version: "1.0.0" name: flutter-dev description: | Flutter cross-platform development guide covering widget patterns, Riverpod/Bloc state management, GoRouter navigation, performance optimization, and platform-specific implementations. Includes const optimization, responsive layouts, testing strategies, and DevTools profiling. Use when: building Flutter apps, implementing state management (Riverpod/Bloc), setting up GoRouter navigation, creating custom widgets, optimizing performance, writing widget tests, cross-platform development. description_zh: "Flutter 跨平台开发指南" description_en: "Flutter cross-platform dev guide (Riverpod, GoRouter)" license: MIT metadata: version: "1.0.0" category: mobile sources:

• Flutter Documentation
• Riverpod Documentation
• Bloc Library Documentation

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

Performance Patterns

Core Principles

Widget Optimization

• Use const constructors wherever possible
• Extract static widgets to separate const classes
• Use Key for list items (ValueKey, ObjectKey)
• Prefer ConsumerWidget over StatefulWidget for 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 RepaintBoundary for complex animations
• Offload heavy work with compute()

Checklist

Widget Best Practices

• [ ] const constructors on all static widgets
• [ ] Proper Key on list items
• [ ] ConsumerWidget for 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

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.