Adopting Picture in Picture Playback in tvOS

At a glance

Project structure

Source bundle/
├── PictureInPictureSample/
│   ├── AppDelegate.swift
│   ├── ButtonGridView.swift
│   ├── CustomPlayerControlsView.swift
│   ├── CustomPlayerViewController.swift
│   ├── ViewController.swift
│   ├── PlaybackItem.swift
│   ├── Info-iOS.plist
│   └── Info-tvOS.plist
├── Configuration/
│   └── SampleCode.xcconfig
└── PictureInPictureSample.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

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 13 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["ViewController"]
    N3["AVKit APIs"]
    N1 --> N2
    N2 --> N3

Reference code

PictureInPictureSample/AppDelegate.swift:11 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        window = UIWindow(frame: UIScreen.main.bounds)
        window?.rootViewController = ViewController()
        window?.makeKeyAndVisible()

        // The app's AVAudioSession must be a PiP-appropriate audio category, such as AVAudioSessionCategoryPlayback.
        do {
            try AVAudioSession.sharedInstance().setCategory(.playback, mode: .moviePlayback)
        } catch {
            print("Setting category to AVAudioSessionCategoryPlayback failed.")
        }

        return true
    }
}

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
    AppDelegate o-- UIWindow : window
    Button o-- IndexPath : indexPath
    Button o-- ButtonGridViewDelegate : delegate
    Button o-- Text : text

Ownership evidence

PictureInPictureSample/AppDelegate.swift:14 — stored dependency or nearest verified ownership anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    var window: UIWindow?
    // ...
}

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

PictureInPictureSample/CustomPlayerControlsView.swift:71 — representative execution boundary

        RunLoop.main.add(self.progressTimer, forMode: .default)

        let menuGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(menuGestureHandler(recognizer:)))
        menuGestureRecognizer.allowedPressTypes = [UIPress.PressType.menu].map { $0.rawValue as NSNumber }

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

PictureInPictureSample/ButtonGridView.swift:10 — representative type boundary

protocol ButtonGridViewDelegate: AnyObject {
    func buttonGrid(_ buttonGrid: ButtonGridView, titleForButtonAtIndexPath indexPath: IndexPath) -> String
    func buttonGrid(_ buttonGrid: ButtonGridView, didSelectItemAtIndexPath indexPath: IndexPath)
}

The source explicitly defines local protocol relationships: CustomPlayerViewController → CustomPlayerControlsViewDelegate, ViewController → CustomPlayerViewControllerDelegate, ViewController → ButtonGridViewDelegate.

Access control

Reference code

PictureInPictureSample/ButtonGridView.swift:101 — representative boundary

    @objc private func didSelectButton(button: Button) {
        delegate?.buttonGrid(self, didSelectItemAtIndexPath: button.indexPath)
    }

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

Naming conventions

• Types: Controller: CustomPlayerViewController, ViewController; Delegate: AppDelegate, ButtonGridViewDelegate, CustomPlayerControlsViewDelegate, CustomPlayerViewControllerDelegate; View: ButtonGridView, CustomPlayerControlsView.
• Protocols: ButtonGridViewDelegate, CustomPlayerControlsViewDelegate, CustomPlayerViewControllerDelegate.
• Methods: application, buttonGrid, didUpdateFocus, didSelectButton, controlsViewDidRequestStartPictureInPicture, controlsViewDidRequestStopPictureInPicture, controlsViewDidRequestControlsDismissal, controlsViewDidRequestPlayerDismissal.
• Files: PictureInPictureSample/AppDelegate.swift, PictureInPictureSample/ButtonGridView.swift, PictureInPictureSample/CustomPlayerControlsView.swift, PictureInPictureSample/CustomPlayerViewController.swift, PictureInPictureSample/ViewController.swift, PictureInPictureSample/PlaybackItem.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches UIKit, AVKit, AVFoundation 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.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation