Sample CodeiOS, iPadOS, Mac CatalystReviewed 2026-07-21View on Apple Developer

Implementing an inline Photos picker

At a glance

Item Summary
Purpose Embed a system-provided, half-height Photos picker into your app’s view.
App architecture A Swift sample with the source-visible chain InlinePhotosPickerDemoAppContentViewContentViewModelPhotosUI APIs.
Main patterns Model-View-ViewModel, Publisher-backed observable state, Actor-isolated state
Project style 3 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

Project structure

Source bundle/
├── PhotosPickerDemo/
│   ├── InlinePhotosPickerDemoApp.swift
│   ├── ContentViewModel.swift
│   └── ContentView.swift
├── Configuration/
│   └── SampleCode.xcconfig
└── InlinePhotosPickerDemo.xcodeproj/
    ├── .xcodesamplecode.plist
    └── project.pbxproj

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 3 project/configuration file(s) and 8 source declaration(s).

Overall architecture

Reference code

PhotosPickerDemo/InlinePhotosPickerDemoApp.swift:11 — architecture anchor

@main
struct InlinePhotosPickerDemoApp: 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 PhotosUI.

Ownership and state

Ownership evidence

PhotosPickerDemo/ContentViewModel.swift:44 — stored dependency or nearest verified ownership anchor

        private let pickerItem: PhotosPickerItem
        
        /// A load progress for the photo.
        @Published var imageStatus: Status?
        
        /// A textual description for the photo.
        @Published var imageDescription: String = ""
Owner Object or state Relationship Mutation authority
ImageAttachment PhotosPickerItem (pickerItem) stores or receives Initialized by the owner; the binding is immutable
ImageAttachment Status (imageStatus) stores or receives App/module collaborators
ImageAttachment String (imageDescription) owns value state App/module collaborators
ContentView ContentViewModel (viewModel) owns wrapper-managed state Owning lexical scope

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

PhotosPickerDemo/InlinePhotosPickerDemoApp.swift:12 — representative type boundary

struct InlinePhotosPickerDemoApp: App {
    // ...
}
Type Responsibility Depends on or conforms to
InlinePhotosPickerDemoApp Application entry and top-level composition App
ContentViewModel UI-facing state and feature coordination ObservableObject
ContentView User-interface presentation and input forwarding View
ImageAttachmentView User-interface presentation and input forwarding View
ImageAttachment Owns feature behavior and collaborator lifecycle ObservableObject, Identifiable
Status Defines a closed set of feature states or choices Concrete collaborators/imported frameworks
LoadingError Represents feature failure conditions Error
ImageList Represents a feature value or composable behavior 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
viewModel (PhotosPickerDemo/ContentView.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.
pickerItem (PhotosPickerDemo/ContentViewModel.swift:44) 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.
attachmentByIdentifier (PhotosPickerDemo/ContentViewModel.swift:105) 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

PhotosPickerDemo/ContentView.swift:15 — representative boundary

struct ContentView: View {
    // ...
    @StateObject private var viewModel = ContentViewModel()
    // ...
}

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 InlinePhotosPickerDemoApp The source’s App suffix makes this role explicit.
User-interface presentation and input forwarding ContentView, ImageAttachmentView The source’s View suffix makes this role explicit.
UI-facing state and feature coordination ContentViewModel The source’s ViewModel suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Model-View-ViewModel PhotosPickerDemo/ContentViewModel.swift:12 Role-named view models keep UI-facing state or coordination outside view declarations.
Publisher-backed observable state PhotosPickerDemo/ContentViewModel.swift:47 Published properties notify observers while mutation remains with the state object.
Actor-isolated state PhotosPickerDemo/ContentViewModel.swift:12 Actor annotations make the concurrency ownership boundary explicit.

Naming conventions

  • Types: App: InlinePhotosPickerDemoApp; View: ContentView, ImageAttachmentView; ViewModel: ContentViewModel.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: loadImage.
  • Files: PhotosPickerDemo/InlinePhotosPickerDemoApp.swift, PhotosPickerDemo/ContentViewModel.swift, PhotosPickerDemo/ContentView.swift.

Architecture takeaways

  • InlinePhotosPickerDemoApp is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, PhotosUI 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
PhotosPickerDemo/InlinePhotosPickerDemoApp.swift InlinePhotosPickerDemoApp
PhotosPickerDemo/ContentViewModel.swift ContentViewModel, ImageAttachment, Status, LoadingError
PhotosPickerDemo/ContentView.swift ContentView, ImageList, ImageAttachmentView