Interacting with nearby points of interest

At a glance

Project structure

Source bundle/
├── PointsOfInterest-UIKit/
│   ├── AppDelegate.swift
│   ├── BaseMapItemViewController.swift
│   ├── SearchResultsViewController.swift
│   ├── MapViewController.swift
│   ├── SceneDelegate.swift
│   └── SidebarViewController.swift
├── PointsOfInterest/
│   ├── PointsOfInterestApp.swift
│   ├── ContentView.swift
│   ├── MapModel.swift
│   ├── MapView.swift
│   └── NavigationModel.swift
└── Shared/
    └── MapSearchConfiguration.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 7 project/configuration file(s) and 29 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["PointsOfInterest-UIKit"]
    V2["PointsOfInterest"]
    Boundary["MapKit APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

PointsOfInterest-UIKit/AppDelegate.swift:10 — architecture anchor

@main
class AppDelegate: UIResponder, UIApplicationDelegate {

}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    Row *-- String : header
    Row o-- MKMapItem : mapItem
    Row o-- UICollectionViewDiffableDataSource : dataSource
    Row o-- UICollectionView : collectionView

Ownership evidence

PointsOfInterest-UIKit/BaseMapItemViewController.swift:18 — stored dependency or nearest verified ownership anchor

    struct Row: Hashable {
        var header: String?
        // ...
    }

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

PointsOfInterest-UIKit/MapViewController.swift:90 — representative execution boundary

            Task {
                // ...
                let request = MKMapItemRequest(mapFeatureAnnotation: annotation)
                // ...
            }

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

PointsOfInterest-UIKit/SearchResultsViewController.swift:178 — representative type boundary

@MainActor
protocol SearchResultsViewControllerDelegate: NSObjectProtocol {
    // ...
    func searchResultsViewController(_ viewController: SearchResultsViewController, didUpdate searchResults: [MKMapItem])
    // ...
}

The source explicitly defines local protocol relationships: SidebarViewController → SearchResultsViewControllerDelegate.

Access control

Reference code

PointsOfInterest-UIKit/BaseMapItemViewController.swift:40 — representative boundary

    private func configureViewHierarchy() {
        collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: createLayout())
        collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        view.addSubview(collectionView)
    }

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: PointsOfInterestApp; Controller: BaseMapItemViewController, MapViewController, SearchResultsViewController, SidebarViewController; DataSource: SearchDataSource; Delegate: AppDelegate, SceneDelegate, SearchResultsViewControllerDelegate; Model: MapModel, NavigationModel; Service: LocationService; View: ContentView, MapItemRowView, MapView, SearchCompletionItemView, SettingsView.
• Protocols: SearchResultsViewControllerDelegate.
• Methods: viewDidLoad, configureViewHierarchy, createLayout, configureDataSource, updateCollectionViewSnapshot, configureHeaderCell, configureResultCell, presentMapItemDetail.
• Files: PointsOfInterest-UIKit/AppDelegate.swift, PointsOfInterest/PointsOfInterestApp.swift, PointsOfInterest-UIKit/BaseMapItemViewController.swift, PointsOfInterest-UIKit/SearchResultsViewController.swift, Shared/MapSearchConfiguration.swift, PointsOfInterest-UIKit/MapViewController.swift.

Architecture takeaways

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