Creating NFC Tags from Your iPhone

At a glance

Project structure

Source bundle/
├── FishTagCreator/
│   ├── AppDelegate.swift
│   ├── CouponViewController.swift
│   ├── MainViewController.swift
│   ├── MainViewController+DataSource.swift
│   ├── Base.lproj/
│   │   ├── LaunchScreen.storyboard
│   │   └── Main.storyboard
│   ├── FishTagCreator.entitlements
│   └── Info.plist
├── FishTagReader/
│   ├── AppDelegate.swift
│   ├── LoyaltyViewController.swift
│   └── ScanViewController.swift
└── Configuration/
    └── SampleCode.xcconfig

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 6 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["FishTagCreator"]
    V2["FishTagReader"]
    Boundary["CoreNFC APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

FishTagCreator/AppDelegate.swift:10 — architecture anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

}

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
    AppDelegate o-- UIWindow : window
    CouponViewController o-- NFCTagReaderSession : readerSession
    CouponViewController *-- String : couponCode
    MainViewController o-- NFCNDEFReaderSession : readerSession

Ownership evidence

FishTagCreator/AppDelegate.swift:13 — stored dependency or nearest verified ownership anchor

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

}

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

FishTagCreator/CouponViewController.swift:103 — representative execution boundary

        DispatchQueue.global().async {
            // ...
            let dataOffset: UInt8 = 4
            // ...
        }

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

FishTagCreator/AppDelegate.swift:11 — representative type boundary

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

}

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

Access control

Reference code

FishTagCreator/AppDelegate.swift:11 — representative boundary

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    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: CouponViewController, LoyaltyViewController, MainViewController, ScanViewController; Delegate: AppDelegate.
• Protocols: no local protocol declaration in the scanned source.
• Methods: application, createCoupon, write, writeCouponCode, tagReaderSessionDidBecomeActive, tagReaderSession, writeTag, createURLPayload.
• Files: FishTagCreator/AppDelegate.swift, FishTagReader/AppDelegate.swift, FishTagCreator/CouponViewController.swift, FishTagCreator/MainViewController.swift, FishTagReader/LoyaltyViewController.swift, FishTagReader/ScanViewController.swift.

Architecture takeaways

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