Flutter

Flutter/Dart Best Practices

Widget Composition

• Build UI from small, composable widgets; each widget should do one thing well
• Use const constructors wherever possible -- enables compile-time optimizations and faster rebuilds
• Prefer stateless widgets; only use StatefulWidget when the widget manages mutable state
• Apply the Widget composition pattern: container widgets handle state, leaf widgets are purely presentational
• Extract repeated UI patterns into reusable widgets in a widgets/ or components/ directory

State Management

• Use Riverpod as the primary state management solution: Provider for dependencies, Notifier for state
• Define providers at the top level; use ref.watch in widgets and ref.read in callbacks
• Use AsyncValue for loading/error/data state handling: when(loading:, error:, data:)
• For BLoC pattern: define events, states, and blocs; use BlocBuilder, BlocListener, BlocConsumer in UI
• Keep state immutable; create new state instances on change rather than mutating in place

Platform Channels

• Use MethodChannel for calling platform-specific APIs from Dart to native (Kotlin/Swift)
• Use EventChannel for streaming platform events to Dart: sensor data, connectivity changes
• Register channels in MainActivity (Android) and AppDelegate (iOS) with matching channel names
• Use Pigeon for type-safe platform channel code generation instead of manual serialization
• Keep platform-specific code minimal; push as much logic as possible into the shared Dart layer

Responsive Layout

• Use MediaQuery for screen-size-dependent layouts; LayoutBuilder for parent-constrained layouts
• Apply Flexible and Expanded within Row/Column for proportional sizing
• Use SingleChildScrollView with ConstrainedBox for scrollable forms; avoid unbounded heights
• Define breakpoints in a constants file: mobile (<600), tablet (600-1200), desktop (>1200)
• Test layouts with DevicePreview package across screen sizes before physical device testing

Testing

• Write widget tests with testWidgets: pump the widget, find elements, verify behavior
• Use mockito or mocktail for mocking dependencies in unit tests
• Create golden tests for critical UI components: matchesGoldenFile('goldens/widget.png')
• Run flutter test --coverage in CI; enforce minimum coverage thresholds for core logic
• Integration tests in integration_test/ use IntegrationTestWidgetsFlutterBinding for device testing

Source: calcosmic/Aether — distributed by TomeVault.