Building a document-based app using SwiftData
At a glance
| Item | Summary |
|---|---|
| Purpose | Code along with the WWDC presenter to transform an app with SwiftData. |
| App architecture | A Swift sample bundle with entry-bearing project variants End, Start, each leading to SwiftUI APIs. |
| Main patterns | Binding-based state propagation, Publisher-backed observable state, Actor-isolated state |
| Project style | 32 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries. |
Project structure
Source bundle/
├── End/
│ └── FlashCard/
│ ├── SwiftDataFlashCardSample.swift
│ └── Views/
│ ├── CardEditorView.swift
│ ├── CardContainerView.swift
│ ├── CardReaderView.swift
│ ├── ContentView.swift
│ └── FlashCardView.swift
└── Start/
└── FlashCard/
├── SwiftDataFlashCardSample.swift
└── Views/
├── CardEditorView.swift
├── CardContainerView.swift
├── CardReaderView.swift
├── ContentView.swift
└── FlashCardView.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 10 project/configuration file(s) and 34 source declaration(s).
Overall architecture
flowchart LR
Bundle["Sample bundle"]
V1["End"]
V2["Start"]
Boundary["SwiftUI APIs"]
Bundle --> V1
V1 --> Boundary
Bundle --> V2
V2 --> Boundary
Reference code
End/FlashCard/SwiftDataFlashCardSample.swift:11 — architecture anchor
@main
struct SwiftDataFlashCardSample: App {
// ...
}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
CardEditorView o-- Card : card
CardEditorView o-- FocusedField : focusedField
CardContainerView o-- Content : content
CardReaderView o-- Color : color
Ownership evidence
End/FlashCard/Views/CardEditorView.swift:11 — stored dependency or nearest verified ownership anchor
struct CardEditorView: View {
@Bindable var card: Card
// ...
}| Owner | Object or state | Relationship | Mutation authority |
|---|---|---|---|
CardEditorView |
Card (card) |
stores or receives | App/module collaborators |
CardEditorView |
FocusedField (focusedField) |
stores or receives | Owning lexical scope |
CardContainerView |
Content (content) |
stores or receives | App/module collaborators |
CardReaderView |
Color (color) |
stores or receives | 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
End/FlashCard/Views/CardEditorView.swift:10 — representative type boundary
struct CardEditorView: View {
// ...
}| Type | Responsibility | Depends on or conforms to |
|---|---|---|
CardEditorView |
User-interface presentation and input forwarding | View |
CardEditorView |
User-interface presentation and input forwarding | View |
CardContainerView |
User-interface presentation and input forwarding | Concrete collaborators/imported frameworks |
CardReaderView |
User-interface presentation and input forwarding | View |
ContentView |
User-interface presentation and input forwarding | View |
FlashCardView |
User-interface presentation and input forwarding | View |
CardContainerView |
User-interface presentation and input forwarding | Concrete collaborators/imported frameworks |
CardReaderView |
User-interface presentation and input forwarding | View |
ContentView |
User-interface presentation and input forwarding | View |
FlashCardView |
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 |
|---|---|---|---|
selectedCardID (End/FlashCard/Views/CardCarousel.swift:13) |
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. |
focusCardID (End/FlashCard/Views/CardCarousel.swift:14) |
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. |
initialCardID (End/FlashCard/Views/CardCarousel.swift:15) |
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. |
focusedField (End/FlashCard/Views/CardEditorView.swift:12) |
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
End/FlashCard/Views/CardCarousel.swift:13 — representative boundary
@State private var selectedCardID: PersistentIdentifier?
@FocusState private var focusCardID: PersistentIdentifier?
private let initialCardID: PersistentIdentifier
let editing: Bool
var cards: [Card]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 |
|---|---|---|
| User-interface presentation and input forwarding | CardContainerView, CardEditorView, CardReaderView, ContentView |
The source’s View suffix makes this role explicit. |
Design patterns
| Pattern | Source evidence | Purpose or tradeoff |
|---|---|---|
| Binding-based state propagation | End/FlashCard/Views/CardGallery.swift:12 |
A binding exposes controlled read/write access while the upstream owner remains authoritative. |
| Publisher-backed observable state | Start/FlashCard/Model/Card.swift:11 |
Published properties notify observers while mutation remains with the state object. |
| Actor-isolated state | End/FlashCard/Support/PreviewSampleData.swift:10 |
Actor annotations make the concurrency ownership boundary explicit. |
Naming conventions
- Types: View: CardContainerView, CardEditorView, CardReaderView, ContentView, FlashCardView.
- Protocols: no local protocol declaration in the scanned source.
- Methods:
makeBody. - Files:
End/FlashCard/SwiftDataFlashCardSample.swift,Start/FlashCard/SwiftDataFlashCardSample.swift,End/FlashCard/Views/CardEditorView.swift,Start/FlashCard/Views/CardEditorView.swift,End/FlashCard/Views/CardContainerView.swift,End/FlashCard/Views/CardReaderView.swift.
Architecture takeaways
SwiftDataFlashCardSampleis the main source-visible entry or composition anchor for this sample.- Framework work reaches SwiftUI, SwiftData, UniformTypeIdentifiers 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 |
|---|---|
End/FlashCard/SwiftDataFlashCardSample.swift |
SwiftDataFlashCardSample |
Start/FlashCard/SwiftDataFlashCardSample.swift |
SwiftDataFlashCardSample |
End/FlashCard/Views/CardEditorView.swift |
CardEditorView, FocusedField, CardFieldLabeledContentStyle |
Start/FlashCard/Views/CardEditorView.swift |
CardEditorView, FocusedField, CardFieldLabeledContentStyle |
End/FlashCard/Views/CardContainerView.swift |
CardContainerView |
End/FlashCard/Views/CardReaderView.swift |
CardReaderView |
End/FlashCard/Views/ContentView.swift |
ContentView |
End/FlashCard/Views/FlashCardView.swift |
FlashCardView |
Start/FlashCard/Views/CardContainerView.swift |
CardContainerView |
Start/FlashCard/Views/CardReaderView.swift |
CardReaderView |