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

Configuring your app to use alternate app icons

At a glance

Item Summary
Purpose Add alternate app icons to your app, and let people choose which icon to display.
App architecture A Swift sample with the source-visible chain AlternateAppIconContentViewModelSwiftUI / UIKit APIs.
Main patterns SwiftUI environment injection, Actor-isolated state
Project style 5 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

Project structure

Source bundle/
├── AlternateAppIcon/
│   ├── AlternateAppIcon.swift
│   ├── ContentView.swift
│   ├── Model.swift
│   ├── Icon.swift
│   └── IconChooser.swift
├── AlternateAppIcon.xcodeproj/
│   ├── .xcodesamplecode.plist
│   └── project.pbxproj
└── 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 3 project/configuration file(s) and 5 source declaration(s).

Overall architecture

Reference code

AlternateAppIcon/AlternateAppIcon.swift:10 — architecture anchor

@main
struct AlternateAppIcon: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

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 Xcode.

Ownership and state

Ownership evidence

AlternateAppIcon/ContentView.swift:11 — stored dependency or nearest verified ownership anchor

    @State private var model = Model()
Owner Object or state Relationship Mutation authority
ContentView Model (model) owns wrapper-managed state Owning lexical scope
Model Icon (appIcon) stores or receives App/module collaborators
Model Logger (logger) creates and retains Initialized by the owner; the binding is immutable
IconChooser Model (model) receives environment-provided state The environment provider is authoritative

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

AlternateAppIcon/ContentView.swift:10 — representative type boundary

struct ContentView: View {
    // ...
}
Type Responsibility Depends on or conforms to
ContentView User-interface presentation and input forwarding View
Model Feature data or observable state Concrete collaborators/imported frameworks
AlternateAppIcon Represents a feature value or composable behavior App
Icon Defines a closed set of feature states or choices String, CaseIterable, Identifiable
IconChooser 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
model (AlternateAppIcon/ContentView.swift:11) 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.
columns (AlternateAppIcon/IconChooser.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.
logger (AlternateAppIcon/Model.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.

Reference code

AlternateAppIcon/ContentView.swift:11 — representative boundary

    @State private var model = Model()
     
    var body: some View {
        IconChooser()
            .environment(model)
    }

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
Feature data or observable state Model The source’s Model suffix makes this role explicit.
User-interface presentation and input forwarding ContentView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
SwiftUI environment injection AlternateAppIcon/IconChooser.swift:11 The environment supplies state or a capability without threading it through every initializer.
Actor-isolated state AlternateAppIcon/Model.swift:12 Actor annotations make the concurrency ownership boundary explicit.

Naming conventions

  • Types: Model: Model; View: ContentView.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: setAlternateAppIcon.
  • Files: AlternateAppIcon/AlternateAppIcon.swift, AlternateAppIcon/ContentView.swift, AlternateAppIcon/Model.swift, AlternateAppIcon/Icon.swift, AlternateAppIcon/IconChooser.swift.

Architecture takeaways

  • AlternateAppIcon is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, UIKit 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
AlternateAppIcon/AlternateAppIcon.swift AlternateAppIcon
AlternateAppIcon/ContentView.swift ContentView
AlternateAppIcon/Model.swift Model
AlternateAppIcon/Icon.swift Icon
AlternateAppIcon/IconChooser.swift IconChooser