Flutter

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