Integrating CarPlay with Your Navigation App

At a glance

Project structure

Source bundle/
├── CoastalRoads/
│   ├── App Lifecycle/
│   │   ├── AppDelegate.swift
│   │   ├── LoggerWindowSceneDelegate.swift
│   │   └── TemplateApplicationSceneDelegate.swift
│   ├── Controllers/
│   │   ├── MapViewController.swift
│   │   ├── Logger.swift
│   │   ├── LoggerViewController.swift
│   │   ├── TemplateManager.swift
│   │   └── TemplateManager+Extensions.swift
│   └── Views/
│       ├── MapScrollView.swift
│       └── CoastalTemplates.swift
└── CoastalRoads.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 6 project/configuration file(s) and 13 source declaration(s).

Overall architecture

flowchart LR
    N1["AppDelegate"]
    N2["LoggerViewController"]
    N3["TemplateManager"]
    N4["CarPlay APIs"]
    N1 --> N2
    N2 --> N3
    N3 --> N4

Reference code

CoastalRoads/App Lifecycle/AppDelegate.swift:10 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    // ...
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        MemoryLogger.shared.appendEvent("Application finished launching.")
        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 CarPlay.

Ownership and state

classDiagram
    MapViewController o-- MapScrollView : mapView
    MapViewController o-- MapViewActionProviding : mapViewActionProvider
    MapViewController *-- Bool : polylineVisible
    Event *-- Date : date

Ownership evidence

CoastalRoads/Controllers/MapViewController.swift:25 — stored dependency or nearest verified ownership anchor

class MapViewController: UIViewController {
    // ...
    var mapView: MapScrollView!
    // ...
}

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

CoastalRoads/Controllers/Logger.swift:64 — representative execution boundary

            DispatchQueue.main.async {
                delegate.loggerDidAppendEvent()
            }

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

CoastalRoads/Controllers/Logger.swift:31 — representative type boundary

protocol LoggerDelegate: AnyObject {

    /// The logger has received a new event.
    func loggerDidAppendEvent()
}

The source explicitly defines local protocol relationships: MemoryLogger → Logger, LoggerViewController → LoggerDelegate, TemplateManager → MapViewActionProviding.

Access control

Reference code

CoastalRoads/App Lifecycle/LoggerWindowSceneDelegate.swift:12 — representative boundary

class LoggerWindowSceneDelegate: NSObject, UIWindowSceneDelegate {
    // ...
    internal var window: UIWindow?
    // ...
}

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: LoggerViewController, MapViewController; Delegate: AppDelegate, LoggerDelegate, LoggerWindowSceneDelegate, TemplateApplicationSceneDelegate; Manager: TemplateManager; View: MapScrollView.
• Protocols: LoggerDelegate, MapViewActionProviding, Logger.
• Methods: application, applicationDidBecomeActive, applicationWillResignActive, applicationDidEnterBackground, applicationWillEnterForeground, setZoomInEnabled, setZoomOutEnabled, viewDidLoad.
• Files: CoastalRoads/App Lifecycle/AppDelegate.swift, CoastalRoads/Controllers/MapViewController.swift, CoastalRoads/Controllers/Logger.swift, CoastalRoads/Controllers/LoggerViewController.swift, CoastalRoads/Controllers/TemplateManager.swift, CoastalRoads/Views/MapScrollView.swift.

Architecture takeaways

• AppDelegate is the main source-visible entry or composition anchor for this sample.
• Framework work reaches CarPlay, UIKit, MapKit, SwiftUI 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