Sample CodeiOS, iPadOS, Mac CatalystReviewed 2026-07-21View on Apple Developer

ShazamKit Dance Finder with Managed Session

At a glance

Item Summary
Purpose Find a video of dance moves for a specific song by matching the audio to a custom catalog, and show a history of recognized songs.
App architecture A Swift sample with the source-visible chain ShazamKitDanceFinderAppContentViewNowPlayingViewModelResourcesProviderShazamKit APIs.
Main patterns Model-View-ViewModel, Delegate or data-source callbacks, Coordinator, SwiftUI environment injection, Publisher-backed observable state, Actor-isolated state
Project style 17 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

Project structure

Source bundle/
├── Shared Source/
│   ├── App/
│   │   ├── ShazamKitDanceFinderApp.swift
│   │   └── ContentView.swift
│   ├── Data/
│   │   ├── NowPlayingViewModel.swift
│   │   └── ResourcesProvider.swift
│   └── Views/
│       ├── DanceCompletionView.swift
│       ├── NowPlayingView.swift
│       ├── RecentDanceRowView.swift
│       └── VideoPlayerView.swift
├── Part 1 - Matching Audio/
│   └── ShazamKitDanceFinder/
│       ├── RecentDancesView.swift
│       └── Matcher.swift
├── Part 2 - Matching Audio with SHManagedSession/
│   └── ShazamKitDanceFinder/
│       └── RecentDancesView.swift
└── Part 3 - Final/
    └── ShazamKitDanceFinder/
        └── RecentDancesView.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 11 project/configuration file(s) and 31 source declaration(s).

Overall architecture

Reference code

Shared Source/App/ShazamKitDanceFinderApp.swift:10 — architecture anchor

@main
struct ShazamKitDanceFinderApp: App {
    // ...
}

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 ShazamKit.

Ownership and state

Ownership evidence

Part 1 - Matching Audio/ShazamKitDanceFinder/RecentDancesView.swift:20 — stored dependency or nearest verified ownership anchor

        static let emptyStateImageName: String = "EmptyStateIcon"
        static let emptyStateTextTitle: String = "No Dances Yet?"
        static let emptyStateTextSubtitle: String = "Find some music to start learning"
        static let deleteSwipeViewOpacity: Double = 0.5
        static let matchingStateTextTopPadding: CGFloat = 24
        static let matchingStateTextBottomPadding: CGFloat = 16
        static let progressViewScaleEffect: CGFloat = 1.1
Owner Object or state Relationship Mutation authority
RecentDancesView String (emptyStateImageName) owns value state Initialized by the owner; the binding is immutable
RecentDancesView String (emptyStateTextTitle) owns value state Initialized by the owner; the binding is immutable
RecentDancesView String (emptyStateTextSubtitle) owns value state Initialized by the owner; the binding is immutable
RecentDancesView Double (deleteSwipeViewOpacity) owns value state Initialized by the owner; the binding is immutable

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.

Class and protocol design

Shared Source/App/ShazamKitDanceFinderApp.swift:11 — representative type boundary

struct ShazamKitDanceFinderApp: App {
    // ...
}
Type Responsibility Depends on or conforms to
ShazamKitDanceFinderApp Application entry and top-level composition App
SceneHandler Handles callbacks or feature events ObservableObject
NowPlayingViewModel UI-facing state and feature coordination ObservableObject
RecentDancesView User-interface presentation and input forwarding View
RecentDancesView User-interface presentation and input forwarding View
RecentDancesView User-interface presentation and input forwarding View
DanceCompletionView User-interface presentation and input forwarding View
NowPlayingView User-interface presentation and input forwarding View
RecentDanceRowView User-interface presentation and input forwarding View
ContentView User-interface presentation and input forwarding View

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

Access control

Symbol Access Verified effect Likely rationale
session (Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:25) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
audioEngine (Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:26) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.
configureAudioEngine (Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:74) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: hide an implementation step that is not part of the collaboration surface.
isListEmpty (Part 1 - Matching Audio/ShazamKitDanceFinder/RecentDancesView.swift:41) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: keep state mutation or dependency lifetime inside the owning implementation.

Reference code

Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:25 — representative boundary

@MainActor final class Matcher: ObservableObject {
    // ...
    private let session: SHSession
    // ...
}

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

Logic Owning type or file Placement rationale
Application entry and top-level composition ShazamKitDanceFinderApp The source’s App suffix makes this role explicit.
Cross-object flow or session coordination Coordinator The source’s Coordinator suffix makes this role explicit.
Handles callbacks or feature events SceneHandler The source’s Handler suffix makes this role explicit.
Supplies a capability or framework resource ResourcesProvider The source’s Provider suffix makes this role explicit.
User-interface presentation and input forwarding ContentView, DanceCompletionView, NowPlayingView, RecentDanceRowView The source’s View suffix makes this role explicit.
UI-facing state and feature coordination NowPlayingViewModel The source’s ViewModel suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Model-View-ViewModel Shared Source/Data/NowPlayingViewModel.swift:11 Role-named view models keep UI-facing state or coordination outside view declarations.
Delegate or data-source callbacks Shared Source/Views/VideoPlayerView.swift:14 Callback protocols invert event delivery back into the sample’s owner.
Coordinator Shared Source/Views/VideoPlayerView.swift:14 A role-named coordinator centralizes cross-object flow.
SwiftUI environment injection Part 1 - Matching Audio/ShazamKitDanceFinder/RecentDancesView.swift:51 The environment supplies state or a capability without threading it through every initializer.
Publisher-backed observable state Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:19 Published properties notify observers while mutation remains with the state object.
Actor-isolated state Part 1 - Matching Audio/ShazamKitDanceFinder/Matcher.swift:16 Actor annotations make the concurrency ownership boundary explicit.

Naming conventions

  • Types: App: ShazamKitDanceFinderApp; Coordinator: Coordinator; Handler: SceneHandler; Provider: ResourcesProvider; View: ContentView, DanceCompletionView, NowPlayingView, RecentDanceRowView, RecentDancesView; ViewModel: NowPlayingViewModel.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: sceneChanged, setupPlayback, stopPlayback, addMediaItem, viewMovedToForeground, viewMovedToBackground, updateNowPlayingViewVisibility, hideNowPlayingView.
  • Files: Shared Source/App/ShazamKitDanceFinderApp.swift, Shared Source/Data/NowPlayingViewModel.swift, Part 1 - Matching Audio/ShazamKitDanceFinder/RecentDancesView.swift, Part 2 - Matching Audio with SHManagedSession/ShazamKitDanceFinder/RecentDancesView.swift, Part 3 - Final/ShazamKitDanceFinder/RecentDancesView.swift, Shared Source/Views/DanceCompletionView.swift.

Architecture takeaways

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

Source file Relevant symbols
Shared Source/App/ShazamKitDanceFinderApp.swift ShazamKitDanceFinderApp, SceneHandler, State
Shared Source/Data/NowPlayingViewModel.swift NowPlayingViewModel, Constants
Part 1 - Matching Audio/ShazamKitDanceFinder/RecentDancesView.swift NavigationPath, RecentDancesView, ViewConstants, RecentDancesView_Previews
Part 2 - Matching Audio with SHManagedSession/ShazamKitDanceFinder/RecentDancesView.swift NavigationPath, RecentDancesView, ViewConstants, RecentDancesView_Previews
Part 3 - Final/ShazamKitDanceFinder/RecentDancesView.swift NavigationPath, RecentDancesView, ViewConstants, RecentDancesView_Previews
Shared Source/Views/DanceCompletionView.swift DanceCompletionView, ViewConstants, DanceCompletionView_Previews
Shared Source/Views/NowPlayingView.swift NowPlayingView, ViewConstants, NowPlayingView_Previews
Shared Source/Views/RecentDanceRowView.swift RecentDanceRowView, ViewConstants, RecentDanceRowView_Previews
Shared Source/App/ContentView.swift ContentView, ContentView_Previews
Shared Source/Views/VideoPlayerView.swift VideoPlayerView, Coordinator