Use of unresolved identifier 'PresentationButton', is there any new Class introduced for 'PresentationButton'?
Did anyone have used the 'PresentationButton' in their code. I would like to open an view on click of the image or content frame.
PresentationButton(destination: ContentView()) {
CourseView()
}
I did tried to find out the documentation in apple developer's website but I do not see any.
PresentationButton is deprecated. If you want to present a sheet use something like below.
struct ModalExample: View {
#State var show = false
var detail: ModalView {
return ModalView()
}
var body: some View {
VStack {
Button("Present") {
self.show = true
}
}
.sheet(isPresented: $show, content: { ModalView() })
}
}
struct ModalView : View {
#Environment(\.presentationMode) var presentationMode
var body: some View {
VStack {
Text("Modal")
Button("Close") {
self.presentationMode.value.dismiss()
}
}
}
}
If you're not showing the view modally (in which case .sheet is the way to go), the preferred way in Xcode 11 beta 5 is using NavigationLink.
NavigationLink(destination: ContentView()) {
Text("show ContentView")
}
Related
I have a macOS app with two columns. The left column is a list that presents the filename and date of the unit (file) that I'm working on. The second column, to the right, should present the content of each file when selected.
I have an array that contains that information and I create a list for the left column that presents each item. I added a detail: with a TextEditor that allows the user to see the data and modify it if necessary. I have been trying to set the #State var text to the contents of currentunit.text but I don't know how to pass that the detail:. If I try to assign it (as in text = x) then I get an error saying that it doesn't conform to View.
I tried then to maybe load it by getting the index of the current selected unit, using the selectedUnitId, and using something like this to get the index:
func getIndex(uuid: UUID) -> Int? {
return data.units.firstIndex(where: {$0.id == uuid})
}
But I get nowhere with a collection of different errors.
Regardless, how do I pass data to the detail: part of the code? I have looked into many examples of NavigationSplitView and they are all very similar, just showing the basic usage and that's it.
Thanks!
Code:
struct Unit: Codable, Hashable, Identifiable {
let id: UUID
var text: String
var date = Date()
var dateText: String {
let df = DateFormatter()
df.dateFormat = "EEEE, MMM d yyyy, h:mm a"
return df.string(from: date)
}
var changed: Bool = false
}
final class UnitModel: ObservableObject {
#AppStorage("unit") public var units: [Unit] = []
init() {
self.units = self.units.sorted(by: {
$0.date.compare($1.date) == .orderedDescending
})
}
func sortList() {
self.units = self.units.sorted(by: {
$0.date.compare($1.date) == .orderedDescending
})
}
}
struct ContentView: View {
#EnvironmentObject private var data: UnitModel
#State var selectedUnitId: UUID?
#State var text: String = ""
var body: some View {
NavigationSplitView {
List(data.units, selection: $selectedUnitId) { currentunit in
VStack(alignment: .leading) {
Text(currentunit.filename)
Text(currentunit.dateText)
}
}
} detail: {
// here: how do I preload $text with the text from the unit?
VStack(alignment: .leading) {
TextEditor(text: $text)
}
}
}
}
I also tried:
struct ContentView: View {
#EnvironmentObject private var data: UnitModel
#State var selectedNoteId: UUID?
var body: some View {
NavigationSplitView {
List(data.units, selection: $selectedNoteId) { currentunit in
NavigationLink{
UnitView(unit: currentunit, text: currentunit.text)
} label: {
VStack(alignment: .leading) {
Text(currentunit.filename)
Text(currentunit.dateText)
}
}
}
} detail: {
Text("Select a unit.")
}
}
}
struct UnitView: View {
#EnvironmentObject private var data: UnitModel
var unit: Unit
#State var text: String
var body: some View {
VStack(alignment: .leading) {
TextEditor(text: $text)
}
}
}
But again, I don't know how to initialize the text variable with the text of the current unit. I only get the initial one selected, and even tho I can see a new unit selected, the text remains the same and doesn't update.
UPDATED if I change the code to use NavigationView then it works as it should, so what's going with the new way that Apple is make us use now? Namely NavigationSplitView and NavigationStack?
Here's the code that work as it should but it's deprecated according to Apple:
NavigationView {
List(data.units, selection: $selectedNoteId) { currentunit in
NavigationLink(
destination: UnitView(unit: currentunit, text: currentunit.text),
label: {
VStack(alignment: .leading) {
Text(currentunit.filename)
Text(currentunit.dateText)
}
}
)
}
Apple's Defining the source of truth using a custom binding
tutorial covers this. Your code would look something like this:
} detail: {
DetailView(unitID: selectedUnitID) // not sure why they used binding
}
struct DetailView: View {
let unitID: Unit.ID
#EnvironmentObject private var store: UnitModel
private var unitBinding: Binding<Unit> {
Binding {
if let id = unitID {
return store.unit(with: id) ?? Unit.emptyUnit()
} else {
return Unit.emptyUnit()
}
} set: { updatedUnit in
store.update(updatedUnit)
}
}
var body: some View {
if store.contains(unitID) {
VStack(alignment: .leading) {
TextEditor(text: unitBinding.text)
}
}
else {
Text("Select Unit")
}
}
}
Note there currently (as of Xcode 14.2) is a known bug with the text cursor when using a TextField in the detail pane. Check by entering text, move cursor to middle and try to enter a character. The bug is the cursor jumps to the end.
In a multiplatform app I'm showing a sheet to collect a small amount of user input. On iOS, when the sheet is dismissed, the relevant .onDismiss method is called but not on macOS.
I've read that having the .onDismiss in the List can cause problems so I've attached it to the button itself with no improvement. I've also tried passing the isPresented binding through and toggling that within the sheet itself to dismiss, but again with no success.
I am employing a NavigationView but removing that makes no difference. The following simplified example demonstrates my problem. Any ideas? Should I even be using a sheet for this purpose on macOS?
I just want to make clear that I have no problem closing the sheet. The other questions I found were regarding problems closing the sheet - I can do that fine.
import SwiftUI
#main
struct SheetTestApp: App {
var body: some Scene {
WindowGroup {
ContentView()
}
}
}
struct ContentView: View {
var body: some View {
NavigationView {
ListView()
}
}
}
The List view.
struct ListView: View {
#State private var isPresented: Bool = false
var body: some View {
VStack {
Text("Patterns").font(.title)
Button(action: {
isPresented = true
}, label: {
Text("Add")
})
.sheet(isPresented: $isPresented, onDismiss: {
doSomethingAfter()
}) {
TestSheetView()
}
List {
Text("Bingo")
Text("Bongo")
Text("Banjo")
}
.onAppear(perform: {
doSomethingBefore()
})
}
}
func doSomethingBefore() {
print("Johnny")
}
func doSomethingAfter() {
print("Cash")
}
}
This is the sheet view.
struct TestSheetView: View {
#Environment(\.presentationMode) var presentationMode
#State private var name = ""
var body: some View {
Form {
TextField("Enter name", text: $name)
.padding()
HStack {
Spacer()
Button("Save") {
presentationMode.wrappedValue.dismiss()
}
Spacer()
}
}
.frame(minWidth: 300, minHeight: 300)
.navigationTitle("Jedward")
}
}
Bad issue.. you are right. OnDismiss is not called. Here is a workaround with Proxybinding
var body: some View {
VStack {
Text("Patterns").font(.title)
Button(action: {
isPresented = true
}, label: {
Text("Add")
})
List {
Text("Bingo")
Text("Bongo")
Text("Banjo")
}
.onAppear(perform: {
doSomethingBefore()
})
}
.sheet(isPresented: Binding<Bool>(
get: {
isPresented
}, set: {
isPresented = $0
if !$0 {
doSomethingAfter()
}
})) {
TestSheetView()
}
}
In this simple example app, I have the following requirements:
have multiple windows, each having it's own ViewModel
toggling the Toggle in one window should not update the other window's
I want to also be able to toggle via menu
As it is right now, the first two points are not given, the last point works though. I do already know that when I move the ViewModel's single source of truth to the ContentView works for the first two points, but then I wouldn't have access at the WindowGroup level, where I inject the commands.
import SwiftUI
#main
struct ViewModelAndCommandsApp: App {
var body: some Scene {
ContentScene()
}
}
class ViewModel: ObservableObject {
#Published var toggleState = true
}
struct ContentScene: Scene {
#StateObject private var vm = ViewModel()// injecting here fulfills the last point only…
var body: some Scene {
WindowGroup {
ContentView()
.environmentObject(vm)
.frame(width: 200, height: 200)
}
.commands {
ContentCommands(vm: vm)
}
}
}
struct ContentCommands: Commands {
#ObservedObject var vm: ViewModel
var body: some Commands {
CommandGroup(before: .toolbar) {
Button("Toggle Some State") {
vm.toggleState.toggle()
}
}
}
}
struct ContentView: View {
#EnvironmentObject var vm: ViewModel//injecting here will result in window independant ViewModels, but make them unavailable in `ContactScene` and `ContentCommands`…
var body: some View {
Toggle(isOn: $vm.toggleState, label: {
Text("Some State")
})
}
}
How can I fulfill theses requirements–is there a SwiftUI solution to this or will I have to implement a SceneDelegate (is this the solution anyway?)?
Edit:
To be more specific: I'd like to know how I can go about instantiating a ViewModel for each individual scene and also be able to know from the menu bar which ViewModel is meant to be changed.
Long story short, see the code below. The project is called WindowSample this needs to match your app name in the URL registration.
import SwiftUI
#main
struct WindowSampleApp: App {
var body: some Scene {
ContentScene()
}
}
//This can be done several different ways. You just
//need somewhere to store multiple copies of the VM
class AStoragePlace {
private static var viewModels: [ViewModel] = []
static func getAViewModel(id: String?) -> ViewModel? {
var result: ViewModel? = nil
if id != nil{
result = viewModels.filter({$0.id == id}).first
if result == nil{
let newVm = ViewModel(id: id!)
viewModels.append(newVm)
result = newVm
}
}
return result
}
}
struct ContentCommands: Commands {
#ObservedObject var vm: ViewModel
var body: some Commands {
CommandGroup(before: .toolbar) {
Button("Toggle Some State \(vm.id)") {
vm.testMenu()
}
}
}
}
class ViewModel: ObservableObject, Identifiable {
let id: String
#Published var toggleState = true
init(id: String) {
self.id = id
}
func testMenu() {
toggleState.toggle()
}
}
struct ContentScene: Scene {
var body: some Scene {
//Trying to init from 1 windowGroup only makes a copy not a new scene
WindowGroup("1") {
ToggleView(vm: AStoragePlace.getAViewModel(id: "1")!)
.frame(width: 200, height: 200)
}
.commands {
ContentCommands(vm: AStoragePlace.getAViewModel(id: "1")!)
}.handlesExternalEvents(matching: Set(arrayLiteral: "1"))
//To open this go to File>New>New 2 Window
WindowGroup("2") {
ToggleView(vm: AStoragePlace.getAViewModel(id: "2")!)
.frame(width: 200, height: 200)
}
.commands {
ContentCommands(vm: AStoragePlace.getAViewModel(id: "2")!)
}.handlesExternalEvents(matching: Set(arrayLiteral: "2"))
}
}
struct ToggleView: View {
#Environment(\.openURL) var openURL
#ObservedObject var vm: ViewModel
var body: some View {
VStack{
//Makes copies of the window/scene
Button("new-window-of type \(vm.id)", action: {
//appname needs to be a registered url in info.plist
//Info Property List>Url types>url scheme>item 0 == appname
//Info Property List>Url types>url identifier == appname
if let url = URL(string: "WindowSample://\(vm.id)") {
openURL(url)
}
})
//Toggle the state
Toggle(isOn: $vm.toggleState, label: {
Text("Some State \(vm.id)")
})
}
}
}
I'm trying to create NavigationLink in MacBook touchBar with help of SwiftUI. Actually with my piece of code, the button is shown in touchbar, but unfortunately the link doesn't work.
NavigationView {
.touchBar {
NavigationLink(destination: BookView()) {
Text("GoToBook")
}
}
}
struct BookView: View {
var body: some View {
Text("Hello")
}
}
Try instead with Button in touchBar activating NavigationLink programmatically, like below
#State private var isActive = false
...
// below in body
NavigationView {
SomeView() // << your view here
.background(NavigationLink(destination: BookView(), isActive: $isActive) {
EmptyView()
} // hidden link
)
.touchBar {
Button("GoToBook") { self.isActive.toggle() } // activate link
}
}
How can I transition from one View to another? Is there push / pop like in UIKit? Do I have to use a NavigationView and if so how?
Using a NavigationView
NavigationViews are tied to NavigationButton (AFAIK that is the only way to trigger a segue). Here is a simple example where the main view can transition to a detail view.
struct DetailView : View {
let value: String
var body : some View {
Text("Full View: \(value)")
}
}
struct MainView : View {
var body : some View {
NavigationView {
NavigationButton(destination: DetailView(value: "Hello World"),
label: { Text("Click Me") })
}
}
}
This will automatically handle transitions and add a back button.
Using State
Another approach is to use a stateful variable to determine if the child view is displayed. Here is another simple example:
struct DetailView : View {
let value: String
let onDone: () -> Void
var body : some View {
VStack {
Text("Full View: \(value)")
Button(action: onDone, label: { Text("Back") })
}
}
}
struct MainView : View {
#State var displaySubview = false
var body : some View {
VStack {
if displaySubview {
DetailView(value: "Hello World") {
self.displaySubview = false
}
} else {
Button(action: {
self.displaySubview = true
}, label: { Text("Click Me") })
}
}
}
}
This approach requires you to implement more of the UI elements, but it also allows for more control over views.
It works for me
struct ContentView : View {
var body : some View {
NavigationView {
NavigationLink(destination: DetailView(), label: { Text("To Detail")})
}
}}