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Case study for list of navigation links. (pointfreeco#6)
* Case study for list of navigation links. * renames * wip Co-authored-by: Stephen Celis <[email protected]>
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‎Examples/CaseStudies/06-NavigationLinks.swift

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@@ -13,7 +13,6 @@ struct OptionalNavigationLinks: View {
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NavigationLink(
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unwrapping: self.$viewModel.fact,
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destination: { $fact in
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let _ = print(fact)
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FactEditor(fact: $fact.description)
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.disabled(self.viewModel.isLoading)
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.foregroundColor(self.viewModel.isLoading ? .gray : nil)

‎Examples/CaseStudies/07-NavigationLinkList.swift

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import SwiftUI
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import SwiftUINavigation
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private let readMe = """
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This case study demonstrates how to model a list of navigation links. Tap a row to drill down \
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and edit a counter. Edit screen allows cancelling or saving the edits.
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The domain for a row in the list has its own ObservableObject and Route enum, and it uses the \
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library's NavigationLink initializer to drive navigation from the route enum.
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"""
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struct ListOfNavigationLinks: View {
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@ObservedObject var viewModel: ListOfNavigationLinksViewModel
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var body: some View {
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Form {
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Section {
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Text(readMe)
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}
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List {
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ForEach(self.viewModel.rows) { rowViewModel in
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RowView(viewModel: rowViewModel)
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}
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.onDelete(perform: self.viewModel.deleteButtonTapped(indexSet:))
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}
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}
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.navigationTitle("List of Links")
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.toolbar {
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ToolbarItem {
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Button("Add") {
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self.viewModel.addButtonTapped()
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}
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}
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}
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}
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}
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class ListOfNavigationLinksViewModel: ObservableObject {
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@Published var rows: [ListOfNavigationLinksRowViewModel]
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init(rows: [ListOfNavigationLinksRowViewModel] = []) {
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self.rows = rows
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}
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func addButtonTapped() {
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withAnimation {
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self.rows.append(.init())
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}
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}
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func deleteButtonTapped(indexSet: IndexSet) {
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self.rows.remove(atOffsets: indexSet)
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}
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}
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fileprivate struct RowView: View {
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@ObservedObject var viewModel: ListOfNavigationLinksRowViewModel
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var body: some View {
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NavigationLink(
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unwrapping: self.$viewModel.route,
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case: /ListOfNavigationLinksRowViewModel.Route.edit
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) { $counter in
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EditView(counter: $counter)
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.navigationBarBackButtonHidden(true)
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.toolbar {
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ToolbarItem(placement: .primaryAction) {
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Button("Save") { self.viewModel.saveButtonTapped(counter: counter) }
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}
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ToolbarItem(placement: .cancellationAction) {
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Button("Cancel") { self.viewModel.cancelButtonTapped() }
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}
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}
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} onNavigate: {
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self.viewModel.setEditNavigation(isActive: $0)
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} label: {
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Text("\(self.viewModel.counter)")
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}
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}
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}
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class ListOfNavigationLinksRowViewModel: Identifiable, ObservableObject {
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let id = UUID()
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@Published var counter: Int
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@Published var route: Route?
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enum Route {
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case edit(Int)
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}
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init(
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counter: Int = 0,
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route: Route? = nil
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) {
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self.counter = counter
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self.route = route
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}
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func setEditNavigation(isActive: Bool) {
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self.route = isActive ? .edit(self.counter) : nil
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}
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func saveButtonTapped(counter: Int) {
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self.counter = counter
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self.route = nil
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}
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func cancelButtonTapped() {
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self.route = nil
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}
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}
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fileprivate struct EditView: View {
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@Binding var counter: Int
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var body: some View {
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Form {
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Text("Count: \(self.counter)")
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Button("Increment") {
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self.counter += 1
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}
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Button("Decrement") {
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self.counter -= 1
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}
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}
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}
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}
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struct ListOfNavigationLinks_Previews: PreviewProvider {
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static var previews: some View {
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NavigationView {
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ListOfNavigationLinks(
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viewModel: .init(
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rows: [
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.init(counter: 0),
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.init(counter: 0),
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.init(counter: 0),
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.init(counter: 0),
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.init(counter: 0),
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]
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)
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)
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}
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}
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}

‎Examples/CaseStudies/07-Routing.swift renamed to ‎Examples/CaseStudies/08-Routing.swift

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‎Examples/CaseStudies/08-CustomComponents.swift renamed to ‎Examples/CaseStudies/09-CustomComponents.swift

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‎Examples/CaseStudies/RootView.swift

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@@ -35,6 +35,9 @@ struct RootView: View {
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NavigationLink("Optional navigation links") {
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OptionalNavigationLinks()
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}
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NavigationLink("List of navigation links") {
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ListOfNavigationLinks(viewModel: .init())
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}
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} header: {
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Text("Navigation links")
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}

‎Examples/Examples.xcodeproj/project.pbxproj

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@@ -46,8 +47,9 @@
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@@ -123,8 +125,9 @@
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