Flutter Development Guide
A practical guide for building cross-platform applications with Flutter 3 and Dart. Focuses on proven patterns, state management, and performance optimization.
Quick Reference
Widget Patterns
| Purpose | Component |
|---|---|
| State management (simple) | StateProvider + ConsumerWidget |
| State management (complex) | NotifierProvider / Bloc |
| Async data | FutureProvider / AsyncNotifierProvider |
| Real-time streams | StreamProvider |
| Navigation | GoRouter + context.go/push |
| Responsive layout | LayoutBuilder + breakpoints |
| List display | ListView.builder |
| Complex scrolling | CustomScrollView + Slivers |
| Hooks | HookWidget + useState/useEffect |
| Forms | Form + TextFormField + validation |
Performance Patterns
| Purpose | Solution |
|---|---|
| Prevent rebuilds | const constructors |
| Selective updates | ref.watch(provider.select(...)) |
| Isolate repaints | RepaintBoundary |
| Lazy lists | ListView.builder |
| Heavy computation | compute() isolate |
| Image caching | cached_network_image |
Core Principles
Widget Optimization
- Use
constconstructors wherever possible - Extract static widgets to separate const classes
- Use
Keyfor list items (ValueKey, ObjectKey) - Prefer
ConsumerWidgetoverStatefulWidgetfor state
State Management
- Riverpod for dependency injection and simple state
- Bloc/Cubit for event-driven workflows and complex logic
- Never mutate state directly (create new instances)
- Use
select()to minimize rebuilds
Layout
- 8pt spacing increments (8, 16, 24, 32, 48)
- Responsive breakpoints: mobile (<650), tablet (650-1100), desktop (>1100)
- Support all screen sizes with flexible layouts
- Follow Material 3 / Cupertino design guidelines
Performance
- Profile with DevTools before optimizing
- Target <16ms frame time for 60fps
- Use
RepaintBoundaryfor complex animations - Offload heavy work with
compute()
Checklist
Widget Best Practices
- [ ]
constconstructors on all static widgets - [ ] Proper
Keyon list items - [ ]
ConsumerWidgetfor state-dependent widgets - [ ] No widget building inside
build()method - [ ] Extract reusable widgets to separate files
State Management
- [ ] Immutable state objects
- [ ]
select()for granular rebuilds - [ ] Proper provider scoping
- [ ] Dispose controllers and subscriptions
- [ ] Handle loading/error states
Navigation
- [ ] GoRouter with typed routes
- [ ] Auth guards via redirect
- [ ] Deep linking support
- [ ] State preservation across routes
Performance
- [ ] Profile mode testing (
flutter run --profile) - [ ] <16ms frame rendering time
- [ ] No unnecessary rebuilds (DevTools check)
- [ ] Images cached and resized
- [ ] Heavy computation in isolates
Testing
- [ ] Widget tests for UI components
- [ ] Unit tests for business logic
- [ ] Integration tests for user flows
- [ ] Bloc tests with
blocTest()
References
| Topic | Reference |
|---|---|
| Widget patterns, const optimization, responsive layout | Widget Patterns |
| Riverpod providers, notifiers, async state | Riverpod State Management |
| Bloc, Cubit, event-driven state | Bloc State Management |
| GoRouter setup, routes, deep linking | GoRouter Navigation |
| Feature-based structure, dependencies | Project Structure |
| Profiling, const optimization, DevTools | Performance Optimization |
| Widget tests, integration tests, mocking | Testing Strategies |
| iOS/Android/Web specific implementations | Platform Integration |
| Implicit/explicit animations, Hero, transitions | Animations |
| Dio, interceptors, error handling, caching | Networking |
| Form validation, FormField, input formatters | Forms |
| i18n, flutter_localizations, intl | Localization |
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Flutter, Dart, Material Design, and Cupertino are trademarks of Google LLC and Apple Inc. respectively. Riverpod, Bloc, and GoRouter are open-source packages by their respective maintainers.
