flutter-app-architecture

# Flutter App Architecture Skill This skill defines how to structure Flutter applications using layered architecture, proper data flow, and MVVM patterns for maintainability and testability. ## When to Use Use this skill when: * Scaffolding a new Flutter project with layered architecture. * Creating or refactoring View Models, Repositories, or Services. * Wiring dependency injection between architectural components. * Implementing unidirectional data flow across layers. * Adding a Domain (Logic) Layer for complex business logic or shared use cases. --- ## 1. Layer Structure Separate every app into a **UI Layer** and a **Data Layer**. Add a **Logic (Domain) Layer** only for complex apps. ``` ┌──────────────────────────────────────────────────────────────┐ │ UI Layer │ Views + ViewModels │ ├──────────────────────────────────────────────────────────────┤ │ Logic Layer │ Use Cases / Interactors (optional) │ ├──────────────────────────────────────────────────────────────┤ │ Data Layer │ Repositories + Services │ └──────────────────────────────────────────────────────────────┘ ``` **Rules:** - Only adjacent layers may communicate. The UI layer must never access a Service directly. - Data changes always happen in the Data layer (SSOT = Repository). No mutation in UI or Logic layers. - Follow unidirectional data flow: state flows **down** (Data → UI), events flow **up** (UI → Data). --- ## 2. Component Res...