SwiftUI change list item when pressed - swiftui

Supposing I have a simple view with a list:
struct ContentView: View {
var names = ["Bob","John","Lisa"]
var body: some View {
List {
ForEach (names, id: \.self) {name in
Detail(name: name)
}
}
}
}
How would I achieve for the list item to change on press? The Detail would presumably look something like:
struct Detail: View {
var name: String
var body: some View {
if !inFocus {
Text(name)
} else {
Text("This is a detail view")
Text(name)
Text("---------------------")
}
}
}

ou can try a few things like this with #State variable
struct Detail: View {
var name: String
#State var inFocus = false
var body: some View {
if !inFocus {
Text(name)
.onTapGesture{
self.inFocus.toggle()
}
} else {
VStack{
Text("This is a detail view")
Text(name)
Text("---------------------")
}
.onTapGesture {
self.inFocus.toggle()
}
}
}
}

Related

Changing a TextField text for items in a foreach NavigationLink SwiftUI and saving it

There is a list in on the Main View that has navigation links that bring you to a an Edit Birthday View where the textFieldName is saved with the onAppear method. I need help in allowing the user to change the text in the text field on the Edit Birthday View and having it save when the user dismisses and returns to that particular item in the foreach list. I have tried onEditingChanged and on change method but they don't seem to work. (Also, in my view model i append birthday items when they are created in the Add Birthday View). If you would like to see more code i will make updates. Thank you.
/// MAIN VIEW
import SwiftUI
struct MainView: View {
#EnvironmentObject var vm: BirthdayViewModel
#State var nameTextField: String = ""
var body: some View {
VStack(spacing: 20) {
List {
ForEach(vm.searchableUsers, id: \.self) { birthday in
NavigationLink(destination: EditBirthdayView(birthday: birthday)) {
BirthdayRowView(birthday: birthday)
}
.listRowSeparator(.hidden)
}
.onDelete(perform: vm.deleteBirthday)
}
}
.toolbar {
ToolbarItem {
NavigationLink(destination: AddBirthdayView(textfieldName: $nameTextField)) {
Image(systemName: "plus.circle")
}
}
}
}
}
/// EDIT BIRTHDAY VIEW
import SwiftUI
import Combine
struct EditBirthdayView: View {
#EnvironmentObject var vm: BirthdayViewModel
#State var textfieldName: String = ""
#Environment(\.presentationMode) var presentationMode
var birthday: BirthdayModel
var body: some View {
NavigationView {
VStack {
TextField("Name...", text: $textfieldName)
}
Button {
saveButtonPressed()
} label: {
Text("Save")
}
}
.onAppear {
DispatchQueue.main.asyncAfter(deadline: .now()) {
textfieldName = birthday.name
}
}
}
}
func saveButtonPressed() {
vm.updateItem(birthday: birthday)
presentationMode.wrappedValue.dismiss()
}
func updateTextField() {
textfieldName = birthday.name
}
}
struct MainView: View {
#EnvironmentObject var store: BirthdayStore
var body: some View {
List {
ForEach($store.birthdays) { $birthday in
NavigationLink(destination: EditBirthdayView(birthday: $birthday)) {
BirthdayRowView(birthday: birthday)
}
}
.onDelete(perform: deleteBirthday)
}
.listRowSeparator(.hidden)
.toolbar {
ToolbarItem {
NavigationLink(destination: AddBirthdayView() {
Image(systemName: "plus.circle")
}
}
}
}
}
struct EditBirthdayView: View {
#EnvironmentObject var store: BirthdayStore
#Binding var birthday: Birthday
...
TextField("Name", text: $birthday.name)

#State var with array does not update view when grandchild updates it

I have 3 views. The issue I have is that the 1st one (a parent view of 2) is not changing when the 3rd one (a children of view 2) has updated a property in the array.
Let's use some code so it is easier to understand:
public struct Item {
public let id: String
public var name: String?
public var inStock: Bool
import SwiftUI
#main
struct ThisIsMessedUpApp: App {
var body: some Scene {
WindowGroup {
ItemsMainView()
}
}
}
import Foundation
import SwiftUI
struct ItemsMainView: View {
#State var items = [Item]()
var body: some View {
VStack {
Text("Item count is \(items.count)")
Divider()
VStack {
Text("ItemsMainView has:")
HStack {
ForEach(self.items, id: \.id) { item in
Text(item.name ?? "nothing found")
Spacer()
Text(item.inStock.description)
}
}
}
ItemsView(items: $items)
}
}
}
struct ItemsView: View {
#Binding var items: [Item]
var body: some View {
Button("Add new item (call made from ItemsView", action: {
self.items.append(Item(id: UUID().uuidString,
name: "Test #1",
inStock: false))
})
VStack {
ForEach($items, id: \.id) { $item in
ItemView(item: $item)
}
}
}
}
struct ItemView: View {
#Binding var item: Item
#State var draftItemName: String = ""
var body: some View {
Text("ItemView has")
HStack {
TextField("TextField", text: $draftItemName)
.onSubmit {
item.name = draftItemName
}
Spacer()
Text(item.inStock.description)
}
.onAppear {
draftItemName = item.name ?? ""
}
}
}
Some of the Text are for debugging purposes.
If you run this code and change the second TextField's value to, say, "Test #2", you will see that you end up with an inconsistent UI state: ItemsMainView has "Test #1", whereas ItemView has "Test #2"
In Xcode 14.2, create a new project for ios or macos. Copy and paste the following code, replacing
the original ContentView.
Tell us if this code, tested on real ios 16.3 devices (not Previews), macCatalyst and MacOS 13.2 only, works for you.
struct ContentView: View {
var body: some View {
ItemsMainView()
}
}
public struct Item {
public let id: String
public var name: String?
public var inStock: Bool
}
struct ItemsMainView: View {
#State var items = [Item]()
var body: some View {
VStack {
Text("Item count is \(items.count)")
Divider()
VStack {
Text("ItemsMainView has:")
ForEach(items, id: \.id) { item in
HStack {
Text(item.name ?? "nothing found").foregroundColor(.red)
Spacer()
Text(item.inStock.description).foregroundColor(.red)
}
}
}
ItemsView(items: $items)
}
}
}
struct ItemsView: View {
#Binding var items: [Item]
var body: some View {
Button("Add new item (call made from ItemsView", action: {
self.items.append(Item(id: UUID().uuidString, name: "Test #1", inStock: false))
}).buttonStyle(.bordered)
VStack {
ForEach($items, id: \.id) { $item in
ItemView(item: $item)
}
}
}
}
struct ItemView: View {
#Binding var item: Item
#State var draftItemName: String = ""
var body: some View {
Text("ItemView has")
HStack {
TextField("TextField", text: $draftItemName)
.onSubmit {
item.name = draftItemName
}
Spacer()
Text(item.inStock.description)
}
.onAppear {
draftItemName = item.name ?? ""
}
}
}

#EnvironmentObject bug in SwiftUI

When I press the Move button in the contextMenu, I change the isCopied and setOriginPath variables in the EnvironmentObject. When this change is made, the List view is cleared and I can't see anything on the screen. I don't have any problems when I don't use EnvironmentObject.
ContextMenu:
.contextMenu {
Button {
safeFileVM.hideSelectedFile(fileName: currentFile.fileName)
safeFileVM.takeArrayOfItems()
} label: {
HStack {
Text(!currentFile.isLock ? "Hide" : "Show")
Image(systemName: currentFile.isLock ? "eye" : "eye.slash")
}
}
Button {
safeFileClipboard.setOriginPath = URL(fileURLWithPath: currentFile.localPath)
safeFileClipboard.isCopied = true
} label: {
HStack {
Text("Move")
Image(systemName: "arrow.up.doc")
}
}
}
View:
struct DetailObjectView: View {
#ObservedObject var safeFileVM: SafeFileViewModel = SafeFileViewModel()
#EnvironmentObject var safeFileClipboard: SafeFileClipBoard
var currentFile: MyFile
var currentLocation = ""
var body: some View {
VStack {
.....
}
.contextMenu {
Button {
safeFileVM.hideSelectedFile(fileName: currentFile.fileName)
safeFileVM.takeArrayOfItems()
} label: {
HStack {
Text(!currentFile.isLock ? "Hide" : "Show")
Image(systemName: currentFile.isLock ? "eye" : "eye.slash")
}
}
Button {
safeFileClipboard.setOriginPath = URL(fileURLWithPath: currentFile.localPath)
safeFileClipboard.isCopied = true
} label: {
HStack {
Text("Move")
Image(systemName: "arrow.up.doc")
}
}
}
}
}
In the mini project below, when the EnvironmentObject value changes, navigation goes to the beginning. Why ? How can I fix this ?
Example Project:
Main:
#main
struct EnvironmentTestApp: App {
#StateObject var fooConfig: FooConfig = FooConfig()
var body: some Scene {
WindowGroup {
NavigationView {
ContentView()
.environmentObject(fooConfig)
}
}
}
}
ContentView:
struct ContentView: View {
#EnvironmentObject var fooConfig: FooConfig
private let numbers: [Number] = [.init(item: "1"), .init(item: "2"), .init(item: "3")]
var body: some View {
List {
ForEach(numbers, id: \.id) { item in
DetailView(itemNumber: item.item)
}
}
}
}
struct Number: Identifiable {
var id = UUID()
var item: String
}
DetailView:
struct DetailView: View {
#EnvironmentObject var fooConfig: FooConfig
var itemNumber: String = ""
var body: some View {
NavigationLink(destination: ContentView().environmentObject(fooConfig)) {
Text("\(itemNumber) - \(fooConfig.fooBool == true ? "On" : "Off")")
.environmentObject(fooConfig)
.contextMenu {
Button {
fooConfig.fooBool.toggle()
} label: {
HStack {
Text(fooConfig.fooBool != true ? "On" : "Off")
}
}
}
}
}
}
ObservableObject:
class FooConfig: ObservableObject {
#Published var fooBool: Bool = false
}
Move that from scene into ContentView, because scene is a bad place to update view hierarchy, it is better to do inside view hierarchy, so here
struct EnvironmentTestApp: App {
var body: some Scene {
WindowGroup {
ContentView() // only root view here !!
}
}
}
everything else is inside views, like
struct ContentView: View {
#StateObject private var foo = FooConfig()
var body: some View {
NavigationView {
MainView()
.environmentObject(foo) // << here !!
}
}
}
struct MainView: View {
#EnvironmentObject var fooConfig: FooConfig
private let numbers: [Number] = [.init(item: "1"), .init(item: "2"), .init(item: "3")]
var body: some View {
List {
ForEach(numbers, id: \.id) { item in
DetailView(itemNumber: item.item)
}
}
}
}
and so on...
Tested with Xcode 14 / iOS 16

NavigationLink dismisses after TextField changes

I have a navigation stack that's not quite working as desired.
From my main view, I want to switch over to a list view which for the sake of this example represents an array of strings.
I want to then navigate to a detail view, where I want to be able to change the value of the selected string.
I have 2 issues with below code:
on the very first keystroke within the TextField, the detail view is being dismissed
the value itself is not being changed
Also, I suppose there must be a more convenient way to do the binding in the detail view ...
Here's the code:
import SwiftUI
#main
struct TestApp: App {
var body: some Scene {
WindowGroup {
TestMainView()
}
}
}
struct TestMainView: View {
var body: some View {
NavigationView {
List {
NavigationLink("List View", destination: TestListView())
}
.navigationTitle("Test App")
}
}
}
struct TestListView: View {
#State var strings = [
"Foo",
"Bar",
"Buzz"
]
#State var selectedString: String? = nil
var body: some View {
List(strings.indices) { index in
NavigationLink(
destination: TestDetailView(selectedString: $selectedString),
tag: strings[index],
selection: $selectedString) {
Text(strings[index])
}
.navigationBarTitleDisplayMode(.inline)
.navigationTitle("List")
}
}
}
struct TestDetailView: View {
#Binding var selectedString: String?
var body: some View {
VStack {
if let _ = selectedString {
TextField("Placeholder",
text: Binding<String>( //what's a better solution here?
get: { selectedString! },
set: { selectedString = $0 }
)
)
.padding()
.textFieldStyle(RoundedBorderTextFieldStyle())
}
Spacer()
}
.navigationTitle("Detail")
}
}
struct TestMainView_Previews: PreviewProvider {
static var previews: some View {
TestMainView()
}
}
I am quite obviously doing it wrong, but I cannot figure out what to do differently...
You're changing the NavigationLink's selection from inside the NavigationLink which forces the TestListView to reload.
You can try the following instead:
struct TestListView: View {
#State var strings = [
"Foo",
"Bar",
"Buzz",
]
var body: some View {
List(strings.indices) { index in
NavigationLink(destination: TestDetailView(selectedString: self.$strings[index])) {
Text(self.strings[index])
}
}
}
}
struct TestDetailView: View {
#Binding var selectedString: String // remove optional
var body: some View {
VStack {
TextField("Placeholder", text: $selectedString)
.padding()
.textFieldStyle(RoundedBorderTextFieldStyle())
Spacer()
}
}
}

Save selected item in List

This looks like a very simple thing, but I can't figure out how to do this:
I have a List embedded in a NavigationView, containing a NavigationLink to view the detail of the item.
I have a save bar button where I would like to save the selected item. But how can I access the selected item?
It isn't visible in the button's action closure.
struct ItemList : View {
#EnvironmentObject var items: ItemsModel
var body: some View {
NavigationView {
List(items) { item in
NavigationLink(destination: ItemDetail(item: item)) {
Text(item.name)
}
}
.navigationBarTitle(Text("Item"))
.navigationBarItems(trailing: Button(action: {
self.save(/*item: item */) // How can I access item here?
}, label: {
Text("Save")
}))
}
}
func save(item: Item) {
print("Saving...")
}
}
Navigation links are not obligatory to accomplish this.
import SwiftUI
struct ContentView: View {
struct Ocean: Identifiable, Hashable {
let name: String
var id: Self { self }
}
private var oceans = [
Ocean(name: "Pacific"),
Ocean(name: "Atlantic"),
Ocean(name: "Indian"),
Ocean(name: "Southern"),
Ocean(name: "Arctic")
]
#State private var selectedOceans = [Ocean]()
#State private var multiSelection = Set<Ocean.ID>()
var body: some View {
VStack {
Text("Oceans")
List(oceans, selection: $multiSelection) {
Text($0.name)
}
.navigationTitle("Oceans")
.environment(\.editMode, .constant(.active))
.onTapGesture {
// Walkaround: try how it works without `asyncAfter()`
DispatchQueue.main.asyncAfter(deadline: .now() + 0.05, execute: {
selectedOceans = Array(multiSelection)
print(selectedOceans)
})
}
Divider()
Text("Selected oceans")
List(selectedOceans, selection: $multiSelection) {
Text($0.name)
}
}
Text("\(multiSelection.count) selections")
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}