I have two views ListView and DetailView
ListView:
#EnvironmentObject var userData: UserData
var body: some View {
VStack {
ForEach(userData.packs) { pack in
if pack.added {
NavigationLink(destination: DetailView(packIndex: self.userData.packs.firstIndex(where: { $0.id == pack.id })!)) {
MyRowViewDoesntMatter(pack: pack)
}
}
}
}
.padding(.horizontal)
}
DetailView:
#EnvironmentObject var userData: UserData
var packIndex: Int
VStack {
List {
VStack {
.... some Vies ... doesn't matter
.navigationBarItems(trailing:
THE PROBLEM IS HERE (BELOW)
Button(action: {
self.userData.packs[self.packIndex].added.toggle()
}) {
Image(systemName: self.userData.packs[self.packIndex].added ? "plus.circle.fill" : "plus.circle")
}
...
The problem is when I click on button in the navigationBarItems in DetailView. The "added" property of the "#EnvironmentObject var userData: UserData" is updated and the user's screen is going back (to the RowView). I fond out that the problem with EnvironmentObject, because the data is updated and View tries to rerender (?) that is why it pushes me back?
How to fix it? I want to stay at the DetailView screen after clicking the button.
P.S. I need to use EnvironmentObject type because then when I go back I need to see the results.
Thank you very much!
Here is possible approach (by introducing some kind of selection). As NavigationView does not allow to remove link from stack (as identifier of stacked navigation), probably also worth considering separate view model for DetailView to be applied into common container on finish editing.
Tested with Xcode 11.4 / iOS 13.4.
Some replication of your code, used for testing:
struct ListView: View {
#EnvironmentObject var userData: PushBackUserData
#State private var selectedPack: Pack? = nil
var body: some View {
NavigationView {
VStack {
ForEach(Array(userData.packs.enumerated()), id: \.element.id) { i, pack in
NavigationLink("Pack \(pack.id)", destination:
DetailView(pack: self.$selectedPack)
.onAppear {
self.selectedPack = pack
}
.onDisappear {
self.userData.packs[i].added = self.selectedPack?.added ?? false
}
).isHidden(!pack.added)
}
}
.padding(.horizontal)
}
}
}
struct DetailView: View {
#Binding var pack: Pack?
var body: some View {
VStack {
List {
VStack {
Text("Pack \(pack?.id ?? "<none>")")
}
}
.navigationBarItems(trailing:
Button(action: {
self.pack?.added.toggle()
}) {
Image(systemName: pack?.added ?? false ? "plus.circle.fill" : "plus.circle")
}
)
}
}
}
just convenient helper extension
extension View {
func isHidden(_ hidden: Bool) -> some View {
Group {
if hidden { self.hidden() }
else { self }
}
}
}
Related
I want to present the two destinations view in full screen mode from a single view.
Below is a sample of my code. Seem that the function only works for single presentation, if I have a second fullScreenCover defined, the first fullScreenCover didn't work properly.Is that any workaround at this moment?
import SwiftUI
struct TesFullScreen: View {
init(game : Int){
print(game)
}
var body: some View {
Text("Full Screen")
}
}
ContentView
import SwiftUI
struct ContentView: View {
#State var showFullScreen1 : Bool = false
#State var showFullScreen2 : Bool = false
var body: some View {
NavigationView {
VStack {
Spacer()
Button(action: { self.showFullScreen1 = true }) {
Text("Show Full Screen 1")
}
Button(action: { self.showFullScreen2 = true }) {
Text("Show Full Screen 2")
}
Spacer()
}
.navigationBarTitle("TextBugs", displayMode: .inline)
}
.fullScreenCover(isPresented: self.$showFullScreen1){
TesFullScreen(game: 1)
}
.fullScreenCover(isPresented: self.$showFullScreen2){
TesFullScreen(game: 2)
}
}
}
Not always the accepted answer works (for example if you have a ScrollView with subviews (cells in former days) which holds the buttons, that set the navigational flags).
But I found out, that you also can add the fullScreen-modifier onto an EmptyView. This code worked for me:
// IMPORTANT: Has to be within a container (e.g. VStack, HStack, ZStack, ...)
if myNavigation.flag1 || myNavigation.flag2 {
EmptyView().fullScreenCover(isPresented: $myNavigation.flag1)
{ MailComposer() }
EmptyView().fullScreenCover(isPresented: $myNavigation.flag2)
{ RatingStore() }
}
Usually some same modifier added one after another is ignored. So the simplest fix is to attach them to different views, like
struct FullSContentView: View {
#State var showFullScreen1 : Bool = false
#State var showFullScreen2 : Bool = false
var body: some View {
NavigationView {
VStack {
Spacer()
Button(action: { self.showFullScreen1 = true }) {
Text("Show Full Screen 1")
}
.fullScreenCover(isPresented: self.$showFullScreen1){
Text("TesFullScreen(game: 1)")
}
Button(action: { self.showFullScreen2 = true }) {
Text("Show Full Screen 2")
}
.fullScreenCover(isPresented: self.$showFullScreen2){
Text("TesFullScreen(game: 2)")
}
Spacer()
}
.navigationBarTitle("TextBugs", displayMode: .inline)
}
}
}
Alternate is to have one .fullScreenCover(item:... modifier and show inside different views depending on input item.
The only thing that worked for me was the answer in this link:
https://forums.swift.org/t/multiple-sheet-view-modifiers-on-the-same-view/35267
Using the EmptyView method or other solutions always broke a transition animation on one of the two presentations. Either transitioning to or from that view and depending on what order I chose them.
Using the approach by Lantua in the link which is using the item argument instead of isPresented worked in all cases:
enum SheetChoice: Hashable, Identifiable {
case a, b
var id: SheetChoice { self }
}
struct ContentView: View {
#State var sheetState: SheetChoice?
var body: some View {
VStack {
...
}
.sheet(item: $sheetState) { item in
if item == .a {
Text("A")
} else {
Text("B")
}
}
}
}
The sheetState needs to be optional for it to work.
I'm trying to create a button that not only navigates to another view, but also run a function at the same time. I tried embedding both a NavigationLink and a Button into a Stack, but I'm only able to click on the Button.
ZStack {
NavigationLink(destination: TradeView(trade: trade)) {
TradeButton()
}
Button(action: {
print("Hello world!") //this is the only thing that runs
}) {
TradeButton()
}
}
You can use .simultaneousGesture to do that. The NavigationLink will navigate and at the same time perform an action exactly like you want:
NavigationLink(destination: TradeView(trade: trade)) {
Text("Trade View Link")
}.simultaneousGesture(TapGesture().onEnded{
print("Hello world!")
})
You can use NavigationLink(destination:isActive:label:). Use the setter on the binding to know when the link is tapped. I've noticed that the NavigationLink could be tapped outside of the content area, and this approach captures those taps as well.
struct Sidebar: View {
#State var isTapped = false
var body: some View {
NavigationLink(destination: ViewToPresent(),
isActive: Binding<Bool>(get: { isTapped },
set: { isTapped = $0; print("Tapped") }),
label: { Text("Link") })
}
}
struct ViewToPresent: View {
var body: some View {
print("View Presented")
return Text("View Presented")
}
}
The only thing I notice is that setter fires three times, one of which is after it's presented. Here's the output:
Tapped
Tapped
View Presented
Tapped
NavigationLink + isActive + onChange(of:)
// part 1
#State private var isPushed = false
// part 2
NavigationLink(destination: EmptyView(), isActive: $isPushed, label: {
Text("")
})
// part 3
.onChange(of: isPushed) { (newValue) in
if newValue {
// do what you want
}
}
This works for me atm:
#State private var isActive = false
NavigationLink(destination: MyView(), isActive: $isActive) {
Button {
// run your code
// then set
isActive = true
} label: {
Text("My Link")
}
}
Use NavigationLink(_:destination:tag:selection:) initializer and pass your model's property as a selection parameter. Because it is a two-way binding, you can define didset observer for this property, and call your function there.
struct ContentView: View {
#EnvironmentObject var navigationModel: NavigationModel
var body: some View {
NavigationView {
List(0 ..< 10, id: \.self) { row in
NavigationLink(destination: DetailView(id: row),
tag: row,
selection: self.$navigationModel.linkSelection) {
Text("Link \(row)")
}
}
}
}
}
struct DetailView: View {
var id: Int;
var body: some View {
Text("DetailView\(id)")
}
}
class NavigationModel: ObservableObject {
#Published var linkSelection: Int? = nil {
didSet {
if let linkSelection = linkSelection {
// action
print("selected: \(String(describing: linkSelection))")
}
}
}
}
It this example you need to pass in your model to ContentView as an environment object:
ContentView().environmentObject(NavigationModel())
in the SceneDelegate and SwiftUI Previews.
The model conforms to ObservableObject protocol and the property must have a #Published attribute.
(it works within a List)
I also just used:
NavigationLink(destination: View()....) {
Text("Demo")
}.task { do your stuff here }
iOS 15.3 deployment target.
Given this simple NavigationView:
struct ContentView : View {
var body: some View {
NavigationView {
VStack {
NavigationLink("Push Me", destination: Text("PUSHED VIEW"))
}
}
}
}
Did anyone find a way of disabling the NavigationView animation when a destination view is pushed/popped into/from the stack?
This has been possible in UIKit since iOS2.0! I think it is not too much to ask from the framework. I tried all sorts of modifiers on all views (i.e., the NavigationView container, the destination view, the NavigationLink, etc)
These are some of the modifiers I tried:
.animation(nil)
.transition(.identity)
.transaction { t in t.disablesAnimations = true }
.transaction { t in t.animation = nil }
None made a difference. I did not find anything useful in the EnvironmentValues either :-(
Am I missing something very obvious, or is the functionality just not there yet?
Xcode 11.3:
Right now there is no modifier to disable NavigationView animations.
You can use your struct init() to disable animations, as below:
struct ContentView : View {
init(){
UINavigationBar.setAnimationsEnabled(false)
}
var body: some View {
NavigationView {
VStack {
NavigationLink("Push Me", destination: Text("PUSHED VIEW"))
}
}
}
}
First you need state for the NavigationLink to respond to, then set that state inside a transaction with animations disabled, as follows:
struct ContentView : View {
#State var isActive = false
var body: some View {
NavigationView {
VStack {
NavigationLink(isActive: $isActive, destination: {
Text("PUSHED VIEW")}) {
Text("Push Me")
}
Button("Navigate Without Animation") {
var transaction = Transaction()
transaction.disablesAnimations = true
withTransaction(transaction) {
isActive = true
}
}
}
}
}
}
I recently created an open source project called swiftui-navigation-stack (https://github.com/biobeats/swiftui-navigation-stack) that contains the NavigationStackView, a view that mimics the navigation behaviours of the standard NavigationView adding some useful features. For example, you could use the NavigationStackView and disable the transition animations as requested by Kontiki in the question. When you create the NavigationStackView just specify .none as transitionType:
struct ContentView : View {
var body: some View {
NavigationStackView(transitionType: .none) {
ZStack {
Color.yellow.edgesIgnoringSafeArea(.all)
PushView(destination: View2()) {
Text("PUSH")
}
}
}
}
}
struct View2: View {
var body: some View {
ZStack {
Color.green.edgesIgnoringSafeArea(.all)
PopView {
Text("POP")
}
}
}
}
PushView and PopView are two views that allow you push and pop views (similar to the SwiftUI NavigationLink). Here is the complete example:
import SwiftUI
import NavigationStack
struct ContentView : View {
var body: some View {
NavigationStackView(transitionType: .none) {
ZStack {
Color.yellow.edgesIgnoringSafeArea(.all)
PushView(destination: View2()) {
Text("PUSH")
}
}
}
}
}
struct View2: View {
var body: some View {
ZStack {
Color.green.edgesIgnoringSafeArea(.all)
PopView {
Text("POP")
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
The result is:
It would be great if you guys joined me in improving this open source project.
I would like to be able to show a new view when a button is pressed on one of my views.
From the tutorials I have looked at and other answered questions here it seems like everyone is using navigation button within a navigation view, unless im mistaken navigation view is the one that gives me a menu bar right arrows the top of my app so I don't want that. when I put the navigation button in my view that wasn't a child of NavigationView it was just disabled on the UI and I couldn't click it, so I guess I cant use that.
The other examples I have seen seem to use presentation links / buttons which seem to show a sort of pop over view.
Im just looking for how to click a regular button and show another a view full screen just like performing a segue used to in the old way of doing things.
Possible solutions
1.if you want to present on top of current view(ex: presentation style in UIKit)
struct ContentView: View {
#State var showingDetail = false
var body: some View {
Button(action: {
self.showingDetail.toggle()
}) {
Text("Show Detail")
}.sheet(isPresented: $showingDetail) {
DetailView()
}
}
}
2.if you want to reset current window scene stack(ex:after login show home screen)
Button(action: goHome) {
HStack(alignment: .center) {
Spacer()
Text("Login").foregroundColor(Color.white).bold()
Spacer()
}
}
func goHome() {
if let window = UIApplication.shared.windows.first {
window.rootViewController = UIHostingController(rootView: HomeScreen())
window.makeKeyAndVisible()
}
}
3.push new view (ex: list->detail, navigation controller of UIKit)
struct ContentView: View {
var body: some View {
NavigationView {
VStack {
NavigationLink(destination: DetailView()) {
Text("Show Detail View")
}.navigationBarTitle("Navigation")
}
}
}
}
4.update the current view based on #state property, (ex:show error message on login failure)
struct ContentView: View {
#State var error = true
var body: some View {
...
... //login email
.. //login password
if error {
Text("Failed to login")
}
}
}
For simple example you can use something like below
import SwiftUI
struct ExampleFlag : View {
#State var flag = true
var body: some View {
ZStack {
if flag {
ExampleView().tapAction {
self.flag.toggle()
}
} else {
OtherExampleView().tapAction {
self.flag.toggle()
}
}
}
}
}
struct ExampleView: View {
var body: some View {
Text("some text")
}
}
struct OtherExampleView: View {
var body: some View {
Text("other text")
}
}
but if you want to present more view this way looks nasty
You can use stack to control view state without NavigationView
For Example:
class NavigationStack: BindableObject {
let didChange = PassthroughSubject<Void, Never>()
var list: [AuthState] = []
public func push(state: AuthState) {
list.append(state)
didChange.send()
}
public func pop() {
list.removeLast()
didChange.send()
}
}
enum AuthState {
case mainScreenState
case userNameScreen
case logginScreen
case emailScreen
case passwordScreen
}
struct NavigationRoot : View {
#EnvironmentObject var state: NavigationStack
#State private var aligment = Alignment.leading
fileprivate func CurrentView() -> some View {
switch state.list.last {
case .mainScreenState:
return AnyView(GalleryState())
case .none:
return AnyView(LoginScreen().environmentObject(state))
default:
return AnyView(AuthenticationView().environmentObject(state))
}
}
var body: some View {
GeometryReader { geometry in
self.CurrentView()
.background(Image("background")
.animation(.fluidSpring())
.edgesIgnoringSafeArea(.all)
.frame(width: geometry.size.width, height: geometry.size.height,
alignment: self.aligment))
.edgesIgnoringSafeArea(.all)
.onAppear {
withAnimation() {
switch self.state.list.last {
case .none:
self.aligment = Alignment.leading
case .passwordScreen:
self.aligment = Alignment.trailing
default:
self.aligment = Alignment.center
}
}
}
}
.background(Color.black)
}
}
struct ExampleOfAddingNewView: View {
#EnvironmentObject var state: NavigationStack
var body: some View {
VStack {
Button(action:{ self.state.push(state: .emailScreen) }){
Text("Tap me")
}
}
}
}
struct ExampleOfRemovingView: View {
#EnvironmentObject var state: NavigationStack
var body: some View {
VStack {
Button(action:{ self.state.pop() }){
Text("Tap me")
}
}
}
}
In my opinion this bad way, but navigation in SwiftUI much worse
I've got a very simple VStack, based directly off of one of Paul Hudson's excellent SwiftUI samples. There are two lines of Text, one hidden. There's a method to toggle an #State var which controls the hidden Text.
If I call that function from within the VStack, it animates properly. If I call it from a navigationBarItems, it loses the animation. Am I missing something about how views are composed?
struct ContentView: View {
#State var showDetails = false
func toggleDetails() { withAnimation { self.showDetails.toggle() } }
var body: some View {
NavigationView() {
VStack {
Button(action: { self.toggleDetails() }) { Text("Tap to show details") }
if showDetails { Text("Details go here.") }
}
.navigationBarTitle(Text("Nav Bar"))
.navigationBarItems(trailing:
Button(action: { self.toggleDetails() }) {
Text("Details")
})
}
}
}
#if DEBUG
struct ContentView_Previews : PreviewProvider {
static var previews: some View {
ContentView()
}
}
#endif
Beta 5 Update
It seems beta 5 fixed this problem. Workaround no longer needed.
Workaround for beta 4 and previous versions
I think the reason it does not work, is because you are calling withAnimation from a different branch of the view tree. The "Details" button and the views that need to be animated are on different branches of the hierarchy. I am just guessing, but it seems to be supported by the workaround I posted here.
If instead of using explicit animations (i.e., withAnimation), you use implicit animations on both the VStack and the Text, it works:
struct ContentView: View {
#State var showDetails = false
func toggleDetails() { self.showDetails.toggle() }
var body: some View {
NavigationView() {
VStack {
Button(action: { self.toggleDetails() }) { Text("Tap to show details") }
if showDetails {
Text("Details go here.").animation(.basic())
}
}
.animation(.basic())
.navigationBarTitle(Text("Nav Bar"))
.navigationBarItems(trailing:
Button(action: {
self.toggleDetails()
}) { Text("Details") })
}
}
}