Render ProgressView and Toggle

Demo/App.swiftpm/Sources/ContentView.swift

@@ -34,6 +34,7 @@ enum GalleryScreen: String, CaseIterable, Identifiable {
     case observation
     case state
     case modifiers
+    case controls
 
     var id: String { rawValue }
 
@@ -49,6 +50,7 @@ enum GalleryScreen: String, CaseIterable, Identifiable {
         case .observation: return "Observation"
         case .state: return "State"
         case .modifiers: return "Modifiers"
+        case .controls: return "Controls"
         }
     }
 
@@ -64,6 +66,7 @@ enum GalleryScreen: String, CaseIterable, Identifiable {
         case .observation: return AnyView(ObservationScreen())
         case .state: return AnyView(StateScreen())
         case .modifiers: return AnyView(ModifierScreen())
+        case .controls: return AnyView(ControlsScreen())
         }
     }
 }

Demo/App.swiftpm/Sources/ControlsScreen.swift

@@ -0,0 +1,35 @@
+#if canImport(AndroidSwiftUI)
+import AndroidSwiftUI
+#else
+import SwiftUI
+#endif
+
+/// Form controls and their state bindings.
+struct ControlsScreen: View {
+
+    @State
+    private var isOn = false
+
+    @State
+    private var progress = 0.25
+
+    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
+                }
+            }
+        }
+    }
+}

Demo/app/src/main/java/com/pureswift/swiftandroid/CompoundButtonOnCheckedChangeListener.kt

@@ -0,0 +1,8 @@
+package com.pureswift.swiftandroid
+
+import android.widget.CompoundButton
+
+class CompoundButtonOnCheckedChangeListener(val action: SwiftObject): CompoundButton.OnCheckedChangeListener {
+
+    external override fun onCheckedChanged(button: CompoundButton, isChecked: Boolean)
+}

Demo/build-swift.sh

@@ -8,9 +8,10 @@ xcrun --toolchain swift swift build -c $SWIFT_COMPILATION_MODE \
     --toolchain $XCTOOLCHAIN \
     --package-path $SWIFT_PACKAGE_SRC
 
-# Copy compiled Swift package
+# Copy compiled Swift package, along with the shared libraries it links against
+# (`libSwiftJava.so` is loaded at runtime and the app fails to start without it)
 mkdir -p $SRC_ROOT/app/src/main/jniLibs/$ANDROID_ARCH/
-cp -rf $SWIFT_PACKAGE_SRC/.build/$SWIFT_TARGET_NAME/debug/libSwiftAndroidApp.so \
+cp -rf $SWIFT_PACKAGE_SRC/.build/$SWIFT_TARGET_NAME/debug/*.so \
     $SRC_ROOT/app/src/main/jniLibs/$ANDROID_ARCH/
 
 # Build locally for preview

Sources/AndroidSwiftUI/AndroidProgressView.swift

@@ -0,0 +1,68 @@
+//
+//  AndroidProgressView.swift
+//  AndroidSwiftUI
+//
+//  Created by Alsey Coleman Miller on 7/22/26.
+//
+
+import AndroidKit
+
+/// The scale determinate progress is reported on, since `ProgressBar` works in whole steps
+/// while `ProgressView` reports a fraction between zero and one.
+private let progressScale: Int32 = 10_000
+
+extension _FractionalProgressView: AndroidPrimitive {
+
+    var renderedBody: AnyView {
+        AnyView(AndroidProgressBar(fractionCompleted: fractionCompleted))
+    }
+}
+
+extension _IndeterminateProgressView: AndroidPrimitive {
+
+    var renderedBody: AnyView {
+        AnyView(AndroidProgressBar(fractionCompleted: nil))
+    }
+}
+
+/// Native progress bar, shown as a horizontal track when the progress is known and as the
+/// platform's indeterminate spinner otherwise.
+struct AndroidProgressBar {
+
+    let fractionCompleted: Double?
+}
+
+extension AndroidProgressBar: AndroidViewRepresentable {
+
+    typealias Coordinator = Void
+
+    func makeAndroidView(context: Self.Context) -> AndroidWidget.ProgressBar {
+        // the horizontal track is only selectable through a style attribute, so the
+        // determinate and indeterminate bars are distinct widgets rather than one widget
+        // toggling `setIndeterminate`
+        let style = fractionCompleted == nil
+            ? try! JavaClass<AndroidR.R.attr>().progressBarStyle
+            : try! JavaClass<AndroidR.R.attr>().progressBarStyleHorizontal
+        let view = AndroidWidget.ProgressBar(context.androidContext, nil, style)
+        view.setMax(progressScale)
+        updateView(view)
+        return view
+    }
+
+    func updateAndroidView(_ view: AndroidWidget.ProgressBar, context: Self.Context) {
+        updateView(view)
+    }
+}
+
+private extension AndroidProgressBar {
+
+    func updateView(_ view: AndroidWidget.ProgressBar) {
+        guard let fractionCompleted else {
+            view.setIndeterminate(true)
+            return
+        }
+        view.setIndeterminate(false)
+        let clamped = min(max(fractionCompleted, 0), 1)
+        view.setProgress(Int32((clamped * Double(progressScale)).rounded()))
+    }
+}

Sources/AndroidSwiftUI/AndroidToggle.swift

@@ -0,0 +1,66 @@
+//
+//  AndroidToggle.swift
+//  AndroidSwiftUI
+//
+//  Created by Alsey Coleman Miller on 7/22/26.
+//
+
+import AndroidKit
+
+/// Renders a toggle as the platform's Material switch.
+///
+/// `Toggle` reads `EnvironmentValues.toggleStyle` whether or not its body is used, and the
+/// key traps unless a renderer supplies a default, so this is registered in
+/// `EnvironmentValues.defaultEnvironment`.
+struct DefaultToggleStyle: ToggleStyle {
+
+    typealias Body = AndroidSwitch
+
+    func makeBody(configuration: ToggleStyleConfiguration) -> AndroidSwitch {
+        AndroidSwitch(isOn: configuration.$isOn, label: configuration.label)
+    }
+}
+
+/// Material switch bound to a `Bool`, labelled by the toggle's own label.
+struct AndroidSwitch {
+
+    @Binding
+    var isOn: Bool
+
+    let label: AnyView
+}
+
+extension AndroidSwitch: AndroidViewRepresentable {
+
+    typealias Coordinator = Void
+
+    func makeAndroidView(context: Self.Context) -> AndroidMaterial.MaterialSwitch {
+        let view = MaterialSwitch(context.androidContext)
+        let listener = CompoundButtonOnCheckedChangeListener { isChecked in
+            // only write back on a real change, so the binding isn't touched when the
+            // reconciler sets the checked state during an update
+            guard isChecked != self.isOn else { return }
+            self.isOn = isChecked
+        }
+        view.setOnCheckedChangeListener(listener.as(AndroidWidget.CompoundButton.OnCheckedChangeListener.self))
+        updateView(view)
+        return view
+    }
+
+    func updateAndroidView(_ view: AndroidMaterial.MaterialSwitch, context: Self.Context) {
+        updateView(view)
+    }
+}
+
+private extension AndroidSwitch {
+
+    func updateView(_ view: AndroidMaterial.MaterialSwitch) {
+        if view.isChecked() != isOn {
+            view.setChecked(isOn)
+        }
+        if let text = mapAnyView(label, transform: { (text: Text) in text }),
+           let textView = view.as(AndroidWidget.TextView.self) {
+            text.updateTextView(textView)
+        }
+    }
+}

Sources/AndroidSwiftUI/OnCheckedChangeListener.swift

@@ -0,0 +1,45 @@
+//
+//  OnCheckedChangeListener.swift
+//  AndroidSwiftUI
+//
+//  Created by Alsey Coleman Miller on 7/22/26.
+//
+
+import Foundation
+import AndroidKit
+
+@JavaClass("com.pureswift.swiftandroid.CompoundButtonOnCheckedChangeListener", extends: AndroidWidget.CompoundButton.OnCheckedChangeListener.self)
+open class CompoundButtonOnCheckedChangeListener: JavaObject {
+
+    public typealias Action = (Bool) -> ()
+
+    @JavaMethod
+    @_nonoverride public convenience init(action: SwiftObject?, environment: JNIEnvironment? = nil)
+
+    @JavaMethod
+    public func getAction() -> SwiftObject?
+}
+
+@JavaImplementation("com.pureswift.swiftandroid.CompoundButtonOnCheckedChangeListener")
+extension CompoundButtonOnCheckedChangeListener {
+
+    @JavaMethod
+    func onCheckedChanged(_ isChecked: Bool) {
+        // drain queue, matching `ViewOnClickListener`
+        RunLoop.main.run(until: Date() + 0.01)
+        action(isChecked)
+        RunLoop.main.run(until: Date() + 0.01)
+    }
+}
+
+public extension CompoundButtonOnCheckedChangeListener {
+
+    convenience init(action: @escaping (Bool) -> (), environment: JNIEnvironment? = nil) {
+        let object = SwiftObject(action, environment: environment)
+        self.init(action: object, environment: environment)
+    }
+
+    var action: ((Bool) -> ()) {
+        getAction()!.valueObject().value as! Action
+    }
+}

Sources/AndroidSwiftUI/TokamakCore/Environment/EnvironmentValues.swift

@@ -117,6 +117,9 @@ internal extension EnvironmentValues {
     static var defaultEnvironment: Self {
         var environment = EnvironmentValues()
         environment[_ColorSchemeKey.self] = .light
+        // control style keys trap unless the renderer supplies a default, and are read
+        // whenever a control is in the view tree — not only when its body is evaluated
+        environment[_ToggleStyleKey.self] = _AnyToggleStyle(DefaultToggleStyle())
         return environment
     }
 }