# Flutter > Build reliable Flutter apps avoiding state loss, widget rebuild traps, and async pitfalls. Use when this capability is needed. - Skill: `tomevault-io/flutter-2` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/flutter-2` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/flutter-2/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/flutter-2 --- ## Quick Reference | Topic | File | |-------|------| | setState, state loss, keys | `state.md` | | build method, context, GlobalKey | `widgets.md` | | FutureBuilder, dispose, mounted | `async.md` | | Context after pop, deep linking | `navigation.md` | | const, rebuilds, performance | `performance.md` | | Platform channels, null safety | `platform.md` | ## Critical Rules - `setState` after dispose — check `mounted` before calling, crashes otherwise - Key missing on list items — reordering breaks state, always use keys - FutureBuilder rebuilds on parent rebuild — triggers future again, cache the Future - BuildContext after async gap — context may be invalid, check `mounted` first - `const` constructor — prevents rebuilds, use for static widgets - `StatefulWidget` recreated — key change or parent rebuild creates new state - GlobalKey expensive — don't use just to access state, pass callbacks instead - `dispose` incomplete — cancel timers, subscriptions, controllers - Navigator.pop with result — returns Future, don't ignore errors - ScrollController not disposed — memory leak - Image caching — use `cached_network_image`, default doesn't persist - PlatformException not caught — platform channel calls can throw --- > Source: [clawic/skills](https://github.com/clawic/skills) — distributed by [TomeVault](https://tomevault.io).