SwiftUI-在 SwiftUI 中是否有一个 popViewController 等价物？

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It seems that a ton of basic navigation functionality is super buggy, which is disappointing and may be worth walking away from for now to save hours of frustration. For me, PresentationButton is the only one that works. TabbedView tabs don't work properly, and NavigationButton doesn't work for me at all. Sounds like YMMV if NavigationButton works for you.

I'm hoping that they fix it at the same time they fix autocomplete, which would give us much better insight as to what is available to us. In the meantime, I'm reluctantly coding around it and keeping notes for when fixes come out. It sucks to have to figure out if we're doing something wrong or if it just doesn't work, but that's beta for you!

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EDIT: This answer over here is better than mine, but both work: SwiftUI dismiss modal

What you really want (or should want) is a modal presentation, which several people have mentioned here. If you go that path, you definitely will need to be able to programmatically dismiss the modal, and Erica Sadun has a great example of how to do that here: https://ericasadun.com/2019/06/16/swiftui-modal-presentation/

Given the difference between declarative coding and imperative coding, the solution there may be non-obvious (toggling a bool to false to dismiss the modal, for example), but it makes sense if your model state is the source of truth, rather than the state of the UI itself.

Here's my quick take on Erica's example, using a binding passed into the TestModal so that it can dismiss itself without having to be a member of the ContentView itself (as Erica's is, for simplicity).

struct TestModal: View {
@State var isPresented: Binding<Bool>


var body: some View {
Button(action: { self.isPresented.value = false }, label: { Text("Done") })
}
}


struct ContentView : View {
@State var modalPresented = false


var body: some View {
NavigationView {
Text("Hello World")
.navigationBarTitle(Text("View"))
.navigationBarItems(trailing:
Button(action: { self.modalPresented = true }) { Text("Show Modal") })
}
.presentation(self.modalPresented ? Modal(TestModal(isPresented: $modalPresented)) {
self.modalPresented.toggle()
} : nil)
}
}

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Update: the NavigationDestinationLink API in this solution has been deprecated as of iOS 13 Beta 5. It is now recommended to use NavigationLink with an isActive binding.

I figured out a solution for programmatic pushing/popping of views in a NavigationView using NavigationDestinationLink.

Here's a simple example:

import Combine
import SwiftUI


struct DetailView: View {
var onDismiss: () -> Void


var body: some View {
Button(
"Here are details. Tap to go back.",
action: self.onDismiss
)
}
}


struct MainView: View {
var link: NavigationDestinationLink<DetailView>
var publisher: AnyPublisher<Void, Never>


init() {
let publisher = PassthroughSubject<Void, Never>()
self.link = NavigationDestinationLink(
DetailView(onDismiss: { publisher.send() }),
isDetail: false
)
self.publisher = publisher.eraseToAnyPublisher()
}


var body: some View {
VStack {
Button("I am root. Tap for more details.", action: {
self.link.presented?.value = true
})
}
.onReceive(publisher, perform: { _ in
self.link.presented?.value = false
})
}
}


struct RootView: View {
var body: some View {
NavigationView {
MainView()
}
}
}

I wrote about this in a blog post here.

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instead of NavigationButton use Navigation DestinationLink

but You should import Combine

struct AView: View {
var link: NavigationDestinationLink<BView>
var publisher: AnyPublisher<Void, Never>


init() {
let publisher = PassthroughSubject<Void, Never>()
self.link = NavigationDestinationLink(
BView(onDismiss: { publisher.send() }),
isDetail: false
)
self.publisher = publisher.eraseToAnyPublisher()
}


var body: some View {
NavigationView {
Button(action:{
self.link.presented?.value = true




}) {
Text("Go to B")
}.onReceive(publisher, perform: { _ in
self.link.presented?.value = false
})
}
}
}


struct BView: View {
var onDismiss: () -> Void
var body: some View {
Button(action: self.onDismiss) {
Text("Come back to A")
}
}
}

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There is now a way to programmatically pop in a NavigationView, if you would like. This is in beta 5.

Notice that you don't need the back button. You could programmatically trigger the showSelf property in the DetailView any way you like. And you don't have to display the "Push" text in the master. That could be an EmptyView(), thereby creating an invisible segue.

(The new NavigationLink functionality takes over the deprecated NavigationDestinationLink)

import SwiftUI


struct ContentView: View {
var body: some View {
NavigationView {
MasterView()
}
}
}


struct MasterView: View {
@State var showDetail = false


var body: some View {
VStack {
NavigationLink(destination: DetailView(showSelf: $showDetail), isActive: $showDetail) {
Text("Push")
}
}
}
}


struct DetailView: View {
@Binding var showSelf: Bool


var body: some View {
Button(action: {
self.showSelf = false
}) {
Text("Pop")
}
}
}


#if DEBUG
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
#endif

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Modify your BView struct as follows. The button will perform just as popViewController did in UIKit.

struct BView: View {
@Environment(\.presentationMode) var mode: Binding<PresentationMode>
var body: some View {
Button(action: { self.mode.wrappedValue.dismiss() })
{ Text("Come back to A") }
}
}

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This seems to work for me on watchOS (haven't tried on iOS):

@Environment(\.presentationMode) var presentationMode

And then when you need to pop

self.presentationMode.wrappedValue.dismiss()

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In the destination pass the view you want to redirect, and inside block pass data you to pass in another view.

NavigationLink(destination: "Pass the particuter View") {
Text("Push")
}

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Below works for me in XCode11 GM

self.myPresentationMode.wrappedValue.dismiss()

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Use @Environment(\.presentationMode) var presentationMode to go back previous view. Check below code for more understanding.

import SwiftUI


struct ContentView: View {




var body: some View {


NavigationView {
ZStack {
Color.gray.opacity(0.2)


NavigationLink(destination: NextView(), label: {Text("Go to Next View").font(.largeTitle)})
}.navigationBarTitle(Text("This is Navigation"), displayMode: .large)
.edgesIgnoringSafeArea(.bottom)
}
}
}


struct NextView: View {
@Environment(\.presentationMode) var presentationMode
var body: some View {
ZStack {
Color.gray.opacity(0.2)
}.navigationBarBackButtonHidden(true)
.navigationBarItems(leading: Button(action: {
self.presentationMode.wrappedValue.dismiss()
}, label: { Image(systemName: "arrow.left") }))
.navigationBarTitle("", displayMode: .inline)
}
}




struct NameRow: View {
var name: String
var body: some View {
HStack {
Image(systemName: "circle.fill").foregroundColor(Color.green)
Text(name)
}
}
}


struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}

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With State Variables. Try that.

struct ContentViewRoot: View {
@State var pushed: Bool = false
var body: some View {
NavigationView{
VStack{
NavigationLink(destination:ContentViewFirst(pushed: self.$pushed), isActive: self.$pushed) { EmptyView() }
.navigationBarTitle("Root")
Button("push"){
self.pushed = true
}
}
}
.navigationViewStyle(StackNavigationViewStyle())
}
}




struct ContentViewFirst: View {
@Binding var pushed: Bool
@State var secondPushed: Bool = false
var body: some View {
VStack{
NavigationLink(destination: ContentViewSecond(pushed: self.$pushed, secondPushed: self.$secondPushed), isActive: self.$secondPushed) { EmptyView() }
.navigationBarTitle("1st")
Button("push"){
self.secondPushed = true;
}
}
}
}






struct ContentViewSecond: View {
@Binding var pushed: Bool
@Binding var secondPushed: Bool


var body: some View {
VStack{
Spacer()
Button("PopToRoot"){
self.pushed = false
} .navigationBarTitle("2st")


Spacer()
Button("Pop"){
self.secondPushed = false
} .navigationBarTitle("1st")
Spacer()
}
}
}

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You can also do it with .sheet

.navigationBarItems(trailing: Button(action: {
self.presentingEditView.toggle()
}) {
Image(systemName: "square.and.pencil")
}.sheet(isPresented: $presentingEditView) {
EditItemView()
})

In my case I use it from a right navigation bar item, then you have to create the view (EditItemView() in my case) that you are going to display in that modal view.

https://developer.apple.com/documentation/swiftui/view/sheet(ispresented:ondismiss:content:)