Sample CodeiOS, iPadOS, Mac Catalyst, macOS, visionOSReviewed 2026-07-21View on Apple Developer

Building a cross-platform web browser

At a glance

Item Summary
Purpose Implement a browser on multiple platforms that loads content, manages navigation history, and saves favorite websites, using WebKit for SwiftUI.
App architecture A Swift sample with the source-visible chain WebKitForSwiftUIAppContentViewBrowserManagerCustomSchemeHandlerWebKit 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/
└── WebKitForSwiftUI/
    └── WebKitForSwiftUI/
        ├── WebKitForSwiftUIApp.swift
        ├── Models/
        │   ├── BrowserManager.swift
        │   └── FavoriteWebpage.swift
        ├── Browser/
        │   ├── BrowserView.swift
        │   ├── AddressBar.swift
        │   └── BrowserToolbar.swift
        ├── ContentView.swift
        └── Favorites/
            ├── FavoriteListView.swift
            ├── FavoriteRowView.swift
            ├── EditFavoriteSheet.swift
            ├── FavoriteContextMenu.swift
            └── FavoriteToolbar.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 3 project/configuration file(s) and 17 source declaration(s).

Overall architecture

Reference code

WebKitForSwiftUI/WebKitForSwiftUI/WebKitForSwiftUIApp.swift:11 — architecture anchor

@main
struct WebKitForSwiftUIApp: 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 WebKit.

Ownership and state

Ownership evidence

WebKitForSwiftUI/WebKitForSwiftUI/Models/BrowserManager.swift:14 — stored dependency or nearest verified ownership anchor

    let page: WebPage
    let privateBrowsingEnabled: Bool
    var favorites = FavoriteWebpage.myFavorites

    var favoritesArray: [FavoriteWebpage] {
        Array(favorites.values)
    }
Owner Object or state Relationship Mutation authority
BrowserManager WebPage (page) stores or receives Initialized by the owner; the binding is immutable
BrowserManager Bool (privateBrowsingEnabled) owns value state Initialized by the owner; the binding is immutable
BrowserManager String (displayUrl) owns value state App/module collaborators
BrowserManager UserInterfaceSizeClass (horizontalSizeClass) stores or receives 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

WebKitForSwiftUI/WebKitForSwiftUI/WebKitForSwiftUIApp.swift:12 — representative type boundary

struct WebKitForSwiftUIApp: App {
    // ...
}
Type Responsibility Depends on or conforms to
WebKitForSwiftUIApp Application entry and top-level composition App
BrowserManager Long-lived feature or framework coordination Concrete collaborators/imported frameworks
NavigationPolicyHandler Handles callbacks or feature events WebPage.NavigationDeciding
CustomSchemeHandler Handles callbacks or feature events URLSchemeHandler
BrowserView User-interface presentation and input forwarding View
ContentView User-interface presentation and input forwarding View
FavoriteListView User-interface presentation and input forwarding View
FavoriteRowView User-interface presentation and input forwarding View
BrowserSettings Carries feature or framework configuration Codable, Hashable
FavoriteWebpage Represents a feature value or composable behavior Hashable, Identifiable

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
browserManager (WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.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.
navigate (WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.swift:42) private Use is restricted to the lexical declaration and same-file extensions allowed by Swift. Inference: hide an implementation step that is not part of the collaboration surface.
toolbarPlacement (WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.swift:52) 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.
toolbarPlacement (WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.swift:54) 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

WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.swift:13 — representative boundary

    @Environment(BrowserManager.self) private var browserManager

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 WebKitForSwiftUIApp The source’s App suffix makes this role explicit.
Handles callbacks or feature events CustomSchemeHandler, NavigationPolicyHandler The source’s Handler suffix makes this role explicit.
Long-lived feature or framework coordination BrowserManager The source’s Manager suffix makes this role explicit.
User-interface presentation and input forwarding BrowserView, ContentView, FavoriteListView, FavoriteRowView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Binding-based state propagation WebKitForSwiftUI/WebKitForSwiftUI/Browser/BrowserToolbar.swift:59 A binding exposes controlled read/write access while the upstream owner remains authoritative.

Naming conventions

  • Types: App: WebKitForSwiftUIApp; Handler: CustomSchemeHandler, NavigationPolicyHandler; Manager: BrowserManager; View: BrowserView, ContentView, FavoriteListView, FavoriteRowView.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: deleteItem, navigateTo, addProtocolIfNecessary, copyToPasteboard, openURL, addFavorite, editItem, makeFavorite.
  • Files: WebKitForSwiftUI/WebKitForSwiftUI/WebKitForSwiftUIApp.swift, WebKitForSwiftUI/WebKitForSwiftUI/Models/BrowserManager.swift, WebKitForSwiftUI/WebKitForSwiftUI/Browser/BrowserView.swift, WebKitForSwiftUI/WebKitForSwiftUI/ContentView.swift, WebKitForSwiftUI/WebKitForSwiftUI/Favorites/FavoriteListView.swift, WebKitForSwiftUI/WebKitForSwiftUI/Favorites/FavoriteRowView.swift.

Architecture takeaways

  • WebKitForSwiftUIApp is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, WebKit, UniformTypeIdentifiers, LinkPresentation 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
WebKitForSwiftUI/WebKitForSwiftUI/WebKitForSwiftUIApp.swift WebKitForSwiftUIApp
WebKitForSwiftUI/WebKitForSwiftUI/Models/BrowserManager.swift BrowserManager, NavigationPolicyHandler, CustomSchemeHandler, BrowserSettings
WebKitForSwiftUI/WebKitForSwiftUI/Browser/BrowserView.swift BrowserView
WebKitForSwiftUI/WebKitForSwiftUI/ContentView.swift ContentView
WebKitForSwiftUI/WebKitForSwiftUI/Favorites/FavoriteListView.swift FavoriteListView
WebKitForSwiftUI/WebKitForSwiftUI/Favorites/FavoriteRowView.swift FavoriteRowView
WebKitForSwiftUI/WebKitForSwiftUI/Models/FavoriteWebpage.swift FavoriteWebpage
WebKitForSwiftUI/WebKitForSwiftUI/Browser/AddressBar.swift AddressFieldAndIcon, BrowserAddressBar
WebKitForSwiftUI/WebKitForSwiftUI/Browser/BrowserToolbar.swift BrowserToolbar, BrowserToolbarControls
WebKitForSwiftUI/WebKitForSwiftUI/Favorites/EditFavoriteSheet.swift EditFavoriteSheet