I am trying to make an effect where the navigation bar and tab bar fade out while the user is scrolling, and then fade in when the user taps on the screen. This is the code I have so far:
import SwiftUI
struct QPageView: View {
#State private var searching = ""
#State private var isScrolling: Visibility = .visible
var body: some View {
List {
ForEach(0..<40) {
Text("\($0)")
}
}
.navigationTitle("Hello")
.navigationBarTitleDisplayMode(.inline)
.searchable(text: $searching, placement: .navigationBarDrawer(displayMode: .always))
.toolbar(isScrolling, for: .navigationBar)
.toolbar(isScrolling, for: .tabBar)
.simultaneousGesture(DragGesture().onChanged { _ in
withAnimation {
isScrolling = .hidden
}
})
.simultaneousGesture(TapGesture().onEnded { _ in
withAnimation {
isScrolling = .visible
}
})
}
}
struct PageView_Previews: PreviewProvider {
static var previews: some View {
PageView()
}
}
struct PageView: View {
var body: some View {
TabView {
NavigationView {
NavigationLink(destination: QPageView()) {
Text("Click Me")
}
}
.tabItem {
Label("Hey", systemImage: "book.fill")
}
}
}
}
This is the current effect I'm getting. I am getting a sliding animation, which is not the desired effect I am going for.
Anyone know how I can accomplish a fading effect? I cannot seem to figure it out using withAnimation. Any help would be appreciated.
Related
So here's my problem:
I have a main view with a navigation view and then the list view.
The colors are just to distinguish different views.
At first everything works as intended but as soon as the app goes into the background (aka Home Screen) and then back to active again my list view is bugging out.
The whole list moves down roughly 3 times the height of one cell.
The main views background is blue so it's not the whole list which gets moved.
I tried to use PlainListStyle() and GroupedListStyle() but the header as well moves down.
If I use one of the links in the bottom blue bar (yeah I know, dumb choice of color and changed in the code snippet below) and then navigate back the list is back in it's original shape.
Edit:
Adding anything to the Stack above the list fixes the problem.
A text or a rectangle is all it takes.
As a workaround a rectangle with heigh 0.1 and the same color as the navigation bar is sufficient.
But any ideas to fix it permanently would be appreciated!
What it should look like:
What it looks like after the app has been in the background:
import SwiftUI
struct TestListView: View
{
#State var dummyList: [DummyCell] = []
#Environment(\.scenePhase) var scenePhase
#State private var listBlur : CGFloat = 0.0
var body: some View
{
List
{
ForEach(dummyList)
{ item in
item
.listRowBackground(Color.yellow)
}
.onDelete
{ indexSet in
dummyList.remove(atOffsets: indexSet)
}
.onMove
{ indices, newOffsets in
dummyList.move(fromOffsets: indices, toOffset: newOffsets)
}
}
.background
{
Color.green
}
.onAppear
{
if dummyList.isEmpty
{
let testData = testData()
testData.forEach
{
daten in
dummyList.append(daten)
}
}
}
.onDisappear { print("List OnDisappear") }
.blur(radius: listBlur)
.onChange(of: scenePhase)
{
newPhase in
if newPhase == .active
{
print("List Active")
dummyList.removeAll()
let list = testData()
list.forEach { cell in
dummyList.append(cell)
}
listBlur = 0
}
else if newPhase == .inactive
{
print("List Inactive")
listBlur = 10.0
}
}
}
private func testData() -> [DummyCell]
{
var list : [DummyCell] = []
for index in 0..<20
{
list.append(DummyCell(dummyNumber: index))
}
return list
}
}
struct TestListView_Previews: PreviewProvider {
static var previews: some View {
TestListView()
}
}
import SwiftUI
struct MainView: View {
#Environment(\.scenePhase) var scenePhase
var body: some View {
ZStack
{
NavigationView
{
VStack
{
// Main View
TestListView()
.navigationBarTitle("listTest", displayMode: .inline)
.navigationBarItems(leading: EditButton())
.navigationBarItems(trailing: EditButton())
// Footer
Footer()
}
.background
{
Color.green
}
}
.navigationBarColor(UIColor(Color.orange))
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
MainView()
}
}
struct Footer: View
{
var body: some View
{
HStack
{
NavigationLink(destination: Text("SomeView"), label: {
Text("SomeView")
})
.padding(.top)
.padding(.leading)
Spacer()
NavigationLink(destination: Text("SomeOtherView"), label: {
Text("SomeOtherView")
})
.padding(.top)
.padding(.trailing)
}
}
}
Consider the following example with a list and a button wrapped in a HStack that opens up a sheet:
struct ContentView: View {
#State var text: String = ""
#State var showSheet = false
var body: some View {
NavigationView {
List {
HStack {
button
}
Text("Hello World")
}
.searchable(text: $text)
}
}
var button: some View {
Button("Press", action: { showSheet = true })
.sheet(isPresented: $showSheet) {
modalView
}
}
var modalView: some View {
NavigationView {
List {
Text("Test")
}
}
}
}
On press of the button, a modal is presented to the user. However, the searchable modifier gets passed to the modal, see this video.
Now if the HStack is removed, everything works fine:
List {
button
Text("Hello World")
}
In addition, everything works also fine if the modal is not a NavigationView:
var modalView: some View {
List {
Text("Test")
}
}
Does somebody know what the problem here might be or is it once again one of those weird SwiftUI bugs?
putting the sheet, outside of the button and the List, works for me. I think .sheet is not meant to be inside a List, especially where searchable is operating.
struct ContentView: View {
#State var text: String = ""
#State var showSheet = false
var body: some View {
NavigationView {
List {
HStack {
button
}
Text("Hello World")
}
.searchable(text: $text)
}
.sheet(isPresented: $showSheet) {
modalView
}
}
var button: some View {
Button("Press", action: { showSheet = true })
}
var modalView: some View {
NavigationView {
List {
Text("Test")
}
}
}
}
Another workaround is to use navigationBarHidden = true, but then you must live without the navigation bar in the sheet view.
var modalView: some View {
NavigationView {
List {
Text("Test")
}
.navigationBarHidden(true)
}
}
Btw, on iPadOS it helps to use .searchable(text: $text, placement: .sidebar)
I want to set navigation view be always black, even when list comes under it. Right now the navigation view becomes gray in this case. I want to change color of navigation view dynamically, that's why I used NavigationBarModifier, but as this is not connected to this question I deleted functions that do that. Here's the current code.
import SwiftUI
struct NavigationBarModifier: ViewModifier {
var backgroundColor: Binding<Color>
init(backgroundColor: Binding<Color>) {
self.backgroundColor = backgroundColor
}
func body(content: Content) -> some View {
ZStack{
content
VStack {
GeometryReader { geometry in
self.backgroundColor.wrappedValue
.frame(height: geometry.safeAreaInsets.top)
.edgesIgnoringSafeArea(.top)
Spacer()
}
}
}
}
}
extension View {
func navigationBarColor(_ bgColor: Binding<Color>) -> some View {
self.modifier(NavigationBarModifier(backgroundColor: bgColor))
}
}
struct ContentView: View {
#State private var bgColor: Color = .black
var body: some View {
NavigationView {
List {
Button {
} label: {
Text("Button")
}
Button {
} label: {
Text("Button")
}
Button {
} label: {
Text("Button")
}
} .navigationBarColor(self.$bgColor)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
Here's how it looks now:
This is default behavior of navigation bar (inline display mode for List), you can disable navigation bar to get rid of it
NavigationView {
List {
Button {
} label: {
Text("Button")
}
Button {
} label: {
Text("Button")
}
Button {
} label: {
Text("Button")
}
}
.navigationBarHidden(true) // << here !!
.navigationBarColor(self.$bgColor)
}
I have a view that can be shown either as a modal, or simply pushed onto a navigation stack. When it's pushed, it has the back button in the top left, and when it's shown as a modal, I want to add a close button (many of my testers were not easily able to figure out that they could slide down the modal and really expected an explicit close button).
Now, I have multiple problems.
How do I figure out if a View is shown modally or not? Or alternatively, if it's not the first view on a navigation stack? In UIKit there are multiple ways to easily do this. Adding a presentationMode #Environment variable doesn't help, because its isPresented value is also true for pushed screens. I could of course pass in a isModal variable myself but it seems weird that's the only way?
How do I conditionally add a leading navigationBarItem? The problem is that if you give nil, even the default back button is hidden.
Code to copy and paste into Xcode and play around with:
import SwiftUI
struct ContentView: View {
#State private var showModal = false
var body: some View {
NavigationView {
VStack(spacing: 20) {
Button("Open modally") {
self.showModal = true
}
NavigationLink("Push", destination: DetailView(isModal: false))
}
.navigationBarTitle("Home")
}
.sheet(isPresented: $showModal) {
NavigationView {
DetailView(isModal: true)
}
}
}
}
struct DetailView: View {
#Environment(\.presentationMode) private var presentationMode
let isModal: Bool
var body: some View {
Text("Hello World")
.navigationBarTitle(Text("Detail"), displayMode: .inline)
.navigationBarItems(leading: closeButton, trailing: deleteButton)
}
private var closeButton: some View {
Button(action: { self.presentationMode.wrappedValue.dismiss() }) {
Image(systemName: "xmark")
.frame(height: 36)
}
}
private var deleteButton: some View {
Button(action: { print("DELETE") }) {
Image(systemName: "trash")
.frame(height: 36)
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
If I change closeButton to return an optional AnyView? and then return nil when isModal is false, I don't get a back button at all. I also can't call navigationBarItems twice, once with a leading and once with a trailing button, because the latter call overrides the first call. I'm kinda stuck here.
Okay, I managed it. It's not pretty and I am very much open to different suggestions, but it works 😅
import SwiftUI
extension View {
func eraseToAnyView() -> AnyView {
AnyView(self)
}
public func conditionalNavigationBarItems(_ condition: Bool, leading: AnyView, trailing: AnyView) -> some View {
Group {
if condition {
self.navigationBarItems(leading: leading, trailing: trailing)
} else {
self
}
}
}
}
struct ContentView: View {
#State private var showModal = false
var body: some View {
NavigationView {
VStack(spacing: 20) {
Button("Open modally") {
self.showModal = true
}
NavigationLink("Push", destination: DetailView(isModal: false))
}
.navigationBarTitle("Home")
}
.sheet(isPresented: $showModal) {
NavigationView {
DetailView(isModal: true)
}
}
}
}
struct DetailView: View {
#Environment(\.presentationMode) private var presentationMode
let isModal: Bool
var body: some View {
Text("Hello World")
.navigationBarTitle(Text("Detail"), displayMode: .inline)
.navigationBarItems(trailing: deleteButton)
.conditionalNavigationBarItems(isModal, leading: closeButton, trailing: deleteButton)
}
private var closeButton: AnyView {
Button(action: { self.presentationMode.wrappedValue.dismiss() }) {
Image(systemName: "xmark")
.frame(height: 36)
}.eraseToAnyView()
}
private var deleteButton: AnyView {
Button(action: { print("DELETE") }) {
Image(systemName: "trash")
.frame(height: 36)
}.eraseToAnyView()
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
I don't see any trouble, just add Dismiss button to your navigation bar. You only have to rearrange your View hierarchy and there is no need to pass any binding to your DetailView
import SwiftUI
struct DetailView: View {
var body: some View {
Text("Detail View")
}
}
struct ContentView: View {
#State var sheet = false
var body: some View {
NavigationView {
VStack(spacing: 20) {
Button("Open modally") {
self.sheet = true
}
NavigationLink("Push", destination: DetailView())
}.navigationBarTitle("Home")
}
.sheet(isPresented: $sheet) {
NavigationView {
DetailView().navigationBarTitle("Title").navigationBarItems(leading: Button(action: {
self.sheet.toggle()
}, label: {
Text("Dismiss")
}))
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
You still can dismiss it with swipe down, you can add some buttons (as part of DetailView declaration) ... etc.
When pushed, you have default back button, if shown modaly, you have dismiss
button indeed.
UPDATE (based od discussion)
.sheet(isPresented: $sheet) {
NavigationView {
GeometryReader { proxy in
DetailView().navigationBarTitle("Title")
.navigationBarItems(leading:
HStack {
Button(action: {
self.sheet.toggle()
}, label: {
Text("Dismiss").padding(.horizontal)
})
Color.clear
Button(action: {
}, label: {
Image(systemName: "trash")
.imageScale(.large)
.padding(.horizontal)
})
}.frame(width: proxy.size.width)
)
}
}
}
finally I suggest you to use
extension View {
#available(watchOS, unavailable)
public func navigationBarItems<L, T>(leading: L?, trailing: T) -> some View where L : View, T : View {
Group {
if leading != nil {
self.navigationBarItems(leading: leading!, trailing: trailing)
} else {
self.navigationBarItems(trailing: trailing)
}
}
}
}
Whenever we provide .navigationBarItems(leading: _anything_), ie anything, the standard back button has gone, so you have to provide your own back button conditionally.
The following approach works (tested with Xcode 11.2 / iOS 13.2)
.navigationBarItems(leading: Group {
if isModal {
closeButton
} else {
// custom back button here calling same dismiss
}
}, trailing: deleteButton)
Update: alternate approach might be as follows (tested in same)
var body: some View {
VStack {
if isModal {
Text("Hello")
.navigationBarItems(leading: closeButton, trailing: deleteButton)
} else {
Text("Hello")
.navigationBarItems(trailing: deleteButton)
}
}
.navigationBarTitle("Test", displayMode: .inline)
}
I couldn't find any reference about any ways to make a pop or a dismiss programmatically of my presented view with SwiftUI.
Seems to me that the only way is to use the already integrated slide dow action for the modal(and what/how if I want to disable this feature?), and the back button for the navigation stack.
Does anyone know a solution?
Do you know if this is a bug or it will stays like this?
This example uses the new environment var documented in the Beta 5 Release Notes, which was using a value property. It was changed in a later beta to use a wrappedValue property. This example is now current for the GM version. This exact same concept works to dismiss Modal views presented with the .sheet modifier.
import SwiftUI
struct DetailView: View {
#Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
var body: some View {
Button(
"Here is Detail View. Tap to go back.",
action: { self.presentationMode.wrappedValue.dismiss() }
)
}
}
struct RootView: View {
var body: some View {
VStack {
NavigationLink(destination: DetailView())
{ Text("I am Root. Tap for Detail View.") }
}
}
}
struct ContentView: View {
var body: some View {
NavigationView {
RootView()
}
}
}
SwiftUI Xcode Beta 5
First, declare the #Environment which has a dismiss method which you can use anywhere to dismiss the view.
import SwiftUI
struct GameView: View {
#Environment(\.presentationMode) var presentation
var body: some View {
Button("Done") {
self.presentation.wrappedValue.dismiss()
}
}
}
iOS 15+
Starting from iOS 15 we can use a new #Environment(\.dismiss):
struct SheetView: View {
#Environment(\.dismiss) var dismiss
var body: some View {
NavigationView {
Text("Sheet")
.toolbar {
Button("Done") {
dismiss()
}
}
}
}
}
(There's no more need to use presentationMode.wrappedValue.dismiss().)
Useful links:
DismissAction
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.
import SwiftUI
struct ContentView: View {
var body: some View {
NavigationView {
MasterView()
}
}
}
struct MasterView: View {
#State private 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
I recently created an open source project called swiftui-navigation-stack (https://github.com/biobeats/swiftui-navigation-stack) that contains the NavigationStackView, an alternative navigation stack for SwiftUI. It offers several features described in the readme of the repo. For example, you can easily push and pop views programmatically. I'll show you how to do that with a simple example:
First of all embed your hierarchy in a NavigationStackVew:
struct RootView: View {
var body: some View {
NavigationStackView {
View1()
}
}
}
NavigationStackView gives your hierarchy access to a useful environment object called NavigationStack. You can use it to, for instance, pop views programmatically as asked in the question above:
struct View1: View {
var body: some View {
ZStack {
Color.yellow.edgesIgnoringSafeArea(.all)
VStack {
Text("VIEW 1")
Spacer()
PushView(destination: View2()) {
Text("PUSH TO VIEW 2")
}
}
}
}
}
struct View2: View {
#EnvironmentObject var navStack: NavigationStack
var body: some View {
ZStack {
Color.green.edgesIgnoringSafeArea(.all)
VStack {
Text("VIEW 2")
Spacer()
Button(action: {
self.navStack.pop()
}, label: {
Text("PROGRAMMATICALLY POP TO VIEW 1")
})
}
}
}
}
In this example I use the PushView to trigger the push navigation with a tap. Then, in the View2 I use the environment object to programmatically come back.
Here is the complete example:
import SwiftUI
import NavigationStack
struct RootView: View {
var body: some View {
NavigationStackView {
View1()
}
}
}
struct View1: View {
var body: some View {
ZStack {
Color.yellow.edgesIgnoringSafeArea(.all)
VStack {
Text("VIEW 1")
Spacer()
PushView(destination: View2()) {
Text("PUSH TO VIEW 2")
}
}
}
}
}
struct View2: View {
#EnvironmentObject var navStack: NavigationStack
var body: some View {
ZStack {
Color.green.edgesIgnoringSafeArea(.all)
VStack {
Text("VIEW 2")
Spacer()
Button(action: {
self.navStack.pop()
}, label: {
Text("PROGRAMMATICALLY POP TO VIEW 1")
})
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
RootView()
}
}
the result is:
Alternatively, if you don't want to do it programatically from a button, you can emit from the view model whenever you need to pop.
Subscribe to a #Published that changes the value whenever the saving is done.
struct ContentView: View {
#ObservedObject var viewModel: ContentViewModel
#Environment(\.presentationMode) var presentationMode
init(viewModel: ContentViewModel) {
self.viewModel = viewModel
}
var body: some View {
Form {
TextField("Name", text: $viewModel.name)
.textContentType(.name)
}
.onAppear {
self.viewModel.cancellable = self.viewModel
.$saved
.sink(receiveValue: { saved in
guard saved else { return }
self.presentationMode.wrappedValue.dismiss()
}
)
}
}
}
class ContentViewModel: ObservableObject {
#Published var saved = false // This can store any value.
#Published var name = ""
var cancellable: AnyCancellable? // You can use a cancellable set if you have multiple observers.
func onSave() {
// Do the save.
// Emit the new value.
saved = true
}
}
Please check Following Code it's so simple.
FirstView
struct StartUpVC: View {
#State var selection: Int? = nil
var body: some View {
NavigationView{
NavigationLink(destination: LoginView().hiddenNavigationBarStyle(), tag: 1, selection: $selection) {
Button(action: {
print("Signup tapped")
self.selection = 1
}) {
HStack {
Spacer()
Text("Sign up")
Spacer()
}
}
}
}
}
SecondView
struct LoginView: View {
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView{
Button(action: {
print("Login tapped")
self.presentationMode.wrappedValue.dismiss()
}) {
HStack {
Image("Back")
.resizable()
.frame(width: 20, height: 20)
.padding(.leading, 20)
}
}
}
}
}
You can try using a custom view and a Transition.
Here's a custom modal.
struct ModalView<Content>: View where Content: View {
#Binding var isShowing: Bool
var content: () -> Content
var body: some View {
GeometryReader { geometry in
ZStack(alignment: .center) {
if (!self.isShowing) {
self.content()
}
if (self.isShowing) {
self.content()
.disabled(true)
.blur(radius: 3)
VStack {
Text("Modal")
}
.frame(width: geometry.size.width / 2,
height: geometry.size.height / 5)
.background(Color.secondary.colorInvert())
.foregroundColor(Color.primary)
.cornerRadius(20)
.transition(.moveAndFade) // associated transition to the modal view
}
}
}
}
}
I reused the Transition.moveAndFade from the Animation Views and Transition tutorial.
It is defined like this:
extension AnyTransition {
static var moveAndFade: AnyTransition {
let insertion = AnyTransition.move(edge: .trailing)
.combined(with: .opacity)
let removal = AnyTransition.scale()
.combined(with: .opacity)
return .asymmetric(insertion: insertion, removal: removal)
}
}
You can test it - in the simulator, not in the preview - like this:
struct ContentView: View {
#State var isShowingModal: Bool = false
func toggleModal() {
DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
withAnimation {
self.isShowingModal = true
}
DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
withAnimation {
self.isShowingModal = false
}
}
}
}
var body: some View {
ModalView(isShowing: $isShowingModal) {
NavigationView {
List(["1", "2", "3", "4", "5"].identified(by: \.self)) { row in
Text(row)
}.navigationBarTitle(Text("A List"), displayMode: .large)
}.onAppear { self.toggleModal() }
}
}
}
Thanks to that transition, you will see the modal sliding in from the trailing edge, and the it will zoom and fade out when it is dismissed.
The core concept of SwiftUI is to watch over the data flow.
You have to use a #State variable and mutate the value of this variable to control popping and dismissal.
struct MyView: View {
#State
var showsUp = false
var body: some View {
Button(action: { self.showsUp.toggle() }) {
Text("Pop")
}
.presentation(
showsUp ? Modal(
Button(action: { self.showsUp.toggle() }) {
Text("Dismiss")
}
) : nil
)
}
}
I experienced a compiler issue trying to call value on the presentationMode binding. Changing the property to wrappedValue fixed the issue for me. I'm assuming value -> wrappedValue is a language update. I think this note would be more appropriate as a comment on Chuck H's answer but don't have enough rep points to comment, I also suggested this change as and edit but my edit was rejected as being more appropriate as a comment or answer.
This will also dismiss the view
let scenes = UIApplication.shared.connectedScenes
let windowScene = scenes.first as? UIWindowScene
let window = windowScene?.windows.first
window?.rootViewController?.dismiss(animated: true, completion: {
print("dismissed")
})