Adopting drag and drop using SwiftUI
At a glance
| Item | Summary |
|---|---|
| Purpose | Enable drag-and-drop interactions in lists, tables and custom views. |
| App architecture | A Swift sample with the source-visible chain AdoptingDragAndDropInASwiftUIAppApp → ContentView → DataModel → SwiftUI APIs. |
| Main patterns | Binding-based state propagation |
| Project style | 12 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries. |
Project structure
Source bundle/
└── AdoptingDragAndDropInASwiftUIApp/
├── AdoptingDragAndDropInASwiftUIAppApp.swift
├── Models/
│ ├── DataModel.swift
│ ├── Constants.swift
│ └── Contact.swift
└── Views/
├── ContactDetailView.swift
├── ContactInfoView.swift
├── HeaderView.swift
├── ContentView.swift
├── ThumbnailView.swift
├── ContactsTable.swift
├── ContactList.swift
└── DisplayModePicker.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 5 project/configuration file(s) and 18 source declaration(s).
Overall architecture
flowchart LR
N1["AdoptingDragAndDropInASwiftUIAppApp"]
N2["ContentView"]
N3["DataModel"]
N4["SwiftUI APIs"]
N1 --> N2
N2 --> N3
N3 --> N4
Reference code
AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.swift:10 — architecture anchor
@main
struct AdoptingDragAndDropInASwiftUIApp: App {
// ...
}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 SwiftUI.
Ownership and state
classDiagram
AdoptingDragAndDropInASwiftUIApp *-- DataModel : dataModel
DataModel *-- Array : contacts
DataModel o-- DisplayMode : displayMode
Video *-- URL : url
Ownership evidence
AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.swift:12 — stored dependency or nearest verified ownership anchor
@State private var dataModel = DataModel()| Owner | Object or state | Relationship | Mutation authority |
|---|---|---|---|
AdoptingDragAndDropInASwiftUIApp |
DataModel (dataModel) |
owns wrapper-managed state | Owning lexical scope |
DataModel |
Array (contacts) |
owns value state | App/module collaborators |
DataModel |
DisplayMode (displayMode) |
stores or receives | App/module collaborators |
Video |
URL (url) |
owns value state | App/module collaborators |
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
AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.swift:11 — representative type boundary
struct AdoptingDragAndDropInASwiftUIApp: App {
// ...
}| Type | Responsibility | Depends on or conforms to |
|---|---|---|
AdoptingDragAndDropInASwiftUIApp |
Application entry and top-level composition | App |
DataModel |
Feature data or observable state | Concrete collaborators/imported frameworks |
ContactDetailView |
User-interface presentation and input forwarding | View |
ContactInfoView |
User-interface presentation and input forwarding | View |
HeaderView |
User-interface presentation and input forwarding | View |
VideoView |
User-interface presentation and input forwarding | View |
ContentView |
User-interface presentation and input forwarding | View |
ThumbnailView |
User-interface presentation and input forwarding | View |
CompactContactView |
User-interface presentation and input forwarding | View |
VideoLabelView |
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 |
|---|---|---|---|
dataModel (AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.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. |
dataModel (AdoptingDragAndDropInASwiftUIApp/Views/ContactList.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. |
isTargeted (AdoptingDragAndDropInASwiftUIApp/Views/ContactList.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. |
horizontalSizeClass (AdoptingDragAndDropInASwiftUIApp/Views/ContactsTable.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
AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.swift:12 — representative boundary
@State private var dataModel = DataModel()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 |
|---|---|---|
| Application entry and top-level composition | AdoptingDragAndDropInASwiftUIApp |
The source’s App suffix makes this role explicit. |
| Feature data or observable state | DataModel |
The source’s Model suffix makes this role explicit. |
| User-interface presentation and input forwarding | CompactContactView, ContactDetailView, ContactInfoView, ContentView |
The source’s View suffix makes this role explicit. |
Design patterns
| Pattern | Source evidence | Purpose or tradeoff |
|---|---|---|
| Binding-based state propagation | AdoptingDragAndDropInASwiftUIApp/Views/DisplayModePicker.swift:11 |
A binding exposes controlled read/write access while the upstream owner remains authoritative. |
Naming conventions
- Types: App: AdoptingDragAndDropInASwiftUIApp; Model: DataModel; View: CompactContactView, ContactDetailView, ContactInfoView, ContentView, HeaderView.
- Protocols: no local protocol declaration in the scanned source.
- Methods:
handleDroppedContacts,loadImage,loadItem,copyLibraryFile,makeBody. - Files:
AdoptingDragAndDropInASwiftUIApp/Models/DataModel.swift,AdoptingDragAndDropInASwiftUIApp/Views/ContactDetailView.swift,AdoptingDragAndDropInASwiftUIApp/Views/ContactInfoView.swift,AdoptingDragAndDropInASwiftUIApp/Views/HeaderView.swift,AdoptingDragAndDropInASwiftUIApp/Views/ContentView.swift,AdoptingDragAndDropInASwiftUIApp/Views/ThumbnailView.swift.
Architecture takeaways
AdoptingDragAndDropInASwiftUIAppAppis the main source-visible entry or composition anchor for this sample.- Framework work reaches SwiftUI, Contacts, PhotosUI, 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 |
|---|---|
AdoptingDragAndDropInASwiftUIApp/AdoptingDragAndDropInASwiftUIAppApp.swift |
AdoptingDragAndDropInASwiftUIApp |
AdoptingDragAndDropInASwiftUIApp/Models/DataModel.swift |
DataModel, Video |
AdoptingDragAndDropInASwiftUIApp/Views/ContactDetailView.swift |
ContactDetailView, DisplayMode |
AdoptingDragAndDropInASwiftUIApp/Views/ContactInfoView.swift |
ContactInfoView, ContactDetailLabelStyle |
AdoptingDragAndDropInASwiftUIApp/Views/HeaderView.swift |
HeaderView, VideoView |
AdoptingDragAndDropInASwiftUIApp/Views/ContentView.swift |
ContentView |
AdoptingDragAndDropInASwiftUIApp/Views/ThumbnailView.swift |
ThumbnailView |
AdoptingDragAndDropInASwiftUIApp/Views/ContactsTable.swift |
ContactTable, CompactContactView, VideoLabelView |
AdoptingDragAndDropInASwiftUIApp/Models/Constants.swift |
Constants |
AdoptingDragAndDropInASwiftUIApp/Models/Contact.swift |
Contact |