UIKit & Bridging

You MUST use this skill for ANY UIKit bridging, Auto Layout, Combine, TextKit, or UIKit animation work.

Quick Reference

Symptom / Task	Reference
UIViewRepresentable, UIViewControllerRepresentable	See `skills/uikit-bridging.md`
Embedding SwiftUI in UIKit (UIHostingController)	See `skills/uikit-bridging.md`
Coordinator pattern, updateUIView lifecycle	See `skills/uikit-bridging.md`
"Unable to simultaneously satisfy constraints"	See `skills/auto-layout-debugging.md`
Constraint conflicts, ambiguous layout	See `skills/auto-layout-debugging.md`
Views not appearing, positioned incorrectly	See `skills/auto-layout-debugging.md`
CAAnimation completion handler not firing	See `skills/uikit-animation-debugging.md`
Spring physics wrong on device, duration mismatch	See `skills/uikit-animation-debugging.md`
Animation jank, CATransaction timing	See `skills/uikit-animation-debugging.md`
Combine publishers, AnyCancellable lifecycle	See `skills/combine-patterns.md`
@Published properties, Combine ↔ async/await	See `skills/combine-patterns.md`
When to use Combine vs async/await	See `skills/combine-patterns.md`
TextKit 2 architecture, NSTextLayoutManager	See `skills/textkit-ref.md`
Writing Tools integration (iOS 26)	See `skills/textkit-ref.md`
SwiftUI TextEditor, TextKit 1 migration	See `skills/textkit-ref.md`

Decision Tree

dot

digraph uikit {
    start [label="UIKit task" shape=ellipse];
    what [label="What do you need?" shape=diamond];

    start -> what;
    what -> "skills/uikit-bridging.md" [label="wrap UIKit in SwiftUI\nor SwiftUI in UIKit"];
    what -> "skills/auto-layout-debugging.md" [label="constraint errors,\nlayout issues"];
    what -> "skills/uikit-animation-debugging.md" [label="CAAnimation bugs,\nspring physics,\ncompletion handlers"];
    what -> "skills/combine-patterns.md" [label="publishers, sinks,\n@Published,\nasync/await bridge"];
    what -> "skills/textkit-ref.md" [label="text layout,\nWriting Tools,\nTextKit migration"];
}

UIViewRepresentable / UIViewControllerRepresentable / UIHostingController? →
```
skills/uikit-bridging.md
```
"Unable to simultaneously satisfy constraints" / layout bugs? →
```
skills/auto-layout-debugging.md
```
CAAnimation completion missing / spring physics wrong / animation jank? →
```
skills/uikit-animation-debugging.md
```
Combine publishers / AnyCancellable / @Published / Combine ↔ async bridge? →
```
skills/combine-patterns.md
```
TextKit 2 / Writing Tools / TextEditor / TextKit 1 migration? →
```
skills/textkit-ref.md
```
Pure SwiftUI view question (no UIKit bridging)? →
```
/skill axiom-swiftui
```
Design decisions, HIG, Liquid Glass, SF Symbols, typography? →
```
/skill axiom-design
```
Block retain cycles in UIKit callbacks? → See axiom-performance (
```
skills/objc-block-retain-cycles.md
```
)
Memory leaks from Combine subscriptions? → Start with
```
skills/combine-patterns.md
```
, then axiom-performance if leak persists

Conflict Resolution

uikit vs swiftui: When working with UI code:

Use uikit when wrapping UIKit in SwiftUI or vice versa, or debugging UIKit-specific issues (Auto Layout, CAAnimation)
Use swiftui for pure SwiftUI views, navigation, layout, animations

uikit vs concurrency: When Combine interacts with async/await:

Use uikit (
```
skills/combine-patterns.md
```
) for bridging Combine pipelines with async/await
Use concurrency for pure async/await patterns, actors, Sendable

uikit vs performance: When animations or layout cause performance issues:

Try uikit FIRST — Most animation jank is CATransaction timing or layer state, not a profiling issue
Only use performance if animation logic is correct but rendering is slow

uikit vs axiom-data: When @Published properties relate to data persistence:

Use uikit for Combine publisher patterns and @Published lifecycle
Use axiom-data for SwiftData/Core Data model layer concerns

Anti-Rationalization

Thought	Reality
"I'll just use UIHostingController, it's simple"	Hosting has sizing, lifecycle, and navigation edge cases. `skills/uikit-bridging.md` covers the gotchas.
"Auto Layout error is just a warning, I'll ignore it"	Unsatisfied constraints cause unpredictable layout at runtime. Fix them now.
"I know how CAAnimation works"	90% of CAAnimation bugs are CATransaction timing, not Core Animation. Check `skills/uikit-animation-debugging.md` .
"Combine is dead, just rewrite with async/await"	Combine has no deprecation notice. Rewriting working pipelines wastes time. `skills/combine-patterns.md` covers when to migrate vs maintain.
"TextKit 1 still works fine"	TextKit 1 misses Writing Tools integration and has known layout bugs Apple won't fix. See `skills/textkit-ref.md` .
"I'll store cancellables in a local variable"	Local AnyCancellable deallocates immediately, killing the subscription.

Example Invocations

User: "How do I wrap a UIKit view in SwiftUI?" → Read:

skills/uikit-bridging.md

User: "I'm getting 'Unable to simultaneously satisfy constraints'" → Read:

skills/auto-layout-debugging.md

User: "My CAAnimation completion handler never fires" → Read:

skills/uikit-animation-debugging.md

User: "Should I use Combine or async/await for this?" → Read:

skills/combine-patterns.md

User: "How do I integrate Writing Tools with my text editor?" → Read:

skills/textkit-ref.md

User: "My SwiftUI view has a memory leak from a Combine subscription" → Read:

skills/combine-patterns.md

User: "How do I embed SwiftUI in my UIKit app?" → Read:

skills/uikit-bridging.md

axiom-uikit

NPX Install

Tags

SKILL.md Content