# Li Lance Android Seraphim Framework Flutter Performance

> Performance

- Skill: `tomevault-io/li-lance-android-seraphim-framework-flutter-performance` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/li-lance-android-seraphim-framework-flutter-performance`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/li-lance-android-seraphim-framework-flutter-performance/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/li-lance-android-seraphim-framework-flutter-performance

---


# Performance

## **Priority: P1 (OPERATIONAL)**

Performance optimization techniques for smooth 60fps Flutter applications.

- **Rebuilds**: Use `const` widgets and `buildWhen` / `select` for granular updates.
- **Lists**: Always use `ListView.builder` for item recycling.
- **Heavy Tasks**: Use `compute()` or `Isolates` for parsing/logic.
- **Repaints**: Use `RepaintBoundary` for complex animations. Use `debugRepaintRainbowEnabled` to
  debug.
- **Images**: Use `CachedNetworkImage` + `memCacheWidth`. `precachePicture` for SVGs.
- **Keys**: Provide `ValueKey` for list items and stable IDs for reconciliation.
- **Resource Cleanup**: Dispose controllers/streams in `dispose()`.
- **Pagination**: Default to 20 items per page for network lists.
- **Build Purity**: Keep `build` methods free of heavy work; move logic to BLoC/Application.
- **Image Resizing**: Always set `maxWidth`/`maxHeight` when loading images.

## Anti-Patterns

- ❌ `setState()` at the root/page level to update a single counter — use `BlocBuilder` with
  `buildWhen` or `context.select()` for granular rebuilds
- ❌ Sorting/filtering a list inside `build()` — move heavy computation to BLoC or use `compute()`
- ❌ Non-`const` leaf widgets that never change — always apply `const` to static widgets to skip
  reconciliation
- ❌ `Column(children: items.map((e) => ItemWidget(e)).toList())` for large lists — use
  `ListView.builder` for item recycling

```dart
BlocBuilder<UserBloc, UserState>(
  buildWhen: (p, c) => p.id != c.id,
  builder: (context, state) => Text(state.name),
)
```

---
> Source: [li-lance/android-seraphim-framework](https://github.com/li-lance/android-seraphim-framework) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-06-16 -->