Add NavigationStack case study

Author: ole

ViewLifecycle.xcodeproj/project.pbxproj

@@ -17,6 +17,7 @@
 		5D305D2A293266D000E42700 /* CaseStudyTabView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D305D29293266D000E42700 /* CaseStudyTabView.swift */; };
 		5D60F905293FA5F400AE0726 /* CaseStudies.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D60F904293FA5F400AE0726 /* CaseStudies.swift */; };
 		5D60F907293FA8D400AE0726 /* CaseStudyIfElse.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D60F906293FA8D400AE0726 /* CaseStudyIfElse.swift */; };
+		5D60F93F293FBBE800AE0726 /* CaseStudyNavigationStack.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D60F93E293FBBE800AE0726 /* CaseStudyNavigationStack.swift */; };
 		5D6C3F6C2908541100A0C864 /* App.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D6C3F6B2908541100A0C864 /* App.swift */; };
 		5D6C3F6E2908541100A0C864 /* RootView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 5D6C3F6D2908541100A0C864 /* RootView.swift */; };
 		5D6C3F702908541200A0C864 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 5D6C3F6F2908541200A0C864 /* Assets.xcassets */; };
@@ -34,6 +35,7 @@
 		5D305D29293266D000E42700 /* CaseStudyTabView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CaseStudyTabView.swift; sourceTree = "<group>"; };
 		5D60F904293FA5F400AE0726 /* CaseStudies.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CaseStudies.swift; sourceTree = "<group>"; };
 		5D60F906293FA8D400AE0726 /* CaseStudyIfElse.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CaseStudyIfElse.swift; sourceTree = "<group>"; };
+		5D60F93E293FBBE800AE0726 /* CaseStudyNavigationStack.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CaseStudyNavigationStack.swift; sourceTree = "<group>"; };
 		5D6C3F682908541100A0C864 /* ViewLifecycle.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = ViewLifecycle.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		5D6C3F6B2908541100A0C864 /* App.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = App.swift; sourceTree = "<group>"; };
 		5D6C3F6D2908541100A0C864 /* RootView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RootView.swift; sourceTree = "<group>"; };
@@ -77,6 +79,7 @@
 				5D60F906293FA8D400AE0726 /* CaseStudyIfElse.swift */,
 				5D0520B82934E6130080E4C0 /* CaseStudyLazyVGrid.swift */,
 				5D305D232932547F00E42700 /* CaseStudyList.swift */,
+				5D60F93E293FBBE800AE0726 /* CaseStudyNavigationStack.swift */,
 				5D305D25293260BE00E42700 /* CaseStudyScrollViewVStackForEach.swift */,
 				5D305D212932444500E42700 /* CaseStudyScrollView.swift */,
 				5D0520B62934DC330080E4C0 /* CaseStudyStaticList.swift */,
@@ -174,6 +177,7 @@
 				5D305D2A293266D000E42700 /* CaseStudyTabView.swift in Sources */,
 				5D305D28293260EC00E42700 /* SampleModel.swift in Sources */,
 				5D305D26293260BE00E42700 /* CaseStudyScrollViewVStackForEach.swift in Sources */,
+				5D60F93F293FBBE800AE0726 /* CaseStudyNavigationStack.swift in Sources */,
 				5D60F907293FA8D400AE0726 /* CaseStudyIfElse.swift in Sources */,
 				5D305D222932444500E42700 /* CaseStudyScrollView.swift in Sources */,
 				5D305D242932547F00E42700 /* CaseStudyList.swift in Sources */,

ViewLifecycle/CaseStudies.swift

@@ -15,28 +15,40 @@ extension CaseStudy {
         id: "ifElse",
         label: "if/else"
     )
+
     static let scrollView: Self = .init(
         id: "scrollView",
         label: "ScrollView with static content"
     )
+
     static let scrollViewVStackForEach: Self = .init(
         id: "scrollViewVStackForEach",
         label: "ScrollView > VStack > ForEach",
         description: "A VStack with dynamic content, embedded in a ScrollView"
     )
+
     static let staticList: Self = .init(
         id: "staticList",
         label: "List with static content"
     )
+
     static let list: Self = .init(
         id: "list",
         label: "List with dynamic content",
         description: "List recycles views during scrolling, so onAppear gets called often. But List preserves the State for all list items."
     )
+
     static let lazyVGrid: Self = .init(
         id: "lazyVGrid",
         label: "LazyVGrid"
     )
+
+    static let navigationStack: Self = .init(
+        id: "navigationStack",
+        label: "NavigationStack",
+        description: "A NavigationStack with infinite levels of drill-down."
+    )
+
     static let tabView: Self = .init(
         id: "tabView",
         label: "TabView",
@@ -70,15 +82,16 @@ let categories: [Category] = [
     ),
     Category(
         id: "lazy",
-        label: "Lazy Containers",
+        label: "Lazy containers",
         elements: [
             .lazyVGrid,
         ]
     ),
     Category(
-        id: "tabView",
-        label: "TabView",
+        id: "navigation",
+        label: "Navigation containers",
         elements: [
+            .navigationStack,
             .tabView,
         ]
     ),

ViewLifecycle/CaseStudyNavigationStack.swift

@@ -0,0 +1,43 @@
+import SwiftUI
+
+struct CaseStudyNavigationStack: View {
+    var body: some View {
+        NavigationStack {
+            Content(level: 1)
+        }
+    }
+
+    struct Content: View {
+        var level: Int
+
+        var body: some View {
+            List {
+                Section {
+                    NavigationLink {
+                        Content(level: level + 1)
+                    } label: {
+                        LifecycleMonitor(label: "Level \(level)")
+                    }
+                } footer: {
+                    if level == 1 {
+                        Text(explanation)
+                            .font(.callout)
+                            .frame(maxWidth: .infinity, alignment: .leading)
+                    }
+                }
+            }
+            .listStyle(.plain)
+            .navigationTitle(level == 1 ? "NavigationStack" : "Level \(level)")
+        }
+
+        private var explanation: LocalizedStringKey {
+            "Navigation views keep the state of content views on the navigation stack alive. `onAppear` and `onDisappear` get called as you navigate. Popping a view off the stack ends the view's lifetime, destroying its state."
+        }
+    }
+}
+
+struct CaseStudyNavigationStack_Previews: PreviewProvider {
+    static var previews: some View {
+        CaseStudyNavigationStack()
+    }
+}

ViewLifecycle/RootView.swift

@@ -63,6 +63,8 @@ struct MainContent: View {
             CaseStudyList()
         case .lazyVGrid:
             CaseStudyLazyVGrid()
+        case .navigationStack:
+            CaseStudyNavigationStack()
         case .tabView:
             CaseStudyTabView()
         default: