Supporting Continuity Camera in your tvOS app

At a glance

Project structure

Source bundle/
├── App/
│   └── ContinuityCameraApp.swift
├── Observers/
│   ├── VideoEffectsObserver.swift
│   ├── CaptureDeviceNotificationObserver.swift
│   └── PreferredCameraObserver.swift
├── Views/
│   ├── ContentView.swift
│   ├── TimerView.swift
│   ├── CameraPreview.swift
│   └── CaptureButton.swift
├── Camera/
│   ├── CaptureManager.swift
│   └── CaptureType.swift
└── Media export/
    ├── VideoCapturer.swift
    └── AudioCapturer.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 5 project/configuration file(s) and 21 source declaration(s).

Overall architecture

flowchart LR
    N1["ContinuityCameraApp"]
    N2["ContentView"]
    N3["CaptureManager"]
    N4["CaptureDeviceNotificationObserver"]
    N5["AVFoundation / SwiftUI APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4
    N4 --> N5

Reference code

App/ContinuityCameraApp.swift:11 — architecture anchor

@main
struct ContinuityCaptureApp: App {
    // ...
    var captureManager = CaptureManager()
    // ...
}

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into AVKit.

Ownership and state

classDiagram
    ContinuityCaptureApp *-- CaptureManager : captureManager
    ContinuityCaptureApp *-- AudioCapturer : audioCapturer
    ContinuityCaptureApp *-- PhotoCapturer : photoCapturer
    ContinuityCaptureApp *-- VideoCapturer : videoCapturer

Ownership evidence

App/ContinuityCameraApp.swift:17 — stored dependency or nearest verified ownership anchor

@main
struct ContinuityCaptureApp: App {
    // ...
    var captureManager = CaptureManager()
    // ...
}

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Concurrency, scheduling, and thread safety

Evidence limit: actor isolation, async/await, or Task creation does not by itself prove background-thread execution; Sendable conformance alone does not prove thread-safe mutation.

@MainActor/MainActor.run, DispatchQueue.main, and RunLoop.main are reported as distinct isolation, queue, and event-loop mechanisms. A plain Task is kept separate from Task.detached; neither is labeled as a background thread.

Reference code

Camera/CaptureManager+Observers.swift:58 — representative execution boundary

        DispatchQueue.main.async {
            self.activeInput = nil
        }

State propagation, frameworks, and dependencies

Evidence limit: an import proves a source-level compilation dependency at the cited line; it does not prove runtime use, architectural adoption, or whether a Swift package is a direct application dependency.

receive(on:) describes downstream delivery scheduling, while subscribe(on:) describes upstream subscription/request/cancel scheduling. An import Combine alone establishes neither behavior nor a Store, reducer, Redux, or other application architecture.

Class and protocol design

App/ContinuityCameraApp.swift:12 — representative type boundary

@main
struct ContinuityCaptureApp: App {
    // ...
    var captureManager = CaptureManager()
    // ...
}

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

Camera/CaptureManager+ContinuityCamera.swift:17 — representative boundary

    public func activateDefaultContinuityCameraDevice() -> Bool {
        // ...
                                                       for: .video,
        // ...
    }

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Main application flow

sequenceDiagram
    actor User
    participant View as ContentView
    participant Manager as CaptureManager
    participant Capturer as Selected capturer
    participant Output as AVFoundation output
    User->>View: Connect device or press shutter
    View->>Manager: select camera / start session
    User->>View: Capture photo, video, or audio
    View->>Capturer: capture command
    Capturer->>Output: begin capture
    Output-->>Capturer: delegate completion
    Capturer-->>View: publish state or photo callback

Reference code

Views/ContentView.swift:210 — onShutterButton

    private func onShutterButton() {
        switch captureType {
            case .photo:
                photoCapturer.onPhotoCompletion = { image in
                    showScreenFlash = true
                    previewImage = image
                }
                photoCapturer.capture()
            case .video:
                toggleVideoCapture()
            case .audio:
                toggleAudioCapture()
        }
    }

Naming conventions

• Types: App: ContinuityCaptureApp; Manager: CaptureManager; Observer: CaptureDeviceNotificationObserver, CaptureDevicePropertyObserver, PreferredCameraObserver, VideoEffectsObserver; View: ContentView, PreviewLayerView, TimerView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: observeCamera, setCurrentState, captureTypeLabel, configureSessionForCaptureType, buildEffectIndicators, onShutterButton, toggleVideoCapture, toggleAudioCapture.
• Files: Observers/VideoEffectsObserver.swift, Views/ContentView.swift, Views/TimerView.swift, Camera/CaptureManager.swift, Observers/CaptureDeviceNotificationObserver.swift, Observers/PreferredCameraObserver.swift.

Architecture takeaways

• ContinuityCameraApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches AVFoundation, SwiftUI, Photos, AVFAudio through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation