Sheet inside ForEach doesn't loop over items SwiftUI - swift

I have an issue using a sheet inside a ForEach. Basically I have a List that shows many items in my array and an image that trigger the sheet. The problem is that when my sheet is presented it only shows the first item of my array which is "Harry Potter" in this case.
Here's the code
struct ContentView: View {
#State private var showingSheet = false
var movies = ["Harry potter", "Mad Max", "Oblivion", "Memento"]
var body: some View {
NavigationView {
List {
ForEach(0 ..< movies.count) { movie in
HStack {
Text(self.movies[movie])
Image(systemName: "heart")
}
.onTapGesture {
self.showingSheet = true
}
.sheet(isPresented: self.$showingSheet) {
Text(self.movies[movie])
}
}
}
}
}
}

There should be only one sheet, so here is possible approach - use another sheet modifier and activate it by selection
Tested with Xcode 12 / iOS 14 (iOS 13 compatible)
extension Int: Identifiable {
public var id: Int { self }
}
struct ContentView: View {
#State private var selectedMovie: Int? = nil
var movies = ["Harry potter", "Mad Max", "Oblivion", "Memento"]
var body: some View {
NavigationView {
List {
ForEach(0 ..< movies.count) { movie in
HStack {
Text(self.movies[movie])
Image(systemName: "heart")
}
.onTapGesture {
self.selectedMovie = movie
}
}
}
.sheet(item: self.$selectedMovie) {
Text(self.movies[$0])
}
}
}
}

I changed your code to have only one sheet and have the selected movie in one variable.
extension String: Identifiable {
public var id: String { self }
}
struct ContentView: View {
#State private var selectedMovie: String? = nil
var movies = ["Harry potter", "Mad Max", "Oblivion", "Memento"]
var body: some View {
NavigationView {
List {
ForEach(movies) { movie in
HStack {
Text(movie)
Image(systemName: "heart")
}
.onTapGesture {
self.selectedMovie = movie
}
}
}
.sheet(item: self.$selectedMovie, content: { selectedMovie in
Text(selectedMovie)
})
}
}
}

Wanted to give my 2 cents on the matter.
I was encountering the same problem and Asperi's solution worked for me.
BUT - I also wanted to have a button on the sheet that dismisses the modal.
When you call a sheet with isPresented you pass a binding Bool and so you change it to false in order to dismiss.
What I did in the item case is I passed the item as a Binding. And in the sheet, I change that binding item to nil and that dismissed the sheet.
So for example in this case the code would be:
var movies = ["Harry potter", "Mad Max", "Oblivion", "Memento"]
var body: some View {
NavigationView {
List {
ForEach(0 ..< movies.count) { movie in
HStack {
Text(self.movies[movie])
Image(systemName: "heart")
}
.onTapGesture {
self.selectedMovie = movie
}
}
}
.sheet(item: self.$selectedMovie) {
Text(self.movies[$0])
// My addition here: a "Done" button that dismisses the sheet
Button {
selectedMovie = nil
} label: {
Text("Done")
}
}
}
}

Related

SwiftUI: Dismisses View when Binding of List state changes

I have the following example in SwiftUI:
import SwiftUI
struct DetailView: View {
var element:Int
#Binding var favList:[Int]
var body: some View {
Button(action: {
if !favList.contains(element){
favList.append(element)
}
else{
favList.removeAll(where: {$0 == element})
}
}){
HStack {
Image(systemName: (favList.contains(element)) ? "star.slash" : "star")
Text((favList.contains(element)) ? "Remove from favorites" : "Add to favorites")
}
.frame(maxWidth: 300)
}
}
}
struct MainView: View {
let elements = [1,2,3,4]
#State var favList:[Int] = []
var body: some View {
NavigationView {
List{
if !favList.isEmpty{
Section("Favorits"){
ForEach(elements, id: \.self){element in
if favList.contains(element){
NavigationLink(destination: DetailView(element: element, favList: $favList)) {
Text("\(element)")
}
}
}
}
}
Section("All elements"){
ForEach(elements, id: \.self){element in
if !favList.contains(element){
NavigationLink(destination: DetailView(element: element, favList: $favList)) {
Text("\(element)")
}
}
}
}
}
}
}
}
If I change the favList in the DetailView the view gets automatically dismissed. I guess this because the List structure changes.
Am I doing something wrong? Is this the intended behavior? How can I avoid this?
Best regards
i tried with this, it's the same code just fixing the section header. using the fav button in the view doesn't dismiss the view
import SwiftUI
struct DetailView: View {
var element:Int
#Binding var favList:[Int]
var body: some View {
Button(action: {
if !favList.contains(element){
favList.append(element)
}
else{
favList.removeAll(where: {$0 == element})
}
}){
HStack {
Image(systemName: (favList.contains(element)) ? "star.slash" : "star")
Text((favList.contains(element)) ? "Remove from favorites" : "Add to favorites")
}
.frame(maxWidth: 300)
}
}
}
struct MainView: View {
let elements = [1,2,3,4]
#State var favList:[Int] = []
var body: some View {
NavigationView {
List{
if !favList.isEmpty{
Section(header:Text("Favorits")){
ForEach(elements, id: \.self){element in
if favList.contains(element){
NavigationLink(destination: DetailView(element: element, favList: $favList)) {
Text("\(element)")
}
}
}
}
}
Section(header:Text("Favorits")){
ForEach(elements, id: \.self){element in
if !favList.contains(element){
NavigationLink(destination: DetailView(element: element, favList: $favList)) {
Text("\(element)")
}
}
}
}
}
}
}
}
Tried it on xcode 12,5 with iOS 14 as target

SwiftUI - Form Picker - How to prevent navigating back on selected?

I'm implementing Form and Picker with SwiftUI. There is a problem that it automatically navigates back to Form screen when I select a Picker option, how to keep it stay in selection screen?
Code:
struct ContentView: View {
#State private var selectedStrength = "Mild"
let strengths = ["Mild", "Medium", "Mature"]
var body: some View {
NavigationView {
Form {
Section {
Picker("Strength", selection: $selectedStrength) {
ForEach(strengths, id: \.self) {
Text($0)
}
}
}
}
.navigationTitle("Select your cheese")
}
}
}
Actual:
Expect: (sample from Iphone Settings)
You may have to make a custom view that mimics what the picker looks like:
struct ContentView: View {
let strengths = ["Mild", "Medium", "Mature"]
#State private var selectedStrength = "Mild"
var body: some View {
NavigationView {
Form {
Section {
NavigationLink(destination: CheesePickerView(strengths: strengths, selectedStrength: $selectedStrength)) {
HStack {
Text("Strength")
Spacer()
Text(selectedStrength)
.foregroundColor(.gray)
}
}
}
}
.navigationTitle("Select your cheese")
}
}
}
struct CheesePickerView: View {
let strengths: [String]
#Binding var selectedStrength: String
var body: some View {
Form {
Section {
ForEach(0..<strengths.count){ index in
HStack {
Button(action: {
selectedStrength = strengths[index]
}) {
HStack{
Text(strengths[index])
.foregroundColor(.black)
Spacer()
if selectedStrength == strengths[index] {
Image(systemName: "checkmark")
.foregroundColor(.blue)
}
}
}.buttonStyle(BorderlessButtonStyle())
}
}
}
}
}
}

Button with NavigationLink and function call SwiftUI

I have an issue with NavigationLinks with conditions. It doesn't react what I'm expected. When a user click on the button the function "test" must be called and give a return value. If the return value is true the "SheetView" must be openend directly without clicking on the NavigationLink text. Please could someone give me a help on this one. Thanks in advance
I made a small (sample) program for showing the issue.
import SwiftUI
struct LoginView: View {
#State var check = false
#State var answer = false
var body: some View {
NavigationView {
VStack{
Text("it doesn't work")
Button(action: {
answer = test(value: 2)
if answer {
//if the return value is true then directly navigate to the sheetview
NavigationLink(
destination: SheetView(),
label: {
Text("Navigate")
})
}
}, label: {
Text("Calculate")
})
}
}
}
func test(value: Int) -> Bool {
if value == 1 {
check = false
} else {
print("Succes")
check = true
}
return check
}
}
struct SheetView: View {
var body: some View {
NavigationView {
VStack{
Text("Test")
.font(.title)
}
}
}
}
The answer from Yodagama works if you were trying to present a sheet (because you called your navigation destination SheetView), but if you were trying to navigate to SheetView instead of present a sheet, the following code would do that.
struct LoginView: View {
#State var check = false
#State var answer = false
var body: some View {
NavigationView {
VStack{
Text("it doesn't work")
NavigationLink(destination: SheetView(), isActive: $answer, label: {
Button(action: {
answer = test(value: 2)
}, label: {
Text("Calculate")
})
})
}
}
}
func test(value: Int) -> Bool {
if value == 1 {
check = false
} else {
print("Succes")
check = true
}
return check
}
}
struct SheetView: View {
var body: some View {
NavigationView {
VStack{
Text("Test")
.font(.title)
}
}
}
}
struct LoginView: View {
#State var check = false
#State var answer = false
var body: some View {
NavigationView {
VStack{
Text("it doesn't work")
Button(action: {
answer = test(value: 2)
//<= here
}, label: {
Text("Calculate")
})
}
.sheet(isPresented: $answer, content: { //<= here
SheetView()
})
}
}
...

SwiftUI Reorder list dynamic sections from another view

I have a simple List with sections that are stored inside an ObservableObject. I'd like to reorder them from another view.
This is my code:
class ViewModel: ObservableObject {
#Published var sections = ["S1", "S2", "S3", "S4"]
func move(from source: IndexSet, to destination: Int) {
sections.move(fromOffsets: source, toOffset: destination)
}
}
struct ContentView: View {
#ObservedObject var viewModel = ViewModel()
#State var showOrderingView = false
var body: some View {
VStack {
Button("Reorder sections") {
self.showOrderingView = true
}
list
}
.sheet(isPresented: $showOrderingView) {
OrderingView(viewModel: self.viewModel)
}
}
var list: some View {
List {
ForEach(viewModel.sections, id: \.self) { section in
Section(header: Text(section)) {
ForEach(0 ..< 3, id: \.self) { _ in
Text("Item")
}
}
}
}
}
}
struct OrderingView: View {
#ObservedObject var viewModel: ViewModel
var body: some View {
NavigationView {
List {
ForEach(viewModel.sections, id: \.self) { section in
Text(section)
}
.onMove(perform: viewModel.move)
}
.navigationBarItems(trailing: EditButton())
}
}
}
But in the OrderingView when trying to move sections I'm getting this error: "Attempt to create two animations for cell". Likely it's because the order of the sections has changed.
How can I change the order of the sections?
The problem of this scenario is recreated many times ViewModel, so modifications made in sheet just lost. (The strange thing is that in SwiftUI 2.0 with StateObject these changes also lost and EditButton does not work at all.)
Anyway. It looks like here is a found workaround. The idea is to break interview dependency (binding) and work with pure data passing them explicitly into sheet and return them back explicitly from it.
Tested & worked with Xcode 12 / iOS 14, but I tried to avoid using SwiftUI 2.0 features.
class ViewModel: ObservableObject {
#Published var sections = ["S1", "S2", "S3", "S4"]
func move(from source: IndexSet, to destination: Int) {
sections.move(fromOffsets: source, toOffset: destination)
}
}
struct ContentView: View {
#ObservedObject var viewModel = ViewModel()
#State var showOrderingView = false
var body: some View {
VStack {
Button("Reorder sections") {
self.showOrderingView = true
}
list
}
.sheet(isPresented: $showOrderingView) {
OrderingView(sections: viewModel.sections) {
self.viewModel.sections = $0
}
}
}
var list: some View {
List {
ForEach(viewModel.sections, id: \.self) { section in
Section(header: Text(section)) {
ForEach(0 ..< 3, id: \.self) { _ in
Text("Item")
}
}
}
}
}
}
struct OrderingView: View {
#State private var sections: [String]
let callback: ([String]) -> ()
init(sections: [String], callback: #escaping ([String]) -> ())
{
self._sections = State(initialValue: sections)
self.callback = callback
}
var body: some View {
NavigationView {
List {
ForEach(sections, id: \.self) { section in
Text(section)
}
.onMove {
self.sections.move(fromOffsets: $0, toOffset: $1)
}
}
.navigationBarItems(trailing: EditButton())
}
.onDisappear {
self.callback(self.sections)
}
}
}
A possible workaround solution for SwiftUI 1.0
I found a workaround to disable animations for the List by adding .id(UUID()):
var list: some View {
List {
...
}
.id(UUID())
}
This, however, messes the transition animations for NavigationLinks created with NavigationLink(destination:tag:selection:): Transition animation gone when presenting a NavigationLink in SwiftUI.
And all other animations (like onDelete) are missing as well.
The even more hacky solution is to disable list animations conditionally:
class ViewModel: ObservableObject {
...
#Published var isReorderingSections = false
...
}
struct OrderingView: View {
#ObservedObject var viewModel: ViewModel
var body: some View {
NavigationView {
...
}
.onAppear {
self.viewModel.isReorderingSections = true
}
.onDisappear {
self.viewModel.isReorderingSections = false
}
}
}
struct ContentView: View {
...
var list: some View {
List {
...
}
.id(viewModel.isReorderingSections ? UUID().hashValue : 1)
}
}

SwiftUI: Support multiple modals

I'm trying to setup a view that can display multiple modals depending on which button is tapped.
When I add just one sheet, everything works:
.sheet(isPresented: $showingModal1) { ... }
But when I add another sheet, only the last one works.
.sheet(isPresented: $showingModal1) { ... }
.sheet(isPresented: $showingModal2) { ... }
UPDATE
I tried to get this working, but I'm not sure how to declare the type for modal. I'm getting an error of Protocol 'View' can only be used as a generic constraint because it has Self or associated type requirements.
struct ContentView: View {
#State var modal: View?
var body: some View {
VStack {
Button(action: {
self.modal = ModalContentView1()
}) {
Text("Show Modal 1")
}
Button(action: {
self.modal = ModalContentView2()
}) {
Text("Show Modal 2")
}
}.sheet(item: self.$modal, content: { modal in
return modal
})
}
}
struct ModalContentView1: View {
var body: some View {
Text("Modal 1")
}
}
struct ModalContentView2: View {
var body: some View {
Text("Modal 2")
}
}
This works:
.background(EmptyView().sheet(isPresented: $showingModal1) { ... }
.background(EmptyView().sheet(isPresented: $showingModal2) { ... }))
Notice how these are nested backgrounds. Not two backgrounds one after the other.
Thanks to DevAndArtist for finding this.
Maybe I missed the point, but you can achieve it either with a single call to .sheet(), or multiple calls.:
Multiple .sheet() approach:
import SwiftUI
struct MultipleSheets: View {
#State private var sheet1 = false
#State private var sheet2 = false
#State private var sheet3 = false
var body: some View {
VStack {
Button(action: {
self.sheet1 = true
}, label: { Text("Show Modal #1") })
.sheet(isPresented: $sheet1, content: { Sheet1() })
Button(action: {
self.sheet2 = true
}, label: { Text("Show Modal #2") })
.sheet(isPresented: $sheet2, content: { Sheet2() })
Button(action: {
self.sheet3 = true
}, label: { Text("Show Modal #3") })
.sheet(isPresented: $sheet3, content: { Sheet3() })
}
}
}
struct Sheet1: View {
var body: some View {
Text("This is Sheet #1")
}
}
struct Sheet2: View {
var body: some View {
Text("This is Sheet #2")
}
}
struct Sheet3: View {
var body: some View {
Text("This is Sheet #3")
}
}
Single .sheet() approach:
struct MultipleSheets: View {
#State private var showModal = false
#State private var modalSelection = 1
var body: some View {
VStack {
Button(action: {
self.modalSelection = 1
self.showModal = true
}, label: { Text("Show Modal #1") })
Button(action: {
self.modalSelection = 2
self.showModal = true
}, label: { Text("Show Modal #2") })
Button(action: {
self.modalSelection = 3
self.showModal = true
}, label: { Text("Show Modal #3") })
}
.sheet(isPresented: $showModal, content: {
if self.modalSelection == 1 {
Sheet1()
}
if self.modalSelection == 2 {
Sheet2()
}
if self.modalSelection == 3 {
Sheet3()
}
})
}
}
struct Sheet1: View {
var body: some View {
Text("This is Sheet #1")
}
}
struct Sheet2: View {
var body: some View {
Text("This is Sheet #2")
}
}
struct Sheet3: View {
var body: some View {
Text("This is Sheet #3")
}
}
I'm not sure whether this was always possible, but in Xcode 11.3.1 there is an overload of .sheet() for exactly this use case (https://developer.apple.com/documentation/swiftui/view/3352792-sheet). You can call it with an Identifiable item instead of a bool:
struct ModalA: View {
var body: some View {
Text("Hello, World! (A)")
}
}
struct ModalB: View {
var body: some View {
Text("Hello, World! (B)")
}
}
struct MyContentView: View {
enum Sheet: Hashable, Identifiable {
case a
case b
var id: Int {
return self.hashValue
}
}
#State var activeSheet: Sheet? = nil
var body: some View {
VStack(spacing: 42) {
Button(action: {
self.activeSheet = .a
}) {
Text("Hello, World! (A)")
}
Button(action: {
self.activeSheet = .b
}) {
Text("Hello, World! (B)")
}
}
.sheet(item: $activeSheet) { item in
if item == .a {
ModalA()
} else if item == .b {
ModalB()
}
}
}
}
I personally would mimic some NavigationLink API. Then you can create a hashable enum and decide which modal sheet you want to present.
extension View {
func sheet<Content, Tag>(
tag: Tag,
selection: Binding<Tag?>,
content: #escaping () -> Content
) -> some View where Content: View, Tag: Hashable {
let binding = Binding(
get: {
selection.wrappedValue == tag
},
set: { isPresented in
if isPresented {
selection.wrappedValue = tag
} else {
selection.wrappedValue = .none
}
}
)
return background(EmptyView().sheet(isPresented: binding, content: content))
}
}
enum ActiveSheet: Hashable {
case first
case second
}
struct First: View {
var body: some View {
Text("frist")
}
}
struct Second: View {
var body: some View {
Text("second")
}
}
struct TestView: View {
#State
private var _activeSheet: ActiveSheet?
var body: some View {
print(_activeSheet as Any)
return VStack
{
Button("first") {
self._activeSheet = .first
}
Button("second") {
self._activeSheet = .second
}
}
.sheet(tag: .first, selection: $_activeSheet) {
First()
}
.sheet(tag: .second, selection: $_activeSheet) {
Second()
}
}
}
I wrote a library off plivesey's answer that greatly simplifies the syntax:
.multiSheet {
$0.sheet(isPresented: $sheetAPresented) { Text("Sheet A") }
$0.sheet(isPresented: $sheetBPresented) { Text("Sheet B") }
$0.sheet(isPresented: $sheetCPresented) { Text("Sheet C") }
}
I solved this by creating an observable SheetContext that holds and manages the state. I then only need a single context instance and can tell it to present any view as a sheet. I prefer this to the "active view" binding approach, since you can use this context in multiple ways.
I describe it in more details in this blog post: https://danielsaidi.com/blog/2020/06/06/swiftui-sheets
I think i found THE solution. It's complicated so here is the teaser how to use it:
Button(action: {
showModal.wrappedValue = ShowModal {
AnyView( TheViewYouWantToPresent() )
}
})
Now you can define at the button level what you want to present. And the presenting view does not need to know anything. So you call this on the presenting view.
.background(EmptyView().show($showModal))
We call it on the background so the main view does not need to get updated, when $showModal changes.
Ok so what do we need to get this to work?
1: The ShowModal class:
public enum ModalType{
case sheet, fullscreen
}
public struct ShowModal: Identifiable {
public let id = ""
public let modalType: ModalType
public let content: () -> AnyView
public init (modalType: ModalType = .sheet, #ViewBuilder content: #escaping () -> AnyView){
self.modalType = modalType
self.content = content
}
}
Ignore id we just need it for Identifiable. With modalType we can present the view as sheet or fullscreen. And content is the passed view, that will be shown in the modal.
2: A ShowModal binding which stores the information for presenting views:
#State var showModal: ShowModal? = nil
And we need to add it to the environment of the view thats responsible for presentation. So we have easy access to it down the viewstack:
VStack{
InnerViewsThatWantToPresentModalViews()
}
.environment(\.showModal, $showModal)
.background(EmptyView().show($showModal))
In the last line we call .show(). Which is responsible for presentation.
Keep in mind that you have to create #State var showModal and add it to the environment again in a view thats shown modal and wants to present another modal.
4: To use .show we need to extend view:
public extension View {
func show(_ modal: Binding<ShowModal?>) -> some View {
modifier(VM_Show(modal))
}
}
And add a viewModifier that handles the information passed in $showModal
public struct VM_Show: ViewModifier {
var modal: Binding<ShowModal?>
public init(_ modal: Binding<ShowModal?>) {
self.modal = modal
}
public func body(content: Content) -> some View {
guard let modalType = modal.wrappedValue?.modalType else{ return AnyView(content) }
switch modalType {
case .sheet:
return AnyView(
content.sheet(item: modal){ modal in
modal.content()
}
)
case .fullscreen:
return AnyView(
content.fullScreenCover(item: modal) { modal in
modal.content()
}
)
}
}
}
4: Last we need to set showModal in views that want to present a modal:
Get the variable with: #Environment(\.showModal) var showModal. And set it like this:
Button(action: {
showModal.wrappedValue = ShowModal(modalType: .fullscreen) {
AnyView( TheViewYouWantToPresent() )
}
})
In the view that defined $showModal you set it without wrappedValue: $showModal = ShowModal{...}
As an alternative, simply putting a clear pixel somewhere in your layout might work for you:
Color.clear.frame(width: 1, height: 1, alignment: .center).sheet(isPresented: $showMySheet, content: {
MySheetView();
})
Add as many pixels as necessary.