}
}
func saveContext() {
do {
try viewContext.save()
} catch {
print(error)
}
}
}
And Core Data:
extension Thing {
#nonobjc public class func fetchRequest() -> NSFetchRequest<Thing> {
return NSFetchRequest<Thing>(entityName: "Thing")
}
#NSManaged public var comment: String?
#NSManaged public var count: Int64
#NSManaged public var date: Date?
#NSManaged public var name: String?
}
extension Thing : Identifiable {
}
Any guidance would be appreciated. Xcode 12.2 iOS 14.2
You already mentioned it. CoreData works great with SwiftUI.
Just make your Thing as ObservableObject
#ObservedObject var thing: Thing
and then you can pass values from thing as Binding. This works in ForEach aswell
TextField("name", text: $thing.localName)
For others - note that I had to use the Binding extension above since NSManagedObjects are optionals. Thus as davidev stated:
TextField("name", text: Binding($thing.name, "no name"))
And ObservedObject, not Observable
I'm working on a calorie-tracker app.
In my App, I can open the Detail side of some products, set the amount and add the product to the "Cart".
Later, I want to read out all collected datas from the array and show them an a short overview.
But this View won't be updated after making changer on the array.
Due to I storage the datas with the userDefaults, I always have to reopen the app to update the view. Only then, the hole array will be displayed.
My Class Cart:
import Foundation
struct Order: Equatable, Identifiable, Codable {
var id = UUID()
var product: Product
var modifier: Double
var date: Date
}
class Cart: ObservableObject {
#Published var orders = [Order]()
static let saveKey = "SavedData"
init() {
if let data = UserDefaults.standard.data(forKey: Self.saveKey) {
if let decoded = try? JSONDecoder().decode([Order].self, from: data) {
self.orders = decoded
}
} else {
self.orders = []
}
}
// save order
func save() {
if let encoded = try? JSONEncoder().encode(self.orders) {
UserDefaults.standard.set(encoded, forKey: Self.saveKey)
}
}
// add to order
func add(order: Order) {
self.orders.append(order)
print("product added to cart")
save()
}
// remove from order
func remove(order: Order) {
if let index = orders.firstIndex(of: order) {
orders.remove(at: index)
}
}
}
I made a View to apply the amount of any special product.
import SwiftUI
struct AmountView: View {
#EnvironmentObject var cart: Cart
#State private var textInput = ""
#State private var orderFinished = false
var product: Product
func StringDoubleConverter(text: String) -> String {
return String(format: "%.2f", Double(textInput.replacingOccurrences(of: ",", with: ".")) ?? 0)
}
var body: some View {
VStack {
Form {
Section(header: Text("Mengenangabe")) {
// input for the amount
AmountInputView(textInput: $textInput)
if !orderFinished {
Button("Hinzufügen", action: {
orderFinished = true
hideKeyboard()
// add product to the cart
self.cart.add(order: Order(product: product, modifier: Double(StringDoubleConverter(text: textInput))!, date: Date()))
})
.disabled(textInput == "")
.animation(.default)
} else {
Text("Wurde zum Logbuch hinzugefügt")
.foregroundColor(.blue)
}
}
productNutritionCollectionView(product: product, modifier: Double(StringDoubleConverter(text: textInput))!)
}
}
}
}
struct AmountView_Previews: PreviewProvider {
static var previews: some View {
AmountView(product: Product.exampleProduct).environmentObject(Cart())
}
}
Then, I want to display all products in the order in a logbook view using a Form and a ForEach lope.
struct LogbookView: View {
func deleteProducts(at offsets: IndexSet) {
cart.orders.remove(atOffsets: offsets)
cart.save()
}
#EnvironmentObject var cart: Cart
#State private var date = Date()
var body: some View {
NavigationView {
Form {
Section(header: Text("List")) {
ForEach(cart.orders) { order in
Text(order.product.name)
}
.onDelete(perform: { indexSet in
deleteProducts(at: indexSet)
})
}
}
.navigationBarTitle(Text("Logbuch"), displayMode: .automatic)
.navigationBarItems(trailing: DateView(date: $date))
}
}
}
struct LogbookView_Previews: PreviewProvider {
static var previews: some View {
LogbookView().environmentObject(Cart())
}
}
I'm using a AppTab View to navigate the app. Therefore, I changed the AppTab View in the main Struct to the default View with an environment object of Cart.
#main
struct KalorientrackerApp: App {
var body: some Scene {
WindowGroup {
AppTabView().environmentObject(Cart())
}
}
}
struct KalorientrackerApp_Previews: PreviewProvider {
static var previews: some View {
Text("Hello, World!")
}
}
I'm opening my AmountView using a .sheet
struct ProductDetailView: View {
#State private var showAmountView = false
let product: Product
var body: some View {
VStack {
// placeholder Image
Image(product.fullImage)
.clipShape(Circle())
.padding(.top, 5)
Spacer()
Form {
productNutritionCollectionView(product: product, modifier: 100)
}
}
// Titel for Navigation bar
.navigationBarTitle(Text(product.name), displayMode: .inline)
// Button to go to amount view
.navigationBarItems(trailing: Button(action: {
self.showAmountView = true
}, label: {
Image(systemName: "plus.circle")
.padding(.leading, 20)
}).sheet(isPresented: $showAmountView, content: {
AmountView(product: product).environmentObject(Cart())
}))
}
}
struct ProductDetailView_Previews: PreviewProvider {
static var previews: some View {
ProductDetailView(product: Product.exampleProduct) }
}
I already found some other discussions, but they didn't worked for me.
I'm using Xcode 12 beta 6 and iOS14 beta 6
I found the bug myself. The problem was, that I committed explicit an .environmentObject in my .sheet action.
AmountView(product: product).environmentObject(Cart())
I removed .environmentObject(Cart()) from the .sheet action. Now it's working.
Thinking this caused the bug because I'm using the .environmentObject(Cart()) operator in the main View of my project.