Render the gallery catalog in the desktop rig

Ports the gallery screens against the core and drives the desktop window from
ContentView, with a main-thread scheduler for async state.

Author: colemancda

Sources/SwiftUIDesktopDemo/DesktopDemo.swift

@@ -6,23 +6,11 @@
 //  pushed through the bridge into the rig's Compose window.
 //
 
+import Foundation
 import AndroidSwiftUICore
 import AndroidSwiftUIBridge
 import SwiftJava
 
-struct CounterDemo: View {
-
-    @State private var count = 0
-
-    var body: some View {
-        VStack(spacing: 12) {
-            Text("Count: \(count)")
-            Button("Increment") { count += 1 }
-            Toggle("Feature flag", isOn: .constant(true))
-        }
-    }
-}
-
 @JavaClass("com.pureswift.swiftui.desktop.SwiftRuntime")
 open class SwiftRuntime: JavaObject {
 }
@@ -33,7 +21,11 @@ extension SwiftRuntime {
     @JavaMethod
     func start(_ store: TreeStore?) {
         guard let store else { return }
-        let runtime = BridgeRuntime(root: CounterDemo(), store: store)
+        // marshal re-renders onto the main thread; async state (e.g. a List
+        // refresh Task) writes off-thread and JNI object creation must run here
+        let runtime = BridgeRuntime(root: ContentView(), store: store) { block in
+            DispatchQueue.main.async { block() }
+        }
         runtime.start()
     }
 }

Sources/SwiftUIDesktopDemo/Gallery/ButtonScreen.swift

@@ -0,0 +1,26 @@
+import AndroidSwiftUICore
+
+/// Button initializers and actions.
+struct ButtonScreen: View {
+
+    @State
+    private var tapCount = 0
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Text(verbatim: "Taps: \(tapCount)")
+            Button("Title initializer") {
+                tapCount += 1
+            }
+            Button(action: { tapCount += 1 }) {
+                Text("Label closure initializer")
+            }
+            Button(action: { tapCount += 1 }) {
+                Image("globe")
+            }
+            Button("Reset") {
+                tapCount = 0
+            }
+        }
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/ContentView.swift

@@ -0,0 +1,29 @@
+import AndroidSwiftUICore
+
+/// Gallery of playground screens, navigated with a `NavigationStack`. Each row
+/// pushes a feature screen; `List`-based navigation returns with lazy
+/// containers in the next step.
+struct ContentView: View {
+
+    var body: some View {
+        NavigationStack {
+            ScrollView {
+                VStack(spacing: 0) {
+                    NavigationLink("Text", destination: TextScreen())
+                    NavigationLink("Buttons", destination: ButtonScreen())
+                    NavigationLink("Stacks", destination: StacksScreen())
+                    NavigationLink("List", destination: ListScreen())
+                    NavigationLink("Grid", destination: GridScreen())
+                    NavigationLink("State", destination: StateScreen())
+                    NavigationLink("Controls", destination: ControlsScreen())
+                    NavigationLink("Modifiers", destination: ModifierScreen())
+                    NavigationLink("Observation", destination: ObservationScreen())
+                    NavigationLink("Navigation", destination: NavigationScreen())
+                    NavigationLink("Sheets", destination: SheetScreen())
+                    NavigationLink("Tabs", destination: TabScreen())
+                }
+            }
+            .navigationTitle("Gallery")
+        }
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/ControlsScreen.swift

@@ -0,0 +1,56 @@
+import AndroidSwiftUICore
+
+/// Form controls and their state bindings.
+struct ControlsScreen: View {
+
+    @State
+    private var isOn = false
+
+    @State
+    private var progress = 0.25
+
+    @State
+    private var sliderValue = 0.5
+
+    @State
+    private var name = ""
+
+    @State
+    private var fruit = "Apple"
+
+    var body: some View {
+        ScrollView {
+            VStack(spacing: 24) {
+                Text("Toggle")
+                Toggle("Enabled", isOn: $isOn)
+                Text(isOn ? "Toggle is on" : "Toggle is off")
+                Divider()
+                Text("Indeterminate progress")
+                ProgressView()
+                Divider()
+                Text("Determinate progress")
+                ProgressView(value: progress)
+                Text("\(Int(progress * 100))%")
+                Button("Advance") {
+                    progress = progress >= 1 ? 0 : progress + 0.25
+                }
+                Divider()
+                Text("Slider")
+                Slider(value: $sliderValue, in: 0...1)
+                Text("Value: \(Int(sliderValue * 100))%")
+                Divider()
+                Text("Text field")
+                TextField("Name", text: $name)
+                Text(name.isEmpty ? "Nothing typed yet" : "Hello, \(name)")
+                Divider()
+                Text("Picker")
+                Picker("Fruit", selection: $fruit) {
+                    Text("Apple").tag("Apple")
+                    Text("Banana").tag("Banana")
+                    Text("Cherry").tag("Cherry")
+                }
+                Text("Selected: \(fruit)")
+            }
+        }
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/GridScreen.swift

@@ -0,0 +1,37 @@
+import AndroidSwiftUICore
+
+/// Lazy grids.
+struct GridScreen: View {
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Text("Three fixed columns")
+            LazyVGrid(columns: [GridItem(.flexible()), GridItem(.flexible()), GridItem(.flexible())]) {
+                ForEach(1...9, id: \.self) { number in
+                    Text("\(number)")
+                        .padding()
+                        .background(Color.blue)
+                }
+            }
+            Divider()
+            Text("Adaptive columns")
+            LazyVGrid(columns: [GridItem(.adaptive(minimum: 80))]) {
+                ForEach(1...8, id: \.self) { number in
+                    Text("Item \(number)")
+                        .padding()
+                        .background(Color.orange)
+                }
+            }
+            Divider()
+            Text("Two rows, horizontal")
+            LazyHGrid(rows: [GridItem(.flexible()), GridItem(.flexible())]) {
+                ForEach(1...8, id: \.self) { number in
+                    Text("Cell \(number)")
+                        .padding()
+                        .background(Color.green)
+                }
+            }
+            .frame(height: 160)
+        }
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/ListScreen.swift

@@ -0,0 +1,32 @@
+import AndroidSwiftUICore
+
+/// A lazy list with pull to refresh. Rows are evaluated on demand, so the
+/// large-list variant scrolls without materializing every row up front.
+struct ListScreen: View {
+
+    @State
+    private var items = (1...30).map(ListItem.init)
+
+    var body: some View {
+        List(items) { item in
+            Text(item.title)
+        }
+        .refreshable {
+            await addItem()
+        }
+    }
+
+    private func addItem() async {
+        try? await Task.sleep(for: .seconds(1))
+        items.insert(ListItem(id: items.count + 1), at: 0)
+    }
+}
+
+struct ListItem: Identifiable {
+
+    let id: Int
+
+    var title: String {
+        "Row \(id)"
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/ModifierScreen.swift

@@ -0,0 +1,68 @@
+import AndroidSwiftUICore
+
+/// Layout and effect modifiers.
+struct ModifierScreen: View {
+
+    var body: some View {
+        ScrollView {
+            VStack(spacing: 24) {
+                ModifierSection(title: "Padding") {
+                    Text("Padded")
+                        .padding()
+                        .background(Color.blue)
+                }
+                ModifierSection(title: "Frame") {
+                    Text("Fixed 200x60")
+                        .frame(width: 200, height: 60)
+                        .background(Color.green)
+                }
+                ModifierSection(title: "Background") {
+                    Text("Colored background")
+                        .padding()
+                        .background(Color.orange)
+                }
+                ModifierSection(title: "Clip + corner radius") {
+                    Text("Rounded")
+                        .padding()
+                        .background(Color.purple)
+                        .cornerRadius(16)
+                }
+                ModifierSection(title: "Offset") {
+                    Text("Shifted")
+                        .offset(x: 30, y: 0)
+                        .background(Color.red)
+                }
+                ModifierSection(title: "Rotation") {
+                    Text("Rotated")
+                        .background(Color.yellow)
+                        .rotationEffect(.degrees(15))
+                }
+                ModifierSection(title: "Scale") {
+                    Text("Scaled")
+                        .background(Color.pink)
+                        .scaleEffect(1.5)
+                }
+            }
+        }
+    }
+}
+
+struct ModifierSection<Content: View>: View {
+
+    let title: String
+
+    let content: Content
+
+    init(title: String, @ViewBuilder content: () -> Content) {
+        self.title = title
+        self.content = content()
+    }
+
+    var body: some View {
+        VStack(spacing: 8) {
+            Text(title)
+            content
+            Divider()
+        }
+    }
+}

Sources/SwiftUIDesktopDemo/Gallery/NavigationScreen.swift

@@ -0,0 +1,73 @@
+import AndroidSwiftUICore
+
+/// Classic and value-based navigation, plus the dismiss environment action.
+struct NavigationScreen: View {
+
+    @Environment(\.dismiss)
+    private var dismiss
+
+    @State
+    private var showsAlert = false
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Button("Show alert") { showsAlert = true }
+            Text("Value-based navigation")
+            NavigationLink("Push value 1", value: 1)
+            NavigationLink(value: 2) {
+                Text("Push value 2")
+            }
+            Divider()
+            Text("Classic navigation")
+            NavigationLink("Push destination view", destination: ClassicDestination())
+            Divider()
+            Button("Pop with dismiss") {
+                dismiss()
+            }
+        }
+        .navigationDestination(for: Int.self) { value in
+            ValueDestination(value: value)
+        }
+        .alert("An alert", isPresented: $showsAlert, message: "This is an alert message.", buttons: [
+            AlertButton("Cancel", role: .cancel),
+            AlertButton("OK"),
+        ])
+        .navigationTitle("Navigation")
+    }
+}
+
+struct ValueDestination: View {
+
+    let value: Int
+
+    @Environment(\.dismiss)
+    private var dismiss
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Text(verbatim: "Destination for value \(value)")
+            if value < 3 {
+                NavigationLink("Push value \(value + 1)", value: value + 1)
+            }
+            Button("Pop with dismiss") {
+                dismiss()
+            }
+        }
+        .navigationTitle("Value \(value)")
+    }
+}
+
+struct ClassicDestination: View {
+
+    @Environment(\.dismiss)
+    private var dismiss
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Text("Classic destination")
+            Button("Pop with dismiss") {
+                dismiss()
+            }
+        }
+    }
+}