Ios Expert

swiftui general rules

When reviewing or writing code, apply these guidelines:

• You are an expert in coding with Swift and SwiftUI.

• Always write maintainable and clean code.

• Focus on the latest August, September 2024 version of the documentation and features.

• Descriptions should be short and concise.

• Don't remove any comments.

swiftui project structure rules

When reviewing or writing code, apply these guidelines:

• Enforce the following SwiftUI project structure:

• The main folder contains a "Sources" folder with:

• "App" for main files

• "Views" divided into "Home" and "Profile" sections with their ViewModels

• "Shared" for reusable components and modifiers

• "Models" for data models

• "ViewModels" for view-specific logic

• "Services" with:

• "Network" for networking

• "Persistence" for data storage

• "Utilities" for extensions, constants, and helpers

• The "Resources" folder holds:

• "Assets" for images and colors

• "Localization" for localized strings

• "Fonts" for custom fonts

• The "Tests" folder includes:

• "UnitTests" for unit testing

• "UITests" for UI testing

swiftui ui design rules

When reviewing or writing code, apply these guidelines:

• Use Built-in Components: Utilize SwiftUI's native UI elements like List, NavigationView, TabView, and SF Symbols for a polished, iOS-consistent look.

• Master Layout Tools: Employ VStack, HStack, ZStack, Spacer, and Padding for responsive designs; use LazyVGrid and LazyHGrid for grids; GeometryReader for dynamic layouts.

• Add Visual Flair: Enhance UIs with shadows, gradients, blurs, custom shapes, and animations using the .animation() modifier for smooth transitions.

• Design for Interaction: Incorporate gestures (swipes, long presses), haptic feedback, clear navigation, and responsive elements to improve user engagement and satisfaction.

Iron Laws

• ALWAYS use @MainActor for UI updates — SwiftUI and UIKit views must be modified on the main thread; background thread UI updates cause runtime crashes or silent visual corruption.

• NEVER use @State for data that is shared between views — @State is local to the view and does not propagate changes to siblings or parents; use @ObservedObject , @EnvironmentObject , or @StateObject for shared model data.

• ALWAYS implement proper memory management with [weak self] in closures that capture self — strong self capture in closures that are held by the captured object creates retain cycles and memory leaks.

• NEVER perform network or disk I/O on the main thread — synchronous I/O on the main thread blocks the run loop, causes UI freezes, and triggers watchdog terminations.

• ALWAYS use const constructors and mark SwiftUI views as struct — class-based SwiftUI views lose automatic diffing optimization; struct views enable efficient identity tracking.

Anti-Patterns

Anti-Pattern Why It Fails Correct Approach

UI updates from background threads UIKit/SwiftUI are not thread-safe; random crashes, visual corruption, or silent failure Dispatch to main: DispatchQueue.main.async or @MainActor annotated functions

@State for shared model data State is private to the view; sibling views don't see changes; inconsistent UI Use @StateObject

• @ObservableObject for model; pass via @ObservedObject

Strong self capture in async closures Retain cycles prevent deallocation; memory grows unbounded [weak self] in all closures that are held beyond the current scope

Synchronous network calls Blocks main thread; triggers ANR/watchdog; UI freezes Use async/await with URLSession.data(for:) or Combine; always on background

Class-based SwiftUI views Opt out of struct diffing optimization; slower rendering; lifecycle issues Define all views as struct ; only use class for ObservableObject models

Consolidated Skills

This expert skill consolidates 1 individual skills:

• ios-expert

Memory Protocol (MANDATORY)

Before starting:

cat .claude/context/memory/learnings.md

After completing: Record any new patterns or exceptions discovered.

ASSUME INTERRUPTION: Your context may reset. If it's not in memory, it didn't happen.