uikit-expert-skill

name	uikit-expert-skill
description	Write, review, and modernize UIKit code for legacy-to-modern iOS apps (iOS 12+ through latest). Use when building UIKit screens, refactoring massive view controllers, optimizing table/collection rendering, improving animation/layout/state patterns, applying modern APIs with iOS 12-safe fallbacks, and planning incremental UIKit↔SwiftUI migration with measurable quality gates.

UIKit Expert Skill

Overview

Use this skill as the UIKit-specific counterpart to swiftui-expert-skill.

It is optimized for:

• legacy UIKit projects (including iOS 12 target support)
• mixed UIKit/SwiftUI migration contexts
• performance-sensitive list and card-heavy interfaces

Workflow Decision Tree

1) Review existing UIKit screen

• Validate lifecycle usage and ownership boundaries.
• Check layout correctness (safe area, constraints, self-sizing).
• Check update strategy (reloadData overuse, invalidation churn).
• Check rendering hotspots (shadow, blur, repeated measurement, image decode).
• Check accessibility and Dynamic Type behavior.

2) Refactor existing UIKit implementation

• Replace fragile layout hacks with anchor/inset-driven layout.
• Move broad updates to targeted row/item updates.
• Extract reusable view/cell components.
• Add async/state guards to prevent stale completion writes.
• Add availability-gated modern APIs with equivalent iOS 12 fallbacks.

3) Build new UIKit feature

• Define explicit state model and ownership.
• Build with Auto Layout anchors and safe area.
• Choose table/collection patterns with stable identity.
• Implement loading/error/success state rendering.
• Add focused animation and performance constraints from day one.

Quality bar

For recommendations and edits, always include:

• Good vs bad pattern comparison
• Why the change matters (correctness/perf/maintainability)
• iOS 12 compatibility note when using newer APIs
• Validation checklist

Reference map

• references/state-management.md

• references/view-structure.md

• references/modern-apis.md

• references/layout-best-practices.md

• references/list-patterns.md

• references/performance-patterns.md

• references/scroll-patterns.md

• references/animation-basics.md

• references/animation-transitions.md

• references/animation-advanced.md

• references/image-optimization.md

• references/sheet-navigation-patterns.md

• references/text-formatting.md

• references/liquid-glass.md

• references/uikit-antipatterns.md

• references/legacy-uikit-to-modern-uikit.md

• references/uikit-to-swiftui-incremental.md

• references/performance-benchmarks.md

• references/testing-guidance.md

• references/data-source-strategy-by-ios-version.md

• references/prefetching-and-cancellation.md

• references/responsiveness-budget.md

• references/api-availability-matrix.md

• references/legacy-vs-modern-list-migration.md

• references/accessibility-engineering.md

• references/instruments-playbook.md

• references/state-machine-templates.md

• references/case-studies.md

Scope boundary

• Use this skill for UIKit implementation details.
• Use swiftui-expert-skill for SwiftUI-first implementation details.
• In mixed code, map concepts between skills but keep final recommendations framework-specific.