Demonstration of whitespace problem
When I nest a NavigationView within a NavigationView, an enormous amount of whitespace separates the back button and the new navigation bar title. Is there something I'm doing wrong in terms of setting up my SwiftUI views?
import SwiftUI
struct Dashboard: View {
#EnvironmentObject var user: User
let courses = Course.exampleCourses()
var body: some View {
NavigationView {
List(courses) { course in
NavigationLink(destination: CourseView(course: course)) {
Text(course.name)
}
}.navigationBarTitle("Welcome, \(user.first)!")
}
}
}
import SwiftUI
struct CourseView: View {
// #ObservedObject allows us to update views whenever values in course change
#ObservedObject var course: Course
#EnvironmentObject var user: User
var body: some View {
NavigationView {
List {
NavigationLink(destination: WritingPromptView(prompt: "What is your course goal, \(user.first)?", explanationText: "This is the answer", textLocation: self.$course.goal)) {
Text("Course Goal")
}
NavigationLink(destination: NotepadView(parent: self.course)) {
Text("Notepad")
}
NavigationLink(destination: WritingPromptView(prompt: "<Reflection prompt goes here>", explanationText: "<How to reflect goes here>", textLocation: self.$course.reflection)) {
Text("Reflection")
}
}.navigationBarTitle(course.name)
}
}
}
It's a double NavigationBar. Just remove NavigationView from your CourseView. If you have Previews for CourseView, you will probably want to wrap it NavigationView there.
Related
I understand its new, but this seems like pretty basic functionality that is not here. When implementing a .searchable in the new iOS 15, it would seem that a NavigationLink does not work, at all.
Ideally, the searchable would produce a filtered list with a ForEach and for each item, a Nav Link could take you to another view based on your selection. The ForEach and list works and looks beautiful, it just wont take you anywhere.
Watching WWDC21, they talk an awful lot about .searchable, but very little demonstration/example is given..
Here is a simple example, with no ForEach loop, that shows it does not work at all.. Am I missing something?
Any insight appreciated:
import SwiftUI
struct ContentView: View {
#State private var term = ""
var body: some View {
NavigationView {
Text("Hello, world!")
.padding()
}
.searchable(text: $term) {
NavigationLink(destination: SecondView()) {
Text("Go to second view")
}
}
}
}
struct SecondView: View {
var body: some View {
Text("Goodbye!")
.padding()
}
}
NavigationLink must always be inside NavigationView, no matter what. If you want to put it outside, like inside .searchable, you should use programmatic navigation with isActive.
struct ContentView: View {
#State private var term = ""
#State private var isPresenting = false
var body: some View {
NavigationView {
/// NavigationView must only contain 1 view
VStack {
Text("Hello, world!")
.padding()
/// invisible NavigationLink
NavigationLink(destination: SecondView(), isActive: $isPresenting) { EmptyView()}
}
}
.searchable(text: $term) {
Button { isPresenting = true } label: {
Text("Go to second view")
}
}
}
}
struct SecondView: View {
var body: some View {
Text("Goodbye!")
.padding()
}
}
Result:
I have a List with ForEach using a NavigationLink that when tapped displays a detail view. The DetailsView includes a sheet to save the detail information into an array. After the save, the sheet is dismissed but an additional DetailsView is put on the navigation stack, so that I need to tap the back link twice to get back to the listing.
I'm likely doing something incorrect as I'm relatively new to swiftui, but can't determine what.
Three things of interest:
In the ListView, I use .navigationViewStyle(StackNavigationViewStyle()). When removed, the issue goes away but the iPad gets messy for the ListView.
I'm using insert(at: 0) to add data in my array because I want the most recent data at the top of the listing. If I use append instead, the issue does go away. Wanting the most recently saved item at the top of the list, I add a sort, however sorting causes the duplicate issue to reappear.
The issue only seems to occur when selecting the first item created in the list (the last in the array) and then saving a new item into the array.
steps:
click Tap Here First, then tap SAVE, enter a name then click Save.
click tab bar item Saved.
click on the list item from step 1 in the Saved Items listing (nav bar should show "< Saved Items").
click SAVE, enter another name then click Save. At this point, the duplicate view appears with "< Back" as the leading nav bar item, clicking it takes you to the original detail view, then clicking "< Saved Items" takes you to the list view.
What am I doing wrong or what should I be doing better?
xcode 12.4/iOS 14.1
Stripped down code to reproduce:
struct TestModel: Identifiable, Codable {
private(set) var id: UUID
var name: String
}
class AppData: ObservableObject {
#Published var testList = [TestModel]()
}
struct NewView: View {
var body: some View {
NavigationView {
NavigationLink(
destination: DetailView(item: TestModel(id: UUID(), name: ""))) {
Text("Tap here first")
}.navigationBarTitle("Main View", displayMode: .inline)
}.navigationViewStyle(StackNavigationViewStyle())
}
}
struct ListView: View {
#EnvironmentObject var appData: AppData
var body: some View {
NavigationView {
List {
ForEach(appData.testList) { item in
NavigationLink(destination: DetailView(item: item)) {
Text(item.name)
}
}
}
.navigationBarTitle("Saved Items", displayMode: .inline)
}
.navigationViewStyle(StackNavigationViewStyle()) // remove this and issue goes away, but iPad gets "messy".
}
}
struct DetailView: View {
#State private var isSaveShowing = false
#State var item: TestModel
var body: some View {
ScrollView(.vertical, showsIndicators: false) {
VStack(alignment: .center, spacing: 20) {
Text(item.name)
Button(action: {
isSaveShowing = true
}) {
Text("Save".uppercased())
}.sheet(isPresented: $isSaveShowing) {
SaveView(currentItem: item)
}
}
}
}
}
struct SaveView: View {
var currentItem: TestModel
#State private var name = ""
#EnvironmentObject var appData: AppData
#Environment(\.presentationMode) var presentationMode
var body: some View {
NavigationView {
Form {
Section(header: Text("Enter Name ".uppercased())
) {
TextField("Name (required)", text: $name)
}
}
.navigationBarItems(
trailing: Button(action: {
// appData.testList.append(TestModel(id: UUID(), name: name)) // using append instead of insert also resolves issue...
appData.testList.insert(TestModel(id: UUID(), name: name), at: 0)
presentationMode.wrappedValue.dismiss()
}) {
Text("Save")
}
)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
struct ContentView: View {
var appData = AppData()
var body: some View {
TabView {
NewView().tabItem {
Image(systemName: "rectangle.stack.badge.plus")
Text("Calculate")
}
ListView().tabItem {
Image(systemName: "tray.and.arrow.down")
Text("Saved")
}
}
.environmentObject(appData)
}
}
Apparently, this must have been a bug in SwiftUI.
Running the same code using Xcode 12.5 beta 3 with iOS 14.5 the issue no longer occurs.
I have a TabView with two tabs in a SwiftUI lifecycle app, one of them has complex view structure: NavigationView with a lot of sub-views inside, i.e.: NavigationLinks and their DestinationViews are spread on multiple levels down the view tree, each sub-view on its own is another view hierarchy with sheets and / or other DestinationViews. At some point inside this hierarchy, I want to reset the TabView to its original state which is displaying the first most view, so the user can restart their journey right at that state, as they were to open the app for the first time, so it's kinda impossible to track down something like isActive & isPresented bindings to pop-off or dismiss the views and sheets.
I thought of wrapping the TabView inside another view: RootView in an attempt to find an easy way to recreate that TabView from scratch or something like refreshing / resetting the TabView, but couldn't find a clew on how to do it.
Here's my code snippet:
#main
struct TestApp: App {
var body: some Scene {
WindowGroup {
RootView()
}
}
}
struct RootView: View {
var body: some View {
ContentView()
}
}
struct ContentView: View {
var body: some View {
TabView { // <-- I need to reset it to its original state
View1() // <---- this view has complex view hierarchy
.tabItem {
Text("Home")
}.tag(0)
View2()
.tabItem {
Text("Settings")
}.tag(1)
}
}
}
p.s. I'm not looking for "popping off the view to root view", because this can't be done when there are many active NavigationLink destinations where the user might open one of the sheets and start a new navigation journey inside the sheet.
****** UPDATE ******
I've created a new Environment value to hold a boolean that should indicate whether the TabView should reset or not, and I've tracked every isPresented and isActive state variables in every view and reset them once that environment value is set to true like this:
struct ResetTabView: EnvironmentKey {
static var defaultValue: Binding<ResetTabObservable> = .constant(ResetTabObservable())
}
extension EnvironmentValues {
var resetTabView: Binding<ResetTabObservable> {
get { self[ResetTabView.self] }
set { self[ResetTabView.self] = newValue }
}
}
class ResetTabObservable: ObservableObject {
#Published var newValue = false
}
in every view that will present a sheet or push a new view I added something like this:
struct View3: View {
#State var showSheet = false
#Environment(\.resetTabView) var reset
var body: some View {
Text("This is view 3")
Button(action: {
showSheet = true
}, label: {
Text("show view 4")
})
.sheet(isPresented: $showSheet) {
View4()
}
.onReceive(reset.$newValue.wrappedValue, perform: { val in
if val == true {
showSheet = false
}
})
}
}
and in the last view (which will reset the TabView) I toggle the Environment value like this:
struct View5: View {
#Environment(\.resetTabView) var reset
var body: some View {
VStack {
Text("This is view 5")
Button(action: {
reset.newValue.wrappedValue = true
}, label: {
Text("reset tab view")
})
}
}
}
This resulted in awkward dismissal for views:
What i do for this is i make all my presentation bindings be stored using #SceneStorage("key") (instead of #State) this way they not only respect state restoration ! but you can also access them throughout your app easily by using the same key. This post gives a good example of how this enables the switching from Tab to Sidebar view on iPad.
I used this in my apps so if i have a button or something that needs to unwind many presentations it can read on all of these values and reset them back to wanted value without needing to pass around a load of bindings.
I have an #EnvironmentObject called word (of type Word) whose identifier property I'm using for the label of a NavigationLink in SwiftUI. For the DetailView that is linked to the NavigationLink, all I have put is this:
struct DetailView: View {
#EnvironmentObject var word: Word
var body: some View {
VStack {
Text(word.identifier)
Button(action: {
self.word.identifier += "a"
}) {
Text("Click to add an 'a' to Word's identifier")
}
}
}
}
The ContentView that leads to this DetailView looks like this (I've simplified my actual code to isolate the problem).
struct ContentView: View {
#EnvironmentObject var word: Word
var body: some View {
NavigationView {
NavigationLink(destination: DetailView()) {
Text(word.identifier)
}
}
}
}
When I tap the button on the DetailView, I'd expect it to update the DetailView with a new word.identifier that has an extra "a" appended onto it. When I tap it, however, it takes me back to the ContentView, albeit with an updated word.identifier. I can't seem to find a way to stay on my DetailView when the word.identifier being used by the ContentView's NavigationLink is modified. Also, I am running Xcode 11.3.1 and am currently unable to update, so if this is has been patched, please let me know.
Here is workaround solution
struct DetailView: View {
#EnvironmentObject var word: Word
#State private var identifier: String = ""
var body: some View {
VStack {
Text(self.identifier)
Button(action: {
self.identifier += "a"
}) {
Text("Click to add an 'a' to Word's identifier")
}
}
.onAppear {
self.identifier = self.word.identifier
}
.onDisappear {
self.word.identifier = self.identifier
}
}
}
This works as expected on iOS 13.4, assuming Word is something like:
class Word : ObservableObject {
#Published var identifier = "foo"
}
As detailed here (on an iOS topic), the following code can be used to make a SwiftUI View dismiss itself:
#Environment(\.presentationMode) var presentationMode
// ...
presentationMode.wrappedValue.dismiss()
However, this approach doesn't work for a native (not Catalyst) macOS NavigationView setup (such as the below), where the selected view is displayed alongside the List.
Ideally, when any of these sub-views use the above, the list would go back to having nothing selected (like when it first launched); however, the dismiss function appears to do nothing: the view remains exactly the same.
Is this a bug, or expected macOS behaviour?
Is there another approach that can be used instead?
struct HelpView: View {
var body: some View {
NavigationView {
List {
NavigationLink(destination:
AboutAppView()
) {
Text("About this App")
}
NavigationLink(destination:
Text("Here’s a User Guide")
) {
Text("User Guide")
}
}
}
}
}
struct AboutAppView: View {
#Environment(\.presentationMode) var presentationMode
public var body: some View {
Button(action: {
self.dismissSelf()
}) {
Text("Dismiss Me!")
}
}
private func dismissSelf() {
presentationMode.wrappedValue.dismiss()
}
}
FYI: The real intent is for less direct scenarios (such as triggering from an Alert upon completion of a task); the button setup here is just for simplicity.
The solution here is simple. Do not use Navigation View where you need to dismiss the view.
Check the example given by Apple https://developer.apple.com/tutorials/swiftui/creating-a-macos-app
If you need dismissable view, there is 2 way.
Create a new modal window (This is more complicated)
Use sheet.
Following is implimenation fo sheet in macOS with SwiftUI
struct HelpView: View {
#State private var showModal = false
var body: some View {
NavigationView {
List {
NavigationLink(destination:
VStack {
Button("About"){ self.showModal.toggle() }
Text("Here’s a User Guide")
}
) {
Text("User Guide")
}
}
}
.sheet(isPresented: $showModal) {
AboutAppView(showModal: self.$showModal)
}
}
}
struct AboutAppView: View {
#Binding var showModal: Bool
public var body: some View {
Button(action: {
self.showModal.toggle()
}) {
Text("Dismiss Me!")
}
}
}
There is also a 3rd option to use ZStack to create a Modal Card in RootView and change opacity to show and hide with dynamic data.