Inside core data I'm using Int16, but using picker with Int16 doesn't work.
Does anyone know why?
The work around I'm using is to create a model to manage values in Int, during the saving, I transform values in Int16.
struct PikHeiVIEW: View {
#Binding var height:Int
#Binding var heightInt16:Int16
var body: some View {
VStack {
Picker("", selection: $height) {
ForEach(150...190, id: \.self) {
Text("\($0)")
}
}
Text("You selected: \(height)")
Picker("", selection: $heightInt16) {
ForEach(150...190, id: \.self) {
Text("\($0)")
}
}
Text("You selected: \(heightInt16)")
}
}
}
struct TESTVIEW: View {
#State private var height:Int = 180
#State private var heightInt16:Int16 = 180
var body: some View {
PikHeiVIEW(height: $height, heightInt16: $heightInt16)
}
}
struct TESTVIEW_Previews: PreviewProvider {
static var previews: some View {
NavigationView {
TESTVIEW()
}
}
}
You can create your picker range using Int16
Picker("", selection: $heightInt16) {
ForEach(Int16(150)...Int16(190), id: \.self) {
Text("\($0)")
}
}
Related
I have 2 Views in my Swift Project and when I click on the Button on the secondView, I want to update the List in the First View. I don't know how to do it! If I use a static variable in my MainView and then edit this variable from the secondView, it works, but it won't update. And if I don't use static and instead use #State, it would update, but I can't access it from my secondView.
Here is the Code below:
import SwiftUI
struct ContentView: View {
var body: some View {
TabView {
MainView()
.tabItem() {
VStack {
Image(systemName: "circle.fill")
Text("MainView")
}
}.tag(0)
UpdateOtherViewFromHere()
.tabItem() {
VStack {
Image(systemName: "circle.fill")
Text("SecondView")
}
}.tag(1)
}
}
}
struct MainView: View {
var arrayList: [CreateListItems] = []
init() {
let a = CreateListItems(name: "First Name!")
let b = CreateListItems(name: "Second Name!")
let c = CreateListItems(name: "Third Name!")
arrayList.append(a)
arrayList.append(b)
arrayList.append(c)
}
var body: some View {
return VStack {
ZStack {
NavigationView {
List {
ForEach(arrayList) { x in
Text("\(x.name)")
}
}.navigationBarTitle("Main View")
}
}
}
}
}
struct UpdateOtherViewFromHere: View {
func updateList() {
//Code that should remove "FirstName" from the List in MainView
}
var body: some View {
return VStack {
Button(action: {
updateList()
}) {
Image(systemName: "heart.slash")
.font(.largeTitle)
Text("Click Me!")
}
}
}
}
struct CreateListItems: Identifiable {
var id: UUID = UUID()
var name: String
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
You can share it using #State and #Binding if you put
struct ContentView: View {
#State var arrayList: [CreateListItems] = []
struct MainView: View {
#Binding var arrayList: [CreateListItems]
struct UpdateOtherViewFromHere: View {
#Binding var arrayList: [CreateListItems]
or you use the MVVM pattern and store the list in an ObservableObject and use #StateObject/#ObservedObject (source) and use #EnvironmentObject(connection) to share it between your Views.
https://developer.apple.com/documentation/swiftui/managing-model-data-in-your-app
class ParentViewModel: ObservableObject{
#Published var arrayList: [CreateListItems] = []
init(){
addSamples()
}
func addSamples() {
let a = CreateListItems(name: "First Name!")
let b = CreateListItems(name: "Second Name!")
let c = CreateListItems(name: "Third Name!")
arrayList.append(a)
arrayList.append(b)
arrayList.append(c)
}
func updateList() {
let a = CreateListItems(name: "\(arrayList.count + 1) Name!")
arrayList.append(a)
}
}
struct ParentView: View {
#StateObject var vm: ParentViewModel = ParentViewModel()
var body: some View {
TabView {
MainView().environmentObject(vm)
.tabItem() {
VStack {
Image(systemName: "circle.fill")
Text("MainView")
}
}.tag(0)
UpdateOtherViewFromHere().environmentObject(vm)
.tabItem() {
VStack {
Image(systemName: "circle.fill")
Text("SecondView")
}
}.tag(1)
}
}
}
struct MainView: View {
#EnvironmentObject var vm: ParentViewModel
var body: some View {
return VStack {
ZStack {
NavigationView {
List {
ForEach(vm.arrayList) { x in
Text(x.name)
}
}.navigationBarTitle("Main View")
}
}
}
}
}
struct UpdateOtherViewFromHere: View {
#EnvironmentObject var vm: ParentViewModel
var body: some View {
return VStack {
Button(action: {
vm.updateList()
}) {
Image(systemName: "heart.slash")
.font(.largeTitle)
Text("Click Me!")
}
}
}
}
I get this error every time I launch a secondary picker.
The first picker works okay.
However when I switch pickers & scroll, I get the following:
Here is my entire code (written as a test of this problem):
import SwiftUI
struct ContentView: View {
#State private var selectedItem = 0
#State private var isMainPickerHidden = false
#State private var isSecondaryPickerHidden = true
var colors = ["Red", "Green", "Blue", "Tartan"]
var sizes = ["Tiny", "Small", "Medium", "Large", "Super Size"]
var body: some View {
ZStack {
Color.yellow.edgesIgnoringSafeArea(.all)
ZStack {
VStack {
Picker(selection: $selectedItem, label: Text("Please choose a color")) {
ForEach(colors.indices, id: \.self) {
Text(self.colors[$0])
}
}.hiddenConditionally(isHidden: isMainPickerHidden)
Text("You selected: \(colors[selectedItem])")
.hiddenConditionally(isHidden: isMainPickerHidden)
}
VStack {
Picker(selection: $selectedItem, label: Text("Please choose a size")) {
ForEach(sizes.indices, id: \.self) {
Text(self.sizes[$0])
}
}.hiddenConditionally(isHidden: isSecondaryPickerHidden)
Text("You selected: \(sizes[selectedItem])")
.hiddenConditionally(isHidden: isSecondaryPickerHidden)
Spacer()
Button(action: {
isSecondaryPickerHidden = !isSecondaryPickerHidden
isMainPickerHidden = !isMainPickerHidden
}) {
Text("Switch Pickers")
}.padding()
}
}
}
}
}
// =========================================================================================================
extension View {
func hiddenConditionally(isHidden: Bool) -> some View {
isHidden ? AnyView(hidden()) : AnyView(self)
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
What is the correct syntax for the ForEach{} to avoid this problem?
This is because you use the same selectedItem for both pickers.
If in the second picker you select the last item (index 4) and then you switch to the first picker (max index = 3), then in this line:
Text("You selected: \(colors[selectedItem])")
you'll try accessing the index which is out of range.
To fix this you can use a separate #State variable for each picker:
struct ContentView: View {
#State private var selectedColorIndex = 0
#State private var selectedSizeIndex = 0
Picker(selection: $selectedColorIndex, label: Text("Please choose a color")) {
Picker(selection: $selectedSizeIndex, label: Text("Please choose a size")) {
Newbie here.
My problem simplified:
I have a Person struct consisting of 2 strings - first and last name.
An initial array with a few persons (ex. "Bob" "Smith", "Joe" "Johnson", etc.)
A list view showing each member.
Clicking on a row in the list shows a detail view - call it "person card" view - which shows the first name and last name.
I then have a modal view to edit these variables.
Currently the Save button on the modal only closes the modal. However, because I am using bindings on the modal view to the values on the "person card" view, the "person card" view is updated with the changed data when the modal closes.
The list view though still shows the original value(s) and not the updated data (as I expect). I know that I have to add as method to the save function but I'm not sure what. I know how to insert and append to an array but I can't find an update array method.
FYI - The data model I am using is a "store" instance of a class that is an ObservableObject. I have that variable declared as an EnvironmentObject on each view.
Here is the code as requested:
struct PatientData: Identifiable
{
let id = UUID()
var patientName: String
var age: String
}
let patientDataArray: [PatientData] =
[
PatientData(patientName: "Charles Brown", age: "68"),
PatientData(patientName: "Jim Morrison", age: "36"),
]
final class PatientDataController: ObservableObject
{
#Published var patients = patientDataArray
{
struct PatientList: View
{
#EnvironmentObject var patientDataController: PatientDataController
#State private var showModalSheet = false
var body: some View
{
NavigationView
{
List
{
ForEach(patientDataController.patients)
{ patientData in NavigationLink(destination: PatientInfoCard(patientData: patientData))
{ PatientListCell(patientData: patientData) }
}
.onMove(perform: move)
.onDelete(perform: delete)
.navigationBarTitle(Text("Patient List"))
}
struct PatientInfoCard: View
{
#EnvironmentObject var patientDataController: PatientDataController
#State var patientData: PatientData
#State private var showModalSheet = false
var body: some View
{
VStack(alignment: .leading, spacing: 8)
{ // Change to patientDataArray???
Text(patientData.patientName)
.font(.largeTitle)
BasicInfo(patientData: patientData)
Spacer()
.frame(minWidth: 0, maxWidth: .infinity)
}
.padding()
// Can't push Edit button more than once
.navigationBarItems(trailing: Button(action:
{self.showModalSheet = true})
{Text("Edit")})
.sheet(isPresented: $showModalSheet)
{
EditPatientModal(patientData: self.$patientData, showModalSheet: self.$showModalSheet)
.environmentObject(self.patientDataController)
}
}
}
struct EditPatientModal: View
{
#Environment(\.presentationMode) var presentationMode
#EnvironmentObject var patientDataController: PatientDataController
#Binding var patientData: PatientData
#Binding var showModalSheet: Bool
var body: some View
{
NavigationView
{
VStack(alignment: .leading)
{
Text("Name")
.font(.headline)
TextField("enter name", text: $patientData.patientName)
Text("Age")
.font(.headline)
TextField("enter age", text: $patientData.age)
}
.navigationBarTitle(Text("Edit Patient"), displayMode: .inline)
.navigationBarItems(
leading: Button("Cancel")
{ self.cancel() },
trailing: Button("Save")
{ self.save() } )
}
}
private func save()
{
self.presentationMode.wrappedValue.dismiss()
}
Here is my updated code:
class PatientData: ObservableObject, Identifiable
{
let id = UUID()
#Published var patientName = ""
#Published var age = ""
init(patientName: String, age: String)
{
self.patientName = patientName
self.age = age
}
}
let patientDataArray: [PatientData] =
[
PatientData(patientName: "Charles Brown", age: "68"),
PatientData(patientName: "Jim Morrison", age: "36")
]
final class PatientDataController: ObservableObject
{
#Published var patients = patientDataArray
}
struct PatientList: View
{
#EnvironmentObject var patientDataController: PatientDataController
#EnvironmentObject var patientData: PatientData
#State private var showModalSheet = false
var body: some View
{
NavigationView
{
List
{
ForEach(self.patientDataController.patients.indices)
{ idx in
NavigationLink(destination: PatientInfoCard(patientData: self.$patientDataController.patients[idx]))
/*Cannot convert value of type 'Binding<PatientData>' to expected argument type 'PatientData'*/ <-- My one error message; in NavigationLink
{ PatientListCell(patientData: self.$patientDataController.patients[idx]) }
}
.onMove(perform: move)
.onDelete(perform: delete)
.navigationBarTitle(Text("Patient List"))
}
.navigationBarItems(leading: EditButton())
struct PatientInfoCard: View
{
#EnvironmentObject var patientDataController: PatientDataController
#Binding var patientData: PatientData
#State private var showModalSheet = false
var body: some View
{
VStack(alignment: .leading, spacing: 8)
{
Text(patientData.patientName)
.font(.largeTitle)
BasicInfo(patientData: patientData)
Spacer()
.frame(minWidth: 0, maxWidth: .infinity)
}
.padding()
.navigationBarItems(trailing: Button(action:
{self.showModalSheet = true})
{Text("Edit")})
.sheet(isPresented: $showModalSheet)
{
EditPatientModal(patientData: self.$patientData, showModalSheet: self.$showModalSheet)
.environmentObject(self.patientDataController)
}
}
}
struct BasicInfo: View
{
#EnvironmentObject var patientDataController: PatientDataController
#State var patientData: PatientData
var patientDataIndex: Int
{
patientDataController.patients.firstIndex(where: { $0.id == patientData.id })!
}
var body: some View
{
VStack(alignment: .leading, spacing: 8)
{
Text("Age:")
.font(.headline)
Text(patientData.age)
.font(.subheadline)
.foregroundColor(.secondary)
}
}
}
struct EditPatientModal: View
{
#Environment(\.presentationMode) var presentationMode
#EnvironmentObject var patientDataController: PatientDataController
#Binding var patientData: PatientData
#Binding var showModalSheet: Bool
var body: some View
{
NavigationView
{
VStack(alignment: .leading)
{
Text("Name")
.font(.headline)
TextField("enter name", text: $patientData.patientName)
Text("Age")
.font(.headline)
TextField("enter age", text: $patientData.age)
}
.navigationBarTitle(Text("Edit Patient"), displayMode: .inline)
.navigationBarItems(
leading: Button("Cancel")
{ self.cancel() },
trailing: Button("Save")
{ self.save() } )
}
}
private func save()
{
self.presentationMode.wrappedValue.dismiss()
}
You are missing 2 things in your code.
Your struct needs to be ObservableObject otherwise any changes happen to it will not get effected and in order for it to be ObservableObject it has to be a class so first change:
class PatientData: ObservableObject, Identifiable
{
let id = UUID()
#Published var patientName: String
#Published var age: String
init(patientName: String, age: String) {
self.patientName = patientName
self.age = age
}
}
I understand you have an environmentObject which is publishing, but it's only publishing changes to the array, meaning adding or removing items but not to individual patientData objects.
2nd thing to change is in your forEach loop you need pass Patient as a Bind and in order to do that you have to loop through indices and then access the data through Bind
NavigationView
{
if(self.patientDataController.patients.count > 0) {
List {
ForEach(self.patientDataController.patients.enumerated().map({$0}), id:\.element.id) { idx, patient in
NavigationLink(destination: PatientInfoCard(patientData: self.$patientDataController.patients[idx])) {
Text(patient.patientName)
}
}
}
.navigationBarItems(leading: EditButton())
} else {
Text("List is empty")
}
}
Let us know if this doesn't work
I would like to create a Settings view using SwiftUI. I mainly took the official example from Apple about SwiftUI to realize my code. The settings view should have a toggle to whether display or not my favorites items.
For now I have a landmarks list and a settings view.
struct Landmark: Hashable, Codable, Identifiable {
var id: Int
var imageName: String
var title: String
var isFavorite: Bool
var description: String
enum CodingKeys: String, CodingKey {
case id, imageName, title, description
}
}
final class UserData: ObservableObject {
#Published var showFavoriteOnly: Bool = false
#Published var items: [Landmark] = landmarkData
#Published var showProfile: Bool = false
}
struct ItemList: View {
#EnvironmentObject var userData: UserData
#State var trailing: Bool = false
init() {
UITableView.appearance().separatorStyle = .none
}
var body: some View {
NavigationView {
List {
VStack {
CircleBadgeView(text: String(landmarkData.count), thickness: 2)
Text("Tutorials available")
}.frame(minWidth:0, maxWidth: .infinity)
ForEach(userData.items) { landmark in
if !self.userData.showFavoriteOnly || landmark.isFavorite {
ZStack {
Image(landmark.imageName)
.resizable()
.frame(minWidth: 0, maxWidth: .infinity)
.cornerRadius(10)
.overlay(ImageOverlay(text: landmark.title), alignment: .bottomTrailing)
Text(String(landmark.isFavorite))
NavigationLink(destination: TutorialDetailView(landmark: landmark)) {
EmptyView()
}.buttonStyle(PlainButtonStyle())
}
}
}
}.navigationBarTitle("Tutorials")
.navigationBarItems(trailing: trailingItem())
}
}
}
extension ItemList {
func trailingItem () -> some View {
return HStack {
if userData.showProfile {
NavigationLink(destination: ProfileView()) {
Image(systemName: "person.circle")
.imageScale(.large)
.accessibility(label: Text("Profile"))
}
}
NavigationLink(destination: SettingsView().environmentObject(userData)) {
Image(systemName: "gear")
.imageScale(.large)
.accessibility(label: Text("Settings"))
}
}
}
}
As you can see my SettingsView is accessible from navigationBarItems of my NavigationView. I don't know if it's the problem or not but when I put the Toggle inside the ListView it works as expected. But now when I trigger the toggle to enable only favorite my application crash instantly.
I've tried to trigger the Show profile toggle from SettingsView and it works.
struct SettingsView: View {
#EnvironmentObject var userData: UserData
var body: some View {
Form {
Section(header: Text("General")) {
Toggle(isOn: $userData.showProfile) {
Text("Show profile")
}
Toggle(isOn: $userData.showFavoriteOnly) {
Text("Favorites only")
}
}
Section(header: Text("UI")) {
Toggle(isOn: .constant(false)) {
Text("Dark mode")
}
NavigationLink(destination: Text("third")) {
Text("Third navigation")
}
}
}.navigationBarTitle(Text("Settings"), displayMode: .inline)
}
}
In brief, the crash appears in my SettingsView when I trigger the Show only favorite Toggle and then I try to go back to the previous view which is ItemListView
The only information I can get about the error is Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
You can find the whole project on my GitHub : https://github.com/Hurobaki/swiftui-tutorial
Some help would be really appreciated :)
Here is a minimal version of your example code, that works:
struct Landmark: Hashable, Codable, Identifiable {
var id: Int
var imageName: String
var title: String
var isFavorite: Bool
var description: String
}
final class UserData: ObservableObject {
#Published var showFavoriteOnly: Bool = false
#Published var items: [Landmark] = [
Landmark(id: 1, imageName: "a", title: "a", isFavorite: true, description: "A"),
Landmark(id: 2, imageName: "b", title: "b", isFavorite: false, description: "B")
]
}
struct ContentView: View {
#EnvironmentObject var userData: UserData
var body: some View {
NavigationView {
List(userData.items.filter { !userData.showFavoriteOnly || $0.isFavorite }) { landmark in
Text(String(landmark.isFavorite))
}
.navigationBarTitle("Tutorials")
.navigationBarItems(trailing: trailingItem())
}
}
func trailingItem () -> some View {
return HStack {
NavigationLink(destination: SettingsView()) {
Text("Settings")
}
}
}
}
struct SettingsView: View {
#EnvironmentObject var userData: UserData
var body: some View {
Form {
Section(header: Text("General")) {
Toggle(isOn: $userData.showFavoriteOnly) {
Text("Favorites only")
}
}
}.navigationBarTitle(Text("Settings"), displayMode: .inline)
}
}
I am trying to have a Picker that shows which option is currently selected.
Try out the following code which correctly selects the right option but the picker does not show which option is selected:
import SwiftUI
struct ContentView: View {
#State var selectedIndex: Int = 0
let strings: [String] = {
var strings: [String] = []
for i in 0..<10 {
strings.append("\(i)")
}
return strings
}()
var body: some View {
NavigationView {
VStack {
Form {
Picker(selection: $selectedIndex,
label: Text("Selected string: \(strings[selectedIndex])")) {
ForEach(0..<strings.count) {
Text(self.strings[$0]).tag($0)
}
}
}
}
.navigationBarTitle("Form Picker",
displayMode: NavigationBarItem.TitleDisplayMode.inline)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Anyone know what could be wrong? It's observed using Xcode 11.1 and iOS 13.1
I created the simple picker I call "ListPicker" which should fit the bill. I've written it so it works well in a Form; if you need it outside of a Form you will have to tinker with it. If you see any way to improve the code, please add a comment; this is still a learning experience for all of us.
// MARK: - LIST PICKER (PUBLIC)
struct ListPicker<Content: View>: View {
#Binding var selectedItem: Int
var label: () -> Content
var data: [Any]
var selectedLabel: String {
selectedItem >= 0 ? "\(data[selectedItem])" : ""
}
var body: some View {
NavigationLink(destination: ListPickerContent(selectedItem: self.$selectedItem, data: self.data)) {
ListPickerLabel(label: self.label, value: "\(self.selectedLabel)")
}
}
}
// MARK: - INTERNAL
private struct ListPickerLabel<Content: View>: View {
let label: () -> Content
let value: String
var body: some View {
HStack(alignment: .center) {
self.label()
Spacer()
Text(value)
.padding(.leading, 8)
}
}
}
private struct ListPickerContentItem: View {
let label: String
let index: Int
let isSelected: Bool
var body: some View {
HStack {
Text(label)
Spacer()
if isSelected {
Image(systemName: "checkmark")
.foregroundColor(.accentColor)
}
}.background(Color.white) // so the entire row is selectable
}
}
private struct ListPickerContent: View {
#Environment(\.presentationMode) var presentationMode
#Binding var selectedItem: Int
var data: [Any]
var body: some View {
List {
ForEach(0..<data.count) { index in
ListPickerContentItem(label: "\(self.data[index])", index: index, isSelected: index == self.selectedItem).onTapGesture {
self.selectedItem = index
self.presentationMode.wrappedValue.dismiss()
}
}
}
}
}
Then you can use it like this:
#State var selectedCar: Int = 0
let cars = ["Jaguar", "Audi", "BMW", "Land Rover"]
Form {
ListPicker(
selectedItem: self.$selectedCar,
label: {
Text("Cars")
},
data: self.cars
)
}