Building a great Mac app with SwiftUI

At a glance

Project structure

Source bundle/
├── Session1/
│   ├── Part1-End/
│   │   └── GardenApp/
│   │       ├── GardenApp.swift
│   │       ├── Navigation/
│   │       │   ├── ContentView.swift
│   │       │   └── GardenDetail.swift
│   │       └── Model/
│   │           └── Store.swift
│   └── Part1-Start/
│       └── GardenApp/
│           ├── GardenApp.swift
│           ├── Navigation/
│           │   ├── ContentView.swift
│           │   └── GardenDetail.swift
│           └── Model/
│               └── Store.swift
└── Session2/
    ├── Part2-End/
    │   └── GardenApp/
    │       ├── GardenApp.swift
    │       └── Views/
    │           └── SettingsView.swift
    └── Part2-Start/
        └── GardenApp/
            ├── GardenApp.swift
            └── Views/
                └── SettingsView.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 15 project/configuration file(s) and 95 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["Session1"]
    V2["Session2"]
    Boundary["SwiftUI APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

Session1/Part1-End/GardenApp/GardenApp.swift:10 — architecture anchor

@main
struct GardenApp: App {

    @StateObject private var store = Store()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(store)
        }
        .commands {
            SidebarCommands()
            PlantCommands()
        }
    }
}

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
    GardenApp *-- Store : store
    ContentView o-- Store : store
    ContentView o-- ID : selectedGardenID
    Sidebar o-- Store : store

Ownership evidence

Session1/Part1-End/GardenApp/GardenApp.swift:13 — stored dependency or nearest verified ownership anchor

@main
struct GardenApp: App {
    // ...
    @StateObject private var store = Store()
    // ...
}

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

Session2/Part2-End/GardenApp/Model/Plant+ImportImage.swift:28 — representative execution boundary

                        DispatchQueue.main.async {
                            completion(nil)
                        }

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

Session1/Part1-End/GardenApp/GardenApp.swift:11 — representative type boundary

@main
struct GardenApp: App {
    // ...
    @StateObject private var store = Store()
    // ...
}

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

Access control

Reference code

Session1/Part1-End/GardenApp/GardenApp.swift:13 — representative boundary

@main
struct GardenApp: App {
    // ...
    @StateObject private var store = Store()
    // ...
}

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: GardenApp; Store: Store; View: ContentView, SettingsView.
• Protocols: no local protocol declaration in the scanned source.
• Methods: no representative method name extracted from the architectural files.
• Files: Session1/Part1-End/GardenApp/GardenApp.swift, Session1/Part1-Start/GardenApp/GardenApp.swift, Session2/Part2-End/GardenApp/GardenApp.swift, Session2/Part2-Start/GardenApp/GardenApp.swift, Session1/Part1-End/GardenApp/Navigation/ContentView.swift, Session2/Part2-End/GardenApp/Views/SettingsView.swift.

Architecture takeaways

• GardenApp is the main source-visible entry or composition anchor for this sample.
• Framework work reaches SwiftUI, UniformTypeIdentifiers, AppKit 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