Creating a seamless multiview playback experience

At a glance

Project structure

Source bundle/
└── MultiviewPlaybackSampleApp/
    ├── MultiviewPlaybackSampleAppApp.swift
    ├── ViewModels/
    │   ├── MainViewModel.swift
    │   └── LayoutGridViewModel.swift
    ├── Views/
    │   ├── MainView.swift
    │   ├── GridView.swift
    │   ├── LayoutGridView.swift
    │   ├── LayoutView.swift
    │   ├── PlaybackControlsView.swift
    │   ├── PlayerView.swift
    │   └── PlayerViewController.swift
    └── Models/
        ├── Menu.swift
        └── PlayerState.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 18 source declaration(s).

Overall architecture

flowchart LR
    N1["MultiviewPlaybackSampleAppApp"]
    N2["MainView"]
    N3["LayoutGridViewModel"]
    N4["AVFoundation APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

MultiviewPlaybackSampleApp/MultiviewPlaybackSampleAppApp.swift:10 — architecture anchor

@main
struct MultiviewPlaybackSampleAppApp: App {
    let mainViewModel = MainViewModel.createViewModelWithMenu

    var body: some Scene {
        WindowGroup {
            MainView(viewModel: mainViewModel)
        }
    }
}

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 AVFoundation.

Ownership and state

classDiagram
    MainViewModel *-- Array : navigation
    MainViewModel o-- MenuItem : menuItem
    MainViewModel o-- MainViewModel : createViewModelWithMenu
    LayoutGridViewModel o-- MenuItem : selectedItem

Ownership evidence

MultiviewPlaybackSampleApp/ViewModels/MainViewModel.swift:21 — stored dependency or nearest verified ownership anchor

@Observable
class MainViewModel {
    var navigation: [MenuNavigationRoute] = []
    // ...
}

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

MultiviewPlaybackSampleApp/Models/Menu.swift:11 — representative execution boundary

typealias DataModel = (Codable & Equatable & Sendable)

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

MultiviewPlaybackSampleApp/MultiviewPlaybackSampleAppApp.swift:11 — representative type boundary

@main
struct MultiviewPlaybackSampleAppApp: App {
    let mainViewModel = MainViewModel.createViewModelWithMenu
    // ...
}

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

Access control

Reference code

MultiviewPlaybackSampleApp/Models/PlayerState.swift:28 — representative boundary

@Observable
class PlayerState {
    // ...
    private let queue = DispatchQueue(label: "com.apple.AVFoundation.MultiviewPlaybackSampleApp.PlayerState.queue")
    // ...
}

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: App: MultiviewPlaybackSampleAppApp; Controller: PlayerViewController; View: GridView, LayoutGridView, LayoutView, MainView, PlaybackControlsView; ViewModel: LayoutGridViewModel, MainViewModel.
• Protocols: no local protocol declaration in the scanned source.
• Methods: showGridView, showLayoutView, updateValuesFromMenuItem, resetStates, invalidate, resetValues, createAllPlayers, updateLayoutGridValues.
• Files: MultiviewPlaybackSampleApp/MultiviewPlaybackSampleAppApp.swift, MultiviewPlaybackSampleApp/ViewModels/MainViewModel.swift, MultiviewPlaybackSampleApp/ViewModels/LayoutGridViewModel.swift, MultiviewPlaybackSampleApp/Views/MainView.swift, MultiviewPlaybackSampleApp/Models/Menu.swift, MultiviewPlaybackSampleApp/Views/GridView.swift.

Architecture takeaways

• MultiviewPlaybackSampleAppApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, AVFoundation, AVKit, AVRouting 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