Swift-UIKit-Skill

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:

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