Reorder SwiftUI List in Mac App with LazyVStack - swiftui

Here is a simple macOS demo app that compares using a SwiftUI List and a LazyVStack. I prefer to use a LazyVStack because it's easier to customize the style. But it seems some of the built-in functionality is missing, such as reordering list items (as shown below)
import SwiftUI
class MyData: ObservableObject{
#Published var items = ["One", "Two", "Three", "Four", "Five"]
}
struct ContentView: View {
#StateObject var model = MyData()
var body: some View {
HStack{
//--- List ---
VStack{
Text("List")
.fontWeight(.bold)
List{
ForEach(model.items, id: \.self){ item in
Text(item)
}
.onMove(perform: move)
}
}
//--- LazyVStack ---
VStack{
Text("LazyVStack")
.fontWeight(.bold)
ScrollView {
LazyVStack {
ForEach(model.items, id: \.self){ item in
Text(item)
}
.onMove(perform: move)
}
}
}
}
}
//Reorder List
func move(from source: IndexSet, to destination: Int) {
model.items.move(fromOffsets: source, toOffset: destination )
}
}
The reordering of items works fine in the List example. But nothing happens in the LazyVStack.
Is there a way to get the .onMove functionality to work in the LazyVStack instance? Or do I have to implement a full bevy of custom .onDrag stuff with NSItemProvider?

Related

SwiftUI bug on NavigationLink when showing items as GridItem in List

Ok, I'm pretty sure this is a bug on Apple's part.
I fetch data using #SectionedFetchRequest.
I want to show links to detail in grids divided by sections (a bit like iOS Photos, where individual photos show as rectangles separated by a certain period, e.g. November 2021.
However, NavigationLink always opens the last item in a given grid, even if I tap some other item in this grid.
The important part: this issue does not occur when using ScrollView. It only occurs when using List.
A minimal example is below. Any fixes/workarounds will be much appreciated!
import SwiftUI
struct ItemsListView: View {
#EnvironmentObject var viewRouter: ViewRouter
#SectionedFetchRequest(
sectionIdentifier: SortModel.default.section,
sortDescriptors: SortModel.default.descriptors,
animation: .default
)
private var coreData: SectionedFetchResults<String, Item>
let layout = [GridItem(.adaptive(minimum: 100)),
GridItem(.adaptive(minimum: 100)),
GridItem(.adaptive(minimum: 100))]
var body: some View {
List { // **Bug disappears when List replaced with Scrollview**
ForEach(coreData) { section in
Section(header: Text(section.id)) {
LazyVGrid(columns: layout, spacing: 10) {
ForEach(section) { item in
Button(action: {
viewRouter.selectedItem = item
viewRouter.detailActive = true
}, label: {
LabelView(item: item)
})
} //: foreach
} //: LazyVGrid
} //: section
} //: ForEach section
} //: list
VStack(spacing: 0) {
NavigationLink(destination: ItemDetailView(item: viewRouter.selectedItem), isActive: $viewRouter.detailActive){ EmptyView() }
}
.hidden()
} //: body
} //: struct
struct LabelView: View {
let item: Item
var body: some View {
Image("\(item.image)") // some image
.resizable()
.scaledToFill()
.clipped()
.cornerRadius(12)
} //: body
} //: struct
struct ItemDetailView: View {
let item: Item
var body: some View {
VStack {
Text("This is the detail view for \(item.name)"
} //: vstack
} //: body
} //: struct

SwiftUI ToolbarItem doesn't present a View from a NavigationLink

I don't know if this is a bug or I am doing something wrong here. I've added a new button on the Navigation bar that would present a new view.
struct MyView: View {
#ObservedObject var viewModel = MyViewModel()
var body: some View {
List(viewModel.data, id: \.name) { data in
NavigationLink(destination: MyDetailView(data: data.name)) {
Text(data.name)
}
}
.listStyle(InsetGroupedListStyle())
.edgesIgnoringSafeArea(.all)
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
NavigationLink(destination: MyDetailView()) {
Text("New Element")
}
}
}
}
}
This is being tested on the newest iOS 14 beta (beta 6) and Xcode 12 (beta 6). As far as I know a Navigation Link presents fine the new view when on a List but in the toolbar as shown that's not the case. The button on the toolbar it's visible and active but doesn't trigger showing the new view.
I found using an HStack with an empty text as the first element also works, it lets the navigationLink act correctly.
.toolbar {
ToolbarItem(placement: .navigationBarLeading) {
HStack {
Text("")
NavigationLink(destination: SettingsView()) {
Image(systemName: "gear")
.font(.title)
}
}
}
NavigationLink should be inside NavigationView. Toolbar is not in NavigationView, put buttons in it.
So assuming you have somewhere in parent
NavigationView {
MyView()
}
here is a solution:
struct MyView: View {
#ObservedObject var viewModel = MyViewModel()
#State private var showNew = false
var body: some View {
List(viewModel.data, id: \.name) { data in
NavigationLink(destination: MyDetailView(data: data.name)) {
Text(data.name)
}
}
.listStyle(InsetGroupedListStyle())
.background(
NavigationLink(destination: MyDetailView(), isActive: $showNew) {
EmptyView()
}
)
.edgesIgnoringSafeArea(.all)
.toolbar {
ToolbarItem(placement: .navigationBarTrailing) {
Button("New Element") {
self.showNew = true
}
}
}
}
}
Using Asperi solution may not work if your navigation link directs to a view with keyboard input.
After navigation link, toolbar in the new view loaded correctly but when providing input with keyboard and dismissing keyboard all toolbar items disappears.
The solution is to place NavigationLink not in View but in navigationBarItems, example:
.navigationBarItems(
leading:
NavigationLink(
destination: Creator(),
isActive: $showCreator,
label: {
Text("")
}))

SwiftUI EditButton in HStack not activating edit mode

As part of a bigger Form I'd like to have a Section with a List whose entries can be reordered.
In the whole view it should be only possible to edit that particular list, nothing else. Therefore I'd like to have the EditButton near the List.
If I just set the EditButton as the Section header, reordering List items works but I can't display a section title:
struct ContentView: View {
private let items = Range(1...4).map { "Item " + String($0) }
var body: some View {
Form {
Section(header: EditButton()) {
ForEach(items, id: \.self) { item in
Text(item)
}
.onMove(perform: reorderItems)
.onDelete(perform: deleteItems)
}
}
}
func reorderItems(from sourceIndices: IndexSet, to destinationIndex: Int) { /* ... */ }
func deleteItems(at offsets: IndexSet) { /* ... */ }
}
But if I wrap the EditButton in a HStack to display the button on the right, a tap on "Edit" changes the button's title to "Done" but doesn't start List's edit mode anymore:
struct ContentView: View {
#Environment(\.editMode) var editMode
private let items = Range(1...4).map { "Item " + String($0) }
var body: some View {
Form {
Section(header: HStack {
Text("Section title")
Spacer()
EditButton()
}.environment(\.editMode, self.editMode)) {
ForEach(items, id: \.self) { item in
Text(item)
}
.onMove(perform: reorderItems)
.onDelete(perform: deleteItems)
}
}
}
func reorderItems(from sourceIndices: IndexSet, to destinationIndex: Int) { /* ... */ }
func deleteItems(at offsets: IndexSet) { /* ... */ }
}
I also tried, as the code shows, passing the editMode environment variable to the HStack, but nothing helped.
Is there any way to get the EditButton inside an HStack working?
(Remark: As the List is part of a bigger Form, placing the EditButton out of the Section as suggested here is not an option in my case.)
Here is working solution - looks like they require that EditButton was a root view of section, so we can construct everything else above it. (tested with Xcode 11.4 / iOS 13.4)
Note: #Environment(\.editMode) var editMode is not needed
Section(header:
EditButton().frame(maxWidth: .infinity, alignment: .trailing)
.overlay(Text("Header"), alignment: .leading)
)
{
ForEach(items, id: \.self) { item in
Text(item)
}
.onMove(perform: reorderItems)
.onDelete(perform: deleteItems)
}

SwiftUI Reload View

I have a struct which shuffles and Lists records from CoreData.
I would like to reload / Refresh the List view with a Button.
I tried to use a function from within the Button.
Is there a way I can do this?
var body: some View {
VStack {
List {
ForEach(dictionary.shuffled().prefix(upTo: 10),id: \.self) { word in
HStack {
Text("\(word.englishWord)")
.foregroundColor(Color.blue)
Text("| \(word.urhoboWord) |")
.foregroundColor(Color.green)
Image(word.imageName)
.resizable()
.frame(width:40, height: 40)
}//HStack
}//End of ForEach
}//End of List
//Button to reload and shuffle list
Button(action: {}) {
Text("Shuffle")
.padding()
.background(Color.black)
.foregroundColor(Color.white)
.cornerRadius(6)
}
.navigationBarTitle(Text("Begin Learning"),displayMode: .inline)
Just trigger any value of the #State or #Published of #ObservableObject.
If you do not have such, just create one:
#State var refresh: Bool = false
func update() {
refresh.toggle()
}
You should move this dictionary.shuffled().prefix(upTo: 10) to your ViewModel and your view just reload base on the data.
Take a look at this code for reference:
struct SampleShuffleView : View {
#ObservedObject var viewModel : ShuffleViewModel = ShuffleViewModel()
var body : some View {
VStack {
List(self.viewModel.listData, id: \.self) { str in
Text(str)
}
Button(action: self.shuffle) {
Text("Shuffle me").padding()
}.background(Color.white).padding()
}
}
func shuffle() {
self.viewModel.shuffle()
}
}
class ShuffleViewModel : ObservableObject {
#Published var listData = ["one", "two", "three", "four"]
func shuffle() {
listData.shuffle()
//or listData = dictionary.shuffled().prefix(upTo: 10)
}
}
Note: All view's components will be reloaded when #ObservedObject changes, so consider to separate smaller view-viewmodel(s), or using #State variable.
Hope this helps.
Think about. To show array and shuffle on tap, do exactly what you would like to see. first show us the array in some "list" like manner and next shuffle it on user action.
struct ContentView: View {
#State var arr = ["ALFA", "BETA", "GAMA", "DELTA"]
var body: some View {
VStack {
VStack {
Divider()
ForEach(arr, id: \.self) { element in
VStack {
Text(element)
Divider()
}
}
}
Spacer()
Button(action: {
self.arr.shuffle()
}) {
Text("Shuffle")
}
Spacer()
}
}
}
arr.shuffle() changed the #State of View and force SwiftUI to "reload it" automatically.

SwiftUI NavigationButton without the disclosure indicator?

When making a List with a row that pushes to a new view, SwiftUI adds a disclosure indicator ">" automatically? How do I remove it if I don't want it?
NavigationView {
List {
NavigationButton(destination: DetailView()) {
ListItem()
}
}
.navigationBarTitle(Text("Some title"))
}
On a UITableViewCell you set Accessory to None but how do I do that in SwiftUI?
Setting the NavigationLink width and hiding it did the trick for me
List {
ForEach(pages) { page in
HStack(spacing: 0) {
Text("Something")
NavigationLink(destination: Text("Somewhere")) {
EmptyView()
}
.frame(width: 0)
.opacity(0)
}
}
}
Swift 5, Xcode 11. ZStack works perfect.
var body: some View {
NavigationView {
List {
ForEach(viewModel.currenciesViewModel) { cellViewModel in
ZStack {
cellViewModel.makeView()
NavigationLink(destination: ChooseCurrencyListView()) {
EmptyView()
}
.buttonStyle(PlainButtonStyle())
}
}
}
.navigationBarHidden(true)
.navigationBarTitle("", displayMode: .inline)
}
}
The easiest one. The content for each item in the list.
ZStack {
NavigationLink(destination: DetailView()) {
EmptyView()
}.hidden()
RowView()
}
As workaround I can suggest to add .padding modifier like this:
NavigationView {
List {
NavigationButton(destination: DetailView()) {
ListItem()
}
}
.navigationBarTitle(Text("Some title"))
}
.padding(.trailing, -32.0)
So you will get rows without visible disclosure:
You can also put it in the .background modifier:
List {
Text("Go to...")
.background(NavigationLink("", destination: Text("Detail View")))
}
If you already have the background modifier on the Text, you can wrap the Text in a HStack and apply background to the HStack.
What you can do, if you are using list, is setting the navigationlink to hidden and its frame width to zero.
HStack{
Button(action: {self.statusShow = 1}, label: {
Image(systemName: "info.circle")
})
NavigationLink(destination: StimulatorSettingView(),
tag: 1,
selection: self.$statusShow){
EmptyView()
}.hidden().frame(width: 0)
}
This worked for me.
As of beta 6, this works well:
struct SwiftUIView: View {
var body: some View {
NavigationView {
List {
HStack {
Text("My Cell Content")
NavigationLink(destination: Text("destination"), label: {
EmptyView()
})
}
}
}
}
}
You don't have to use NavigationLink to wrap your Label directly. It will work as long as the link is anywhere in your view hierarchy.
Here I've wrapped it in a button, which allows you to trigger an action prior to pushing the view. Since the NavigationLink has an EmptyView for the label the disclosure indicator is not visible. You can also style this with ButtonStyle.
struct NavigationButton<Destination: View, Label: View>: View {
var action: () -> Void = { }
var destination: () -> Destination
var label: () -> Label
#State private var isActive: Bool = false
var body: some View {
Button(action: {
self.action()
self.isActive.toggle()
}) {
self.label()
.background(NavigationLink(destination: self.destination(), isActive: self.$isActive) {
EmptyView()
})
}
}
}
And to use it:
NavigationButton(
action: { print("tapped!") },
destination: { Text("Pushed View") },
label: { Text("Tap me") }
)
NavigationLink is what we should define in a scope enclosed inside a NavigationView.
But when we use NavigationLink it is attached to the enclosing view, so to reuse the same NavigationLink with other views, we use tag which differentiates between different Destinations.
struct SwiftUIView: View {
#State private var viewState: Int? = 0
var body: some View {
NavigationView {
VStack {
NavigationLink(destination: Text("View 1"), tag: 1, selection: $viewState) {
EmptyView()
}
NavigationLink(destination: Text("View 2"), tag: 2, selection: $viewState) {
EmptyView()
}
Text("First View")
.onTapGesture {
self.viewState = 1
}
Text("Second View")
.onTapGesture {
self.viewState = 2
}
}
}
}
}
Here we bind a Hashable property with all the NavigationLinks present in our VStack so that when a particular View is tapped we can notify which Destination should be opened by setting the value of Bindable property.
If we don't notify the correct Destination by setting the value of tag, always the View defined inside the Closure of NavigationLink will be clickable and nothing else.
Using this approach you don't need to wrap all your clickable views inside NavigationView, any action on any view can use any NavigationLink just by setting the tag.
Thanks, hope this helps.
Works well for me!
import SwiftUI
struct LandmarkList: View {
var body: some View {
NavigationView {
List(landmarkData) { landmark in
LandmarkRow(landmark: landmark)
NavigationLink(destination: LandmarkDetail(landmark: landmark)) {
EmptyView()
}
}
.navigationBarTitle(Text("Landmarks"))
}
}
}
struct LandmarkList_Previews: PreviewProvider {
static var previews: some View {
ForEach(["iPhone SE", "iPhone 11 Pro Max"], id: \.self) { deviceName in
LandmarkList()
.previewDevice(PreviewDevice(rawValue: deviceName))
.previewDisplayName(deviceName)
}
}
}
Use .frame(width: 0).opacity(0.0):
NavigationView {
List {
ForEach(options) {
option in
ZStack {
YourView(option: option)
NavigationLink(destination: ProductListView(),
label: {
EmptyView()
}).frame(width: 0).opacity(0.0)
}.listRowInsets(EdgeInsets())
}
}.navigationBarHidden(true)
}
My version of this solution is to make a view modifier. I think it's the cleanest way, as it doesn't use AnyView.
Note that this solution runs the init() for the destination when it draws the element the .navigationLink() is attached to.
Usage
Text("Link")
.navigationLink({
// put your destination here
})
How To
import SwiftUI
extension View {
func navigationLink<Destination: View>(_ destination: #escaping () -> Destination) -> some View {
modifier(NavigationLinkModifier(destination: destination))
}
}
fileprivate struct NavigationLinkModifier<Destination: View>: ViewModifier {
#ViewBuilder var destination: () -> Destination
func body(content: Content) -> some View {
content
.background(
NavigationLink(destination: self.destination) { EmptyView() }.opacity(0)
)
}
}
This helps to push and pass the model to the next navigation view controller.
struct ContentView : View {
#State var model = PostListViewModel()
var body: some View {
NavigationView {
List(model.post) { post in
ListCell(listData: post)
}.navigationBarTitle(Text("My Post"))
}
}
}
struct ListCell: View {
var listData: Post
var body: some View {
return NavigationButton(destination: DetailContentView(post: listData)) {
HStack {
ImageRow(model: listData) // Get image
VStack(alignment: .leading) {
Text(listData.login).font(.headline).lineLimit(nil)
Text(listData.url).font(.subheadline).lineLimit(nil)
}.padding(.leading, 10)
}.padding(.init(top: 5, leading: 0, bottom: 5, trailing: 0))
}
}
}
Here's a reusable "plain" navigation link view (i.e. without the chevron disclosure indicator) that can be a drop-in replacement for NavigationLink:
struct PlainNavigationLink<Label, Destination>: View where Label: View, Destination: View {
#ViewBuilder var destination: () -> Destination
#ViewBuilder var label: () -> Label
var body: some View {
label()
.background(
NavigationLink(destination: destination, label: {})
.opacity(0)
)
}
}
To use it, simply replace NavigationLink with PlainNavigationLink:
NavigationView { // or NavigationStack in iOS 16
List {
ForEach(1...30, id: \.self) { _ in
PlainNavigationLink {
Text("Hello, world!")
} label: {
Text("Hello, world!")
}
}
}
}
We can also extend it with convenience initializers for LocalizedStringKey and String, just like NavigationLink does.
just came here looking for the answer to this question, but none of the proposed solutions worked for me (can't have an empty view, because i want to put something in the list row; i'm already messing with the padding (and increasing trailing padding didn't seem to work) ... i was about to give up, and then something occurred to me: what if you crank up the z-index of the list row itself? seemed somewhat unlikely, but i gave it a try and, i'll be damned, it worked! i was so pleasantly surprised, i felt like sharing ...
e.g.:
// in body of your list row view
HStack(alignment: .top, spacing: 0.0) {
// stuff ...
}
.zIndex(9999999999)
If you need children behaviour for List and NavigationLink, without additional discloser in the same time, I want to promote this tricky solution, main point at HStack
var body: some View {
NavigationView {
List(items, children: \.items) { item in
ZStack {
NavigationLink(destination: DetailsView()) {
EmptyView()
}.hidden()
HStack {
RowView(item: item)
Spacer()
}
}
}
}
}
Once you put your button in a scrollview, the disclosure button will be hidden. Just make sure to disable your scroll indicator.
there is no documentation yet, so you can use ScrollView for now
NavigationView {
ScrollView {
ForEach(0...100){ x in
NavigationButton(destination: Text("ss")) {
HStack {
Text(String(x))
Spacer()
}
.padding()
.background(Color.white)
.shadow(radius:1,y:1)
}
}
.frame(width: UIScreen.main.bounds.width - 32)
.padding()
}
}
Removing List and just using ForEach works fine with navigation link. You just have to create your own list row. This works for me
NavigationView {
ForEach(pages) {
page in
NavigationLink(destination: DetailView()) {
ListItem()
}
}
}