swift-uikit-skill

name	swift-uikit-skill
description	Build, review, and improve programmatic UIKit applications following proven patterns for Auto Layout, table views, collection views, navigation, animation, Core Data, networking, and architecture. Use when writing new UIKit features, refactoring existing view controllers, reviewing UIKit code quality, building custom controls, or implementing common iOS design patterns like load-and-retry, onboarding, or collapsible headers.
license	MIT
metadata	{"author":"Lakr233","version":"1.0.0","source":"swift-arcade"}

Swift UIKit Skill

Operating Rules

• All UI is built programmatically (no Storyboards). Always set translatesAutoresizingMaskIntoConstraints = false.
• Prefer NSLayoutConstraint.activate([...]) for batch constraint activation.
• Organize view controller code with extensions: separate style(), layout(), and protocol conformances.
• Use factory functions for repetitive UI element creation.
• Use weak references for delegates and [weak self] in closures to prevent retain cycles.
• Prefer Result<Success, Error> for async completion handlers.
• Always dispatch UI updates to the main thread from async callbacks.
• Extract custom views flush to their container; parent manages spacing.
• Use child view controllers for complex, self-contained screen sections.
• Consult relevant reference files before implementing any topic.

Task Workflow

Review existing UIKit code

• Read the code under review and identify which topics apply
• Run the Topic Router below for each relevant topic
• Check for retain cycles (missing weak delegates, missing [weak self])
• Verify Auto Layout completeness (unambiguous constraints, no warnings)
• Flag deprecated patterns (e.g., manual beginUpdates/endUpdates when Diffable is available)

Improve existing UIKit code

• Audit current implementation against the Topic Router topics
• Extract large view controllers into child VCs and custom views
• Replace inline UI creation with factory functions
• Migrate legacy table/collection view data sources to Diffable where appropriate
• Add proper error handling with Result types

Implement new UIKit feature

• Design data flow first: identify service, view model, view controller, and view layers
• Structure views for composition (extracted views + child view controllers)
• Apply correct animation patterns (constraint-based, Core Animation, or UIView)
• Use protocol-delegate for sustained relationships; closures for one-shot callbacks
• Add proper loading/error states

Topic Router

Consult the reference file for each topic relevant to the current task:

Topic	Reference
UITableView	references/uitableview.md
UICollectionView	references/uicollectionview.md
UINavigationController	references/uinavigationcontroller.md
UIScrollView	references/uiscrollview.md
Core Animation	references/core-animation.md
Core Graphics	references/core-graphics.md
Auto Layout animation	references/auto-layout-animation.md
Communication patterns	references/communication-patterns.md
Architecture patterns	references/architecture-patterns.md
View extraction	references/view-extraction.md
Navigation patterns	references/navigation-patterns.md
Design patterns (UI)	references/design-patterns.md
Networking	references/networking.md
Factory functions	references/factory-patterns.md
Nib / XIB patterns	references/nib-patterns.md
NSAttributedString	references/nsattributedstring.md
Gesture recognizers	references/gesture-recognizers.md
Custom controls	references/custom-controls.md
Currency formatting	references/currency-formatting.md
Deep linking	references/deep-linking.md

Correctness Checklist

These are hard rules -- violations are always bugs:

• Every programmatic view sets translatesAutoresizingMaskIntoConstraints = false
• Delegates are declared weak var delegate: SomeDelegate?
• Async closures capture [weak self] when referencing the owning object
• UI updates from async callbacks are dispatched to DispatchQueue.main
• beginUpdates() / endUpdates() bracket all batch table view mutations
• Diffable data source items conform to Hashable with stable identifiers
• Child view controllers follow the 3-step lifecycle: addChild(), addSubview(), didMove(toParent:)
• Custom views define intrinsicContentSize when they have a natural size
• NSFetchedResultsController delegate implements all three callbacks (willChange, didChange, didChangeContent)
• Core Animation model layer is updated after animation to persist final state
• NSLayoutConstraint.activate() is used instead of isActive = true one-by-one
• Factory functions return views with translatesAutoresizingMaskIntoConstraints already set to false

Quick Diagnostics

Symptom	Likely cause	Reference
View doesn't appear	Missing translatesAutoresizingMaskIntoConstraints = false	references/view-extraction.md
Table view crashes on insert	Data source count mismatch with beginUpdates	references/uitableview.md
Animation snaps to final state	Model layer not updated after CA animation	references/core-animation.md
Retain cycle / memory leak	Missing weak on delegate or [weak self]	references/communication-patterns.md
Scroll view doesn't scroll	Missing content size or broken constraint chain	references/uiscrollview.md
Shadow clipped by view	masksToBounds = true on layer	references/core-animation.md
Gradient/shadow wrong size	Set bounds-dependent layers in viewDidAppear	references/core-animation.md
Collection view empty	Forgot to register cell or data source nil	references/uicollectionview.md
Core Data threading crash	Accessing managed object on wrong queue	references/networking.md
Navigation bar title missing	Not setting title or navigationItem.title	references/uinavigationcontroller.md