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

Creating real-time games

At a glance

Item Summary
Purpose Develop games where multiple players interact in real time.
App architecture A Swift sample with the source-visible chain RealTimeGameSampleAppContentViewGameKit APIs.
Main patterns Delegate or data-source callbacks, Publisher-backed observable state, Actor-isolated state
Project style 15 scanned source file(s) across Swift, organized around ranked entry, type, and file boundaries.

Project structure

Source bundle/
└── Real-Time Game Sample/
    ├── RealTimeGameSampleApp.swift
    ├── GameView.swift
    ├── ChatView.swift
    ├── ContentView.swift
    ├── FriendsView.swift
    ├── MessageView.swift
    ├── RealTimeGame+GKGameCenterViewController.swift
    ├── RealTimeGame+GKMatchDelegate.swift
    ├── RealTimeGame+GKMatchmakerViewControllerDelegate.swift
    ├── RealTimeGame+Friends.swift
    ├── RealTimeGame+MatchData.swift
    └── RealTimeGame+Messages.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 4 project/configuration file(s) and 12 source declaration(s).

Overall architecture

Reference code

Real-Time Game Sample/RealTimeGameSampleApp.swift:10 — architecture anchor

@main
struct RealTimeGameSampleApp: 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 GameKit.

Ownership and state

Ownership evidence

Real-Time Game Sample/GameView.swift:13 — stored dependency or nearest verified ownership anchor

struct GameView: View {
    // ...
    @ObservedObject var game: RealTimeGame
    // ...
}
Owner Object or state Relationship Mutation authority
GameView RealTimeGame (game) observes externally owned state The observed object is authoritative
ChatView RealTimeGame (game) observes externally owned state The observed object is authoritative
ChatView String (typingMessage) owns wrapper-managed state Owning lexical scope
ContentView RealTimeGame (game) 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

Real-Time Game Sample/RealTimeGameSampleApp.swift:11 — representative type boundary

struct RealTimeGameSampleApp: App {
    // ...
}
Type Responsibility Depends on or conforms to
RealTimeGameSampleApp Application entry and top-level composition App
GameView User-interface presentation and input forwarding View
ChatView User-interface presentation and input forwarding View
ContentView User-interface presentation and input forwarding View
FriendsView User-interface presentation and input forwarding View
MessageView User-interface presentation and input forwarding View
ChatToggleStyle Represents a feature value or composable behavior ToggleStyle
MessageButtonStyle Represents a feature value or composable behavior ButtonStyle
Friend Represents a feature value or composable behavior Identifiable
GameData Represents feature data Codable

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
typingMessage (Real-Time Game Sample/ChatView.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.
game (Real-Time Game Sample/ContentView.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.
showFriends (Real-Time Game Sample/ContentView.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.
showMessages (Real-Time Game Sample/GameView.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.

Reference code

Real-Time Game Sample/ChatView.swift:13 — representative boundary

struct ChatView: View {
    // ...
    @State private var typingMessage: String = ""
    
    // ...
}

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 RealTimeGameSampleApp The source’s App suffix makes this role explicit.
User-interface presentation and input forwarding ChatView, ContentView, FriendsView, GameView The source’s View suffix makes this role explicit.

Design patterns

Pattern Source evidence Purpose or tradeoff
Delegate or data-source callbacks Real-Time Game Sample/RealTimeGame.swift:14 Callback protocols invert event delivery back into the sample’s owner.
Publisher-backed observable state Real-Time Game Sample/RealTimeGame.swift:16 Published properties notify observers while mutation remains with the state object.
Actor-isolated state Real-Time Game Sample/RealTimeGame.swift:13 Actor annotations make the concurrency ownership boundary explicit.

Naming conventions

  • Types: App: RealTimeGameSampleApp; View: ChatView, ContentView, FriendsView, GameView, MessageView.
  • Protocols: no local protocol declaration in the scanned source.
  • Methods: makeBody, showProgress, topScore, gameCenterViewControllerDidFinish, match.
  • Files: Real-Time Game Sample/RealTimeGameSampleApp.swift, Real-Time Game Sample/GameView.swift, Real-Time Game Sample/ChatView.swift, Real-Time Game Sample/ContentView.swift, Real-Time Game Sample/FriendsView.swift, Real-Time Game Sample/MessageView.swift.

Architecture takeaways

  • RealTimeGameSampleApp is the main source-visible entry or composition anchor for this sample.
  • Framework work reaches SwiftUI, GameKit 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
Real-Time Game Sample/RealTimeGameSampleApp.swift RealTimeGameSampleApp
Real-Time Game Sample/GameView.swift GameView, ChatToggleStyle, MessageButtonStyle, GameViewPreviews
Real-Time Game Sample/ChatView.swift ChatView, ChatViewPreviews
Real-Time Game Sample/ContentView.swift ContentView, ContentView_Previews
Real-Time Game Sample/FriendsView.swift FriendsView, FriendsIView_Previews
Real-Time Game Sample/MessageView.swift MessageView, MessageViewPreviews
Real-Time Game Sample/RealTimeGame+GKGameCenterViewController.swift Feature implementation
Real-Time Game Sample/RealTimeGame+GKMatchDelegate.swift Feature implementation
Real-Time Game Sample/RealTimeGame+GKMatchmakerViewControllerDelegate.swift Feature implementation
Real-Time Game Sample/RealTimeGame+Friends.swift Friend