User List App

A Flutter application demonstrating clean architecture, SOLID principles, and best practices in mobile app development.

Project Overview

The User List App is a demonstration of how to build a scalable and maintainable Flutter application. It implements a simple user management system with features to view, add, and delete users while showcasing various software engineering principles and best practices.

Architecture

The project follows Clean Architecture principles, divided into three main layers:

1. Domain Layer

• Contains business logic and rules
• Defines entities and repository interfaces
• Houses use cases that encapsulate business operations
• Independent of any external frameworks

2. Data Layer

• Implements repository interfaces
• Handles data operations and transformations
• Manages local storage through data sources
• Implements caching mechanisms

3. Presentation Layer

• Contains UI components and controllers
• Manages state and user interactions
• Implements the user interface using Flutter widgets

SOLID Principles Implementation

Single Responsibility Principle (SRP)

• Each use case handles one specific operation (GetUsers, AddUser, DeleteUser)
• Repository implementation focuses solely on data operations
• Controllers are responsible only for UI state management
• Data sources handle only storage operations

Open/Closed Principle (OCP)

• Repository interfaces allow new implementations without modifying existing code
• Use cases can be extended without changing existing ones
• Failure handling system is extensible with new failure types

Liskov Substitution Principle (LSP)

• Repository implementations properly substitute their interfaces
• Models extend entities without breaking behavior
• All implementations can be substituted with their base types

Interface Segregation Principle (ISP)

• Repository interfaces are focused and minimal
• Use cases have specific interfaces for their needs
• Data source interfaces include only necessary methods

Dependency Inversion Principle (DIP)

• High-level modules depend on abstractions
• Low-level modules implement abstractions
• Dependencies are injected through constructors
• Dependency injection container manages object creation

Best Practices

Error Handling

• Consistent use of Either type for error handling
• Well-defined failure types
• Descriptive error messages with context
• Proper error propagation through layers

Testing

• Comprehensive unit tests
• Mock objects for testing
• Test coverage monitoring
• Testable architecture design

Code Organization

• Feature-based folder structure
• Clear separation of concerns
• Consistent naming conventions
• Clean and maintainable code

State Management

• Centralized state management
• Predictable state updates
• Clear state transitions
• Efficient UI updates

Dependency Management

• Proper dependency injection
• Clear dependency graph
• Manageable dependencies
• Easy dependency updates

Project Structure

lib/
├── core/
│   ├── base/
│   │   ├── base_state.dart
│   │   └── base_view_model.dart
│   ├── error/
│   │   └── failures.dart
│   ├── usecase/
│   │   └── usecase.dart
│   └── config/
│       └── environment.dart
├── features/
│   └── user_list/
│       ├── data/
│       │   ├── datasources/
│       │   ├── models/
│       │   └── repositories/
│       ├── domain/
│       │   ├── entities/
│       │   ├── repositories/
│       │   └── usecases/
│       └── presentation/
│           ├── controllers/
│           ├── pages/
│           └── state/
└── injection_container.dart

Getting Started

1. Clone the repository
2. Run flutter pub get to install dependencies
3. Run flutter test to execute tests
4. Run flutter run to start the application

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.