I toggle a sheet in SwiftUI with the following Button
Button(action: {
self.statusPopoverIsShown.toggle()
})
So the following sheet appears
.sheet(isPresented: self.$popoverIsShown) {
RandomSheet(popoverIsShown: self.$popoverIsShown)
}
Then I have a button inside the RandomSheetto dismiss the sheet (sets the popoverIsShown to false). Everything works fine.
But when I start using the app in splitscreen or somehow change the sizeclass SwiftUI transforms the sheet to a fullscreen iPhone-like sheet and the dismiss button/the binding does not work anymore.
Is there any solution to avoid this and keep the binding stable?
The following works with any size class changes. Tested with Xcode 12 / iOS 14
struct TestSheet: View {
#State private var popoverIsShown = false
var body: some View {
Button("Show Sheet") {
self.popoverIsShown = true
}
.sheet(isPresented: self.$popoverIsShown) {
RandomSheet(popoverIsShown: self.$popoverIsShown)
}
}
}
struct RandomSheet: View {
#Binding var popoverIsShown: Bool
var body: some View {
Button("Close") { self.popoverIsShown = false }
}
}
Related
Scenario:
RootScreen presents DateScreen modally though .sheet
DateScreen has a DatePicker with CompactDatePickerStyle() and a button to dismiss the modal
User opens the DatePicker
User taps the DatePicker to bring up the NumPad for manual keyboard input
User presses the button to dismiss the modal
SwiftUI will think the .sheet got dismissed, but in reality, only the DatePicker's modal got dismissed.
Minimum code example:
struct DateScreen: View {
#Binding var isPresented: Bool
#State var date: Date = Date()
var body: some View {
NavigationView {
VStack {
DatePicker("", selection: $date, displayedComponents: [.hourAndMinute])
.datePickerStyle(CompactDatePickerStyle())
}
.navigationBarItems(leading: Button("Dismiss") {
isPresented = false
})
}
}
}
#main
struct Main: App {
#UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
#State var isPresenting: Bool = false
var body: some Scene {
WindowGroup {
Button("Present modal", action: {
isPresenting = true
})
.sheet(isPresented: $isPresenting, content: {
DateScreen(isPresented: $isPresenting)
})
}
}
}
Gif showing the broken behavior:
Note, if the user doesn't open the NumPad, it seems to work well.
The only workaround I found is to ignore SwiftUI and go back to UIKit to do the dismissal.
Instead of isPresented = false I have to do UIApplication.shared.windows.first?.rootViewController?.dismiss(animated: true).
For iOS 15 this works to dismiss the sheet and doesn't generate the warning:
'windows' was deprecated in iOS 15.0: Use UIWindowScene.windows on a relevant window scene instead
code:
UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.compactMap({$0 as? UIWindowScene})
.first?
.windows
.first { $0.isKeyWindow }?
.rootViewController?
.dismiss(animated: true)
This is problem of provided code - the State is in Scene instead of view - state is not designed to update scene. The correct SwiftUI solution is to move everything from scene to a view and have only one root view there, ie.
Tested with Xcode 13.4 / iOS 15.5
#main
struct Main: App {
#UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
var body: some Scene {
WindowGroup {
ContentView() // << window root view, the one !!
}
}
}
struct ContentView: View {
#State var isPresenting: Bool = false
var body: some View {
Button("Present modal", action: {
isPresenting = true
})
.sheet(isPresented: $isPresenting, content: {
DateScreen(isPresented: $isPresenting)
})
}
}
// no more changes needed
I'm trying to create a IOS app with SwiftUI that uses NavigationViewand hides the Navigation Bar on the first view (and only on the first one).
So I created an ObservableObject
class NavBarShowViewModel: ObservableObject {
#Published var isHidden: Bool = true
}
and in my Content View
struct ContentView: View {
#ObservedObject var navBarShowViewModel = NavBarShowViewModel()
var body: some View {
NavigationView {
Home()
.navigationBarHidden(self.navBarShowViewModel.isHidden)
}
.environmentObject(self.navBarShowViewModel)
}
}
Now in Home I have:
struct Home: View {
#EnvironmentObject var navBarShowViewModel: NavBarShowViewModel
var body: some View {
VStack {
HStack {
NavigationLink(destination: FirstPage()) {
Text("Go!")
}
Text("Hello World")
Spacer()
}
.navigationBarTitle("Home")
}
.onAppear(perform: {
self.navBarShowViewModel.isHidden = true
})
}
}
Now FirstPage() has the exact structure of Home(), except that has a different title
.navigationBarTitle("First Page")
and onAppear has the following code:
.onAppear(perform: {
self.navBarShowViewModel.isHidden = false
})
With this setup, the app works.
But if inside FirstPage() I navigate further, for example going to SecondPage() (which is for sake of simplicity, identical to FirstPage() with a different title) and then hitting back until I return to Home, onAppear here on Home() is not called, so it shows the navigation bar title.
Could someone explain this?
It is about how SwiftUI engine tracks views and if it really appears... anyway, what it is can be determined as it is how child views appear/disappear on navigation stack, so possible solution is to add onDisappear in FirstPage, like
struct FirstPage: View {
#EnvironmentObject var navBarShowViewModel: NavBarShowViewModel
var body: some View {
... other code here
.onAppear(perform: {
self.navBarShowViewModel.isHidden = false
})
.onDisappear(perform: {
self.navBarShowViewModel.isHidden = true
})
}
}
Tested with Xcode 12.4 / iOS 14.4
we have several SwiftUI screens that are presented as sheet.
all of then can be dismissed by clicking a button.
so basically all of them have these 2 in common:
#Environment(\.presentationMode) var presentationMode
func dismiss() {
presentationMode.wrappedValue.dismiss()
}
how can i declare them only once and just reuse them only in specific views?
i cannot use inheritance since they are stucts, extensions cannot contain state (except using a holder struct) and would add these to all instances of the same view type.
The .presentationMode is available throughout current view hierarchy, so we can use this feature to wrap & manage dismiss in some modifier.
Here is a demo of solution based on button style, so any button can be specified as dismissing and it will dismiss current presentation.
Prepared with Xcode 12.1 / iOS 14.1
struct TestReuseDismissed: View {
#State private var isActive = false
var body: some View {
Button("Show Sheet") {
isActive = true
}
.sheet(isPresented: $isActive) {
Button("Dismiss", action: {
// do something before dismiss here !!
})
.buttonStyle(DismissButtonStyle())
}
}
}
struct DismissButtonStyle: PrimitiveButtonStyle {
#Environment(\.presentationMode) var presentationMode
func makeBody(configuration: Configuration) -> some View {
Button(action: {
configuration.trigger()
dismiss()
}) { configuration.label }
}
func dismiss() {
presentationMode.wrappedValue.dismiss()
}
}
Whenever my code gets too big, SwiftUI starts acting weird and generates an error:
"The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions"
So I started breaking up my code into Extracted Subviews, one of the problems I came across is how to dismiss a view from a subtracted subview.
Example: we have here LoginContentView this view contains a button when the button is clicked it will show the next view UsersOnlineView.
struct LoginContentView: View {
#State var showUsersOnlineView = false
var body: some View {
Button(action: {
self.showUsersOnlineView = true
}) {
Text("Show the next view")
}
.fullScreenCover(isPresented: $showUsersOnlineView, content: {
UsersOnlineView()
})
}
On the other hand, we have a button that is extracted to subview, to dismiss the modal and go back to the original view:
import SwiftUI
struct UsersOnlineView: View {
var body: some View {
ZStack {
VStack {
CloseViewButton()
}
}
}
}
struct CloseViewButton: View {
var body: some View {
Button(action: {
// Close the Modal
}) {
Text("Close the view")
}
}
}
Give the sbview the state property that defines if the view is shown.
struct CloseViewButton: View {
#Binding var showView: Bool
var body: some View {
Button(
ShowView = false
}) {
Text("Close the view")
}
}
}
When you use the sub view give it the property
CloseButtonView(showView: $showOnlineView)
To allow the sub view to change the isShown property it needs to get a binding.
On the presentation mode. I think this only works with Swiftui presentations like sheet and alert.
The simplest solution for this scenario is to use presentationMode environment variable:
struct CloseViewButton: View {
#Environment(\.presentationMode) var presentationMode
var body: some View {
Button(action: {
presentationMode.wrappedValue.dismiss()
}) {
Text("Close the view")
}
}
}
Tested with Xcode 12.1 / iOS 14.1
I want to achieve the function. Like, "Look up" view that is from Apple.
My aim is when the sheet view push another view by navigation, the user can tap the navigation item button to close the sheet view. Like, this below gif.
I try to achieve this function.
I found a problem that is when the user tap the "Done" button. The App doesn't close the sheet view. It only pop the view to parent view. Like, this below gif.
This is my code.
import SwiftUI
struct ContentView: View {
#State var isShowSheet = false
var body: some View {
Button(action: {
self.isShowSheet.toggle()
}) {
Text("Tap to show the sheet")
}.sheet(isPresented: $isShowSheet) {
NavView()
}
}
}
struct NavView: View {
var body: some View {
NavigationView {
NavigationLink(destination: NavSubView()) {
Text("Enter Sub View")
}
} .navigationViewStyle(StackNavigationViewStyle())
}
}
struct NavSubView: View {
#Environment(\.presentationMode) var presentationMode
var body: some View {
Text("Hello")
.navigationBarItems(trailing:
Button(action: {
self.presentationMode.wrappedValue.dismiss()
}){
Text("Done")
}
)
}
}
How did I achieve this function? :)
Please help me, thank you. :)
UPDATE: Restored original version - provided below changes should be done, as intended, to the topic starter's code. Tested as worked with Xcode 13 / iOS 15
As navigation in sheet might be long enough and closing can be not in all navigation subviews, I prefer to use environment to have ability to specify closing feature only in needed places instead of passing binding via all navigation stack.
Here is possible approach (tested with Xcode 11.2 / iOS 13.2)
Define environment key to store sheet state
struct ShowingSheetKey: EnvironmentKey {
static let defaultValue: Binding<Bool>? = nil
}
extension EnvironmentValues {
var showingSheet: Binding<Bool>? {
get { self[ShowingSheetKey.self] }
set { self[ShowingSheetKey.self] = newValue }
}
}
Set this environment value to root of sheet content, so it will be available in any subview when declared
}.sheet(isPresented: $isShowSheet) {
NavView()
.environment(\.showingSheet, self.$isShowSheet)
}
Declare & use environment value only in subview where it is going to be used
struct NavSubView: View {
#Environment(\.showingSheet) var showingSheet
var body: some View {
Text("Hello")
.navigationBarItems(trailing:
Button("Done") {
self.showingSheet?.wrappedValue = false
}
)
}
}
I haven't tried SwiftUI ever, but I came from UIKit + RxSwift, so I kinda know how binding works. I read quite a bit of sample codes from a SwiftUI Tutorial, and the way you dismiss a modal is actually correct, but apparently not for a navigation stack.
One way I learned just now is use a #Binding var. This might not be the best solution, but it worked!
So you have this $isShowSheet in your ContentView. Pass that object to your NavView struct by declaring a variable in that NavView.
ContentView
.....
}.sheet(isPresented: $isShowSheet) {
NavView(isShowSheet: self.$isShowSheet)
}
NavView
struct NavView: View {
#Binding var isShowSheet: Bool
var body: some View {
NavigationView {
NavigationLink(destination: NavSubView(isShowSheet: self.$isShowSheet)) {
Text("Enter Sub View")
}
} .navigationViewStyle(StackNavigationViewStyle())
}
}
and finally, do the same thing to your subView.
NavSubView
struct NavSubView: View {
#Environment(\.presentationMode) var presentationMode
#Binding var isShowSheet: Bool
var body: some View {
Text("Hello")
.navigationBarItems(trailing:
Button(action: {
//self.presentationMode.projectedValue.wrappedValue.dismiss()
self.isShowSheet = false
}){
Text("Done")
}
)
}
}
Now as you can see, you just need to send a new signal to that isShowSheet binding var - false.
self.isShowSheet = false
Voila!
Here's an improved version of Asperi's code from above since they won't accept my edit. Main credit goes to them.
As navigation in sheet might be long enough and closing can be not in all navigation subviews, I prefer to use environment to have ability to specify closing feature only in needed places instead of passing binding via all navigation stack.
Here is possible approach (tested with Xcode 13 / iOS 15)
Define environment key to store sheet state
struct ShowingSheetKey: EnvironmentKey {
static let defaultValue: Binding<Bool>? = nil
}
extension EnvironmentValues {
var isShowingSheet: Binding<Bool>? {
get { self[ShowingSheetKey.self] }
set { self[ShowingSheetKey.self] = newValue }
}
}
Set this environment value to root of sheet content, so it will be available in any subview when declared
#State var isShowingSheet = false
...
Button("open sheet") {
isShowingSheet?.wrappedValue = true
}
// note no $ in front of isShowingSheet
.sheet(isPresented: isShowingSheet ?? .constant(false)) {
NavView()
.environment(\.isShowingSheet, self.$isShowingSheet)
}
Declare & use environment value only in subview where it is going to be used
struct NavSubView: View {
#Environment(\.isShowingSheet) var isShowingSheet
var body: some View {
Text("Hello")
.navigationBarItems(trailing:
Button("Done") {
isShowingSheet?.wrappedValue = false
}
)
}
}