I can't implement var on struct View to class ObservableObject in swiftui
struct History: View {
var busId : String
#ObservedObject var historyData = getHistory()
var body: some View {
ZStack{
ScrollView(.vertical, showsIndicators: false){
VStack(alignment: .leading){
ForEach(historyDataSatu.data){i in
Text("Something")
}
}
}
}
}
class getHistory: ObservableObject {
#Published var data = [history]()
init() {
let db = Firestore.firestore().collection("Bus").document(busId)
// An error occurs when I implement busId into document(busId). Please help me.
}
}
}
struct history: Identifiable {
var id : String
var day : String
}
You can initiate your ObservedObject object historyData in init method like. hope it helps you
struct History: View {
var busId : String
#ObservedObject var historyData = getHistory(busId: "")
init() {
self.historyData = getHistory(busId: busId)
}
var body: some View {
ZStack{
ScrollView(.vertical, showsIndicators: false){
VStack(alignment: .leading){
ForEach(historyData.data) { i in
Text("Something")
}
}
}
}
}
}
class getHistory: ObservableObject {
#Published var data = [history]()
init(busId: String) {
let db = Firestore.firestore().collection("Bus").document(busId)
}
}
Related
having a problem with updating data in ObservedObject
here's the data MRE:
struct Property: Identifiable, Codable, Hashable {
var id = UUID()
var name : String = ""
var meters : [Meter] = [Meter(name: "electricity"), Meter(name: "water")]
}
struct Meter: Identifiable, Hashable, Codable {
var id = UUID()
var name : String = ""
}
class PropertyData: ObservableObject {
#Published var properties: [Property]
func save() {
let encoder = JSONEncoder()
if let encoded = try? encoder.encode(properties) {
UserDefaults.standard.set(encoded, forKey: "PropertyData")
}
}
init() {
if let properties = UserDefaults.standard.data(forKey: "PropertyData") {
let decoder = JSONDecoder()
if let decoded = try? decoder.decode([Property].self, from: properties) {
self.properties = decoded
return
}
}
self.properties = [
Property(name: "Saks /1", meters: [Meter(name: "electricity")]),
Property(name: "Saks /2", meters: [Meter(name: "electricity"), Meter(name: "water")]),
]
}
}
import SwiftUI
struct ContentView: View {
#ObservedObject var data = PropertyData()
var body: some View {
NavigationView {
List {
ForEach(data.properties, id:\.self) {property in
NavigationLink(destination: NavigationLinkView(data: data, property: property)) {
Text(property.name)
}
}
}
}
}
}
struct NavigationLinkView: View {
#ObservedObject var data : PropertyData
var property:Property
var body: some View {
TabView {
MetersView(data: data, property: property)
.tabItem{
VStack {
Image(systemName: "scroll")
Text("Utitity")
}
}
}
}
}
struct MetersView: View {
#ObservedObject var data: PropertyData
#State private var metersPage = 0
#State var property : Property
#State private var addMeters = false
var body: some View {
VStack {
HStack {
Picker("Meters", selection: $metersPage) {
ForEach (0 ..< property.meters.count, id:\.self) {index in
Text(property.meters[index].name)
}
}
.pickerStyle(SegmentedPickerStyle())
Button{
print(property.meters)
addMeters.toggle()
} label: {
Image(systemName: "gear")
}
}.padding()
Spacer()
}.sheet(isPresented: $addMeters){AddMetersView(data: data, property: $property)}
}
}
struct AddMetersView: View {
#ObservedObject var data : PropertyData
#Binding var property : Property
#State var newMeter: String = ""
#Environment(\.presentationMode) var presentationMode
var body: some View {
VStack {
Form{
Section {
TextField("Add another meter", text: $newMeter)
.autocapitalization(.none)
Button{
if newMeter != "" {
property.meters.append(Meter(name: newMeter))
data.save()
print(property.meters.count)
} } label: {
Text("Add a meter")
}
}
ForEach(0..<property.meters.count, id:\ .self) {index in
Text(property.meters[index].name)
}
Section() {
Button("That's enough"){
print(property.meters)
presentationMode.wrappedValue.dismiss()}
}
}
}
}
}
I cannot understand, why the meters, that I add on AddMetersView, do update the Meters page, but then just goes away as soon as I go to the ContentView.
Plus, in my app, if I add a property, it does stay, and it persists, but not the Meters
This is similar to your previous question. Change #State var property : Property to
It is all about the connections. You break them in a few places along the way I made some changes and put comments along the line.
import SwiftUI
struct MetersParentView: View {
//Change to StateObject
#StateObject var data = PropertyData()
var body: some View {
NavigationView {
List {
ForEach($data.properties, id:\.id) {$property in
NavigationLink(destination: NavigationLinkView(data: data, property: $property)) {
Text(property.name)
}
}
}
}
}
}
struct NavigationLinkView: View {
#ObservedObject var data : PropertyData
//Make Binding there is no connection without it
#Binding var property : Property
var body: some View {
TabView {
MetersView(data: data, property: $property)
.tabItem{
VStack {
Image(systemName: "scroll")
Text("Utitity")
}
}
}
}
}
struct MetersView: View {
#ObservedObject var data: PropertyData
#State var selectedMeter: Meter = .init()
//Change to Binding
//State is a source of truth, it breaks the connection
#Binding var property : Property
#State private var addMeters = false
var body: some View {
VStack {
HStack {
Picker("Meters", selection: $selectedMeter) {
//Use object not index
ForEach(property.meters, id:\.id) {meter in
//Tag adjustment
Text(meter.name).tag(meter as Meter)
}
}.onAppear(perform: {
selectedMeter = property.meters.first ?? Meter()
})
.pickerStyle(SegmentedPickerStyle())
Button{
print(property.meters)
addMeters.toggle()
} label: {
Image(systemName: "gear")
}
}.padding()
Spacer()
}.sheet(isPresented: $addMeters){
AddMetersView(data: data, property: $property)
}
}
}
struct AddMetersView: View {
#ObservedObject var data : PropertyData
#Binding var property : Property
#State var newMeter: String = ""
#Environment(\.presentationMode) var presentationMode
var body: some View {
VStack {
Form{
Section {
TextField("Add another meter", text: $newMeter)
.autocapitalization(.none)
Button{
if newMeter != "" {
print(property.meters.count)
property.meters.append(Meter(name: newMeter))
print(property.meters.count)
data.save()
print(property.meters.count)
}
} label: {
Text("Add a meter")
}
}
//Dont use index
ForEach(property.meters, id:\ .id) {meter in
Text(meter.name)
}
Section() {
Button("That's enough"){
print(property.meters)
presentationMode.wrappedValue.dismiss()}
}
}
}
}
}
struct MetersParentView_Previews: PreviewProvider {
static var previews: some View {
MetersParentView()
}
}
I have such a structure, this structure seems wrong to me as the approach I want to ask you. So when I want to use 2 models in 1 view, I have to put it in foreach in one view. This is what I want. Using the data I use in my user's profile on other pages I want. How should I do this? How do you guys do it?
Let me give an example for your better understanding:
I want to show my user's Username data on the Homepage, how should I do this?. In fact, after initializing my model once, I want to use it in other views. What is the right approach.
import SwiftUI
struct ContentView: View {
#StateObject var network = ProfileNetwork()
var body: some View {
TabView{
ProfileView().tabItem { Image(systemName: "house") }
ForEach(self.network.userprofile,id:\.id){a in
ShopView(profile_model: a)
}.tabItem { Image(systemName: "house") }
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
class ProfileNetwork : ObservableObject {
#Published var userprofile : [UserPRofile] = [UserPRofile(name: "Test", coin: 1, id: "dsa")]
}
struct ProfileView : View {
#StateObject var network = ProfileNetwork()
var body: some View {
ForEach(self.network.userprofile, id:\.id){ i in
ProfileViewModel(profile_model: i)
}
}
}
struct ProfileViewModel : View {
var profile_model : UserPRofile
var body: some View {
Text(self.profile_model.name)
}
}
struct UserPRofile : Decodable{
var name : String
var coin : Int
var id : String
}
class ShopeNetwork : ObservableObject {
#Published var shop : [ShopStore] = [ShopStore(id: "sda", image: "dasd", price: 100, name: "sda")]
}
struct ShopView : View {
#StateObject var network = ShopeNetwork()
var profile_model : UserPRofile
var body: some View {
ForEach(self.network.shop, id:\.id){ c in
ShopViewModel(shop_model: c, profile_model: profile_model)
}
}
}
struct ShopViewModel : View {
var shop_model : ShopStore
var profile_model : UserPRofile
var body: some View {
Text(profile_model.name)
Text(self.shop_model.name)
}
}
struct ShopStore : Decodable {
var id : String
var image : String
var price : Int
var name : String
}
A possible solution is to create an #EnvironmentObject and inject it at the root level:
class AppState: ObservableObject {
#Published var userProfile: UserPRofile?
}
#main
struct TestApp: App {
#StateObject private var appState = AppState()
var body: some Scene {
WindowGroup {
ContentView()
.environmentObject(appState)
}
}
}
struct ProfileView: View {
#EnvironmentObject private var appState: AppState // access as an `#EnvironmentObject`
#StateObject var network = ProfileNetwork()
var body: some View {
VStack {
ForEach(self.network.userprofile, id: \.id) { i in
ProfileViewModel(profile_model: i)
}
}
.onAppear {
appState.userProfile = network.userprofile.first // set `userProfile` globally
}
}
}
struct ShopView: View {
#EnvironmentObject private var appState: AppState // use it in any other view
...
Swift 5, iOS 14
Make the class a singleton so it becomes shareable easily.
class ProfileNetwork : ObservableObject {
#Published var userprofile : [UserPRofile] = [UserPRofile(name: "Test", coin: 1, id: "dsa")]
static var shared = ProfileNetwork()
}
And then refer to it with the shared handle.
struct ContentView: View {
#StateObject var network = ProfileNetwork.shared
var body: some View {
....
}
struct ProfileView : View {
#StateObject var network = ProfileNetwork.shared
var body: some View {
....
}
I have this code :
import SwiftUI
struct PlayButton: View {
#Binding var isClicked: Bool
var body: some View {
Button(action: {
self.isClicked.toggle()
}) {
Image(systemName: isClicked ? "checkmark.circle.fill" : "circle")
}
}
}
struct ContentView: View {
#State private var isPlaying: Bool = false
var players : [String] = ["Crown" , "King" , "Queen" , "Prince"]
var body: some View {
VStack {
ForEach(players, id: \.self) { player in
HStack {
Text(player)
PlayButton(isClicked: $isPlaying)
}
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I want to deselect all other previously selected buttons if i select a new one. For example , if i select King and select queen , then King is deselected. How can i do that
What i have done. I honestly could not come with a solution .
I understand this might look like a lot more code to provide the answer but my assumption is you are trying to make a real world app. A real world app should be testable and so my answer is coming from a place where you can test your logic separate from your UI. This solution allows you to use the data to drive what your view is doing from a model perspective.
import SwiftUI
class PlayerModel {
let name: String
var isSelected : Bool = false
init(_ name: String){
self.name = name
}
}
class AppModel: ObservableObject {
let players : [PlayerModel] = [PlayerModel("Crown") , PlayerModel("King") ,PlayerModel("Queen") ,PlayerModel("Prince")]
var activePlayerIndex: Int?
init(){
}
func selectPlayer(_ player: PlayerModel){
players.forEach{
$0.isSelected = false
}
player.isSelected = true
objectWillChange.send()
}
}
struct PlayButton: View {
let isSelected: Bool
let action : ()->Void
var body: some View {
Button(action: {
self.action()
}) {
Image(systemName: isSelected ? "checkmark.circle.fill" : "circle")
}
}
}
struct ContentView: View {
#ObservedObject var model = AppModel()
var body: some View {
VStack {
ForEach(model.players, id: \.name) { player in
HStack {
Text(player.name)
PlayButton(isSelected: player.isSelected, action: { self.model.selectPlayer(player) })
}
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
PlayerView()
}
}
For a single selection, at a time you can pass selectedData to PlayButton view
struct PlayButton: View {
#Binding var selectedData: String
var data: String
var body: some View {
Button(action: {
selectedData = data
}) {
Image(systemName: data == selectedData ? "checkmark.circle.fill" : "circle")
}
}
}
struct ContentView: View {
#State private var selectedPlayer: String = ""
private var players : [String] = ["Crown" , "King" , "Queen" , "Prince"]
var body: some View {
VStack {
ForEach(players.indices) { index in
let obj = players[index]
HStack {
Text(obj)
PlayButton(selectedData: $selectedPlayer, data: obj)
}
}
}
}
}
I am currently having trouble modifying a String value using a TextField. Here is my (simplified) code so far:
class GradeItem: ObservableObject {
#Published var name: String
#Published var scoredPoints: Double
#Published var totalPoints: Double
let isUserCreated: Bool
init(name: String, scoredPoints: Double, totalPoints: Double, isUserCreated: Bool) {
self.name = name
self.scoredPoints = scoredPoints
self.totalPoints = totalPoints
self.isUserCreated = isUserCreated
}
}
var courses: [Course] {
// initialization code...
}
struct GradeCalculatorView: View {
#State var selectedCourseIndex: Int = 0
var body: some View {
VStack {
// allows user to select a course:
ForEach(0 ..< courses.count) { i in
Button(action: {
self.selectedCourseIndex = i
}, label: {
Text(courses[i].name)
})
}
CourseView(course: courses[selectedCourseIndex])
}
}
}
struct CourseView: View {
#ObservedObject var course: Course // passed in from GradeCalculatorView
var body: some View {
VStack(alignment: .leading) {
Text(course.name)
ForEach(course.categories, id: \.name) { category in
GradeCategoryView(category: category)
}
}.padding(.leading).frame(alignment: .leading)
}
}
struct GradeCategoryView: View {
#ObservedObject var category: GradeCategory // passed in from CourseView
var body: some View {
VStack(alignment: HorizontalAlignment.leading) {
HStack {
Text(category.name)
Spacer()
}
ForEach(category.items, id:\.name) { item in
GradeItemRow(item: item)
}
}
}
}
struct GradeItemRow: View {
#ObservedObject var item: GradeItem // passed in from GradeCategoryView
var body: some View {
TextField("Item Name", text: $item.name)
}
}
I cannot seem to modify the GradeItem object's name using the TextField. When the TextField is edited, its text changes temporarily. However, when the GradeItemRow View is reloaded, it displays the GradeItem object's original name, rather than its updated name.
Would somebody please be able to help?
Thanks in advance
UPDATE: As per your requests, I have added more context to this sample code.
I know that this does not work, as when I attempt to modify a GradeItem's name with a TextField, it changes temporarily. However, when I select a different course and then the course I was initially on, the TextField displays the unmodified name value.
The following test works.
class GradeItem: ObservableObject {
#Published var name: String
#Published var scoredPoints: Double
#Published var totalPoints: Double
let isUserCreated: Bool
init(name: String, scoredPoints: Double, totalPoints: Double, isUserCreated: Bool) {
self.name = name
self.scoredPoints = scoredPoints
self.totalPoints = totalPoints
self.isUserCreated = isUserCreated
}
init() {
self.name = "gradeItem" + UUID().uuidString
self.scoredPoints = 0.0
self.totalPoints = 0.0
self.isUserCreated = false
}
}
class Course: ObservableObject {
#Published var name: String
#Published var categories: [GradeCategory]
init(name: String, categories: [GradeCategory]) {
self.name = name
self.categories = categories
}
init() {
self.name = "course_" + UUID().uuidString
self.categories = [GradeCategory]()
self.categories.append(GradeCategory())
}
}
class GradeCategory: ObservableObject {
#Published var name: String
#Published var items: [GradeItem]
init(name: String, items: [GradeItem]) {
self.name = name
self.items = items
}
init() {
self.name = "category_" + UUID().uuidString
self.items = [GradeItem]()
self.items.append(GradeItem())
}
}
struct GradeItemRow: View {
#ObservedObject var item: GradeItem // passed in from GradeCategoryView
var body: some View {
TextField("Item Name", text: $item.name).textFieldStyle(RoundedBorderTextFieldStyle())
}
}
struct GradeCategoryView: View {
#ObservedObject var category: GradeCategory // passed in from CourseView
var body: some View {
VStack(alignment: .leading) {
HStack {
Text(category.name)
Spacer()
}
ForEach(category.items, id: \.name) { item in
GradeItemRow(item: item)
}
}
}
}
struct CourseView: View {
#Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
#ObservedObject var course: Course // passed in from ContentView
var body: some View {
VStack(alignment: .leading) {
Button(action: {
self.presentationMode.wrappedValue.dismiss()
}, label: {
Text("done")
})
Spacer()
Text(course.name)
ForEach(course.categories, id: \.name) { category in
GradeCategoryView(category: category)
}
Spacer()
}.padding(.leading).frame(alignment: .leading)
}
}
struct ContentView: View {
#State var courses: [Course] = [Course(), Course()]
#State var selectedCourseIndex: Int = 0
#State var showCourse = false
var body: some View {
VStack {
ForEach(0 ..< courses.count) { i in
Button(action: {
self.selectedCourseIndex = i
self.showCourse = true
}, label: {
Text(self.courses[i].name)
})
}
}.sheet(isPresented: self.$showCourse) {
CourseView(course: self.courses[self.selectedCourseIndex])
}
}
}
I'm trying up dynamically add new rows to a Picker as follows:
class ViewModel: ObservableObject {
#Published private (set) var drinks = ["Tea", "Coffee", "Wine"]
func addDrink(_ drink: String) {
drinks.append(drink)
}
}
struct PickerTest: View {
#State private var selectedDrink = "Tea"
#State private var customDrink = ""
#ObservedObject private var viewModel = ViewModel()
var body: some View {
VStack {
HStack {
TextField("Enter a drink", text: $customDrink)
Spacer()
Button("Add") {
self.viewModel.addDrink(self.customDrink)
}
}
Picker("Drinks", selection: $selectedDrink) { // Removing the wrapping Picker works
ForEach(viewModel.drinks, id: \.self) { drink in
Text(drink)
}
}
}.padding().labelsHidden()
}
}
This doesn't work. If I remove the Picker wrapping the ForEach, the ForEach updates as expected.
Is there a way to update the Picker dynamically?
It looks like Pickers bug - I hope, that Apple fixes it in future releases of SwiftUI.
I found ugly (I really don't like it) workaround for this problem:
class ViewModel: ObservableObject {
#Published var selectedDrink = "Tea"
#Published var drinks = ["Tea", "Coffee", "Wine"]
#Published var drinksChanged = true
func addDrink(_ drink: String) {
drinks.append(drink)
drinksChanged.toggle()
}
}
struct DrinksPicker: View {
#ObservedObject var viewModel: ViewModel
var body: some View {
Picker("Drinks", selection: $viewModel.selectedDrink) {
ForEach(viewModel.drinks, id: \.self) { drink in
Text(drink)
}
}
}
}
struct PickerTest: View {
#State private var customDrink = ""
#ObservedObject private var viewModel = ViewModel()
var body: some View {
VStack {
HStack {
TextField("Enter a drink", text: $customDrink)
Spacer()
Button("Add") {
self.viewModel.addDrink(self.customDrink)
self.customDrink = ""
}
}
if viewModel.drinksChanged {
DrinksPicker(viewModel: viewModel)
} else {
DrinksPicker(viewModel: viewModel)
}
}.padding().labelsHidden()
}
}
You can also hide this if-else in some another container:
struct DrinksPickerContainer: View {
#ObservedObject var viewModel: ViewModel
var body: some View {
Group {
if viewModel.drinksChanged {
DrinksPicker(viewModel: viewModel)
} else {
DrinksPicker(viewModel: viewModel)
}
}
}
}
and then use only DrinksPickerContainer(viewModel: viewModel) in PickerTest