What is the standard way to organize Android code in project

Organizing Android Code: Best Practices

Structuring your Android project code effectively is crucial for maintainability, scalability, and ease of development. This article outlines the standard approach to organize your Android project, emphasizing best practices.

Project Structure

1. Core Modules

The project is typically divided into core modules, each representing a distinct part of your application. Common modules include:

• App Module: Contains the main application logic, manifest, and entry point (usually the MainActivity).
• UI Module: Houses all user interface elements (layouts, Activities, Fragments, etc.).
• Data Module: Manages data persistence, networking, and interactions with databases (Room, SQLite, etc.).
• Domain Module: Encapsulates business logic, use cases, and data models, independent of UI or persistence details.

2. Package Structure Within Modules

Within each module, you’ll organize your code into packages. This structure aids in code discoverability and promotes modularity.

Example Package Structure

└── app
    └── src
        └── main
            └── java
                └── com
                    └── example
                        └── myapp
                            ├── data
                            │   ├── local
                            │   │   ├── db
                            │   │   └── dao
                            │   └── remote
                            │       ├── api
                            │       └── models
                            ├── domain
                            │   └── usecases
                            └── ui
                                └── activities
                                    └── MainActivity.java

3. Directory Structure

The project also uses a directory structure for resource files, assets, and other elements:

• res: Holds resources like layouts, drawables, strings, etc.
• assets: Contains raw assets that can be loaded at runtime.
• AndroidManifest.xml: Defines the application components, permissions, and other metadata.
• build.gradle (Module): Defines dependencies, build configurations, and other module-specific settings.
• build.gradle (Project): Defines project-level settings, including dependencies and build options.

Best Practices for Organizing Android Code

Following these best practices ensures a well-structured and maintainable Android project.

1. Single Responsibility Principle (SRP)

Each class, module, or package should have a single, well-defined responsibility. This promotes reusability and easier maintenance.

2. SOLID Principles

Adhering to SOLID principles (Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, Dependency Inversion) helps you write robust, adaptable code.

3. Dependency Injection

Use dependency injection frameworks (like Dagger 2 or Hilt) to manage dependencies effectively, enhancing testability and code modularity.

4. Code Style Guidelines

Follow the official Android code style guidelines for consistency, readability, and uniformity.

Code Example: Data Module

└── app
    └── src
        └── main
            └── java
                └── com
                    └── example
                        └── myapp
                            └── data
                                ├── local
                                │   ├── db
                                │   │   └── AppDatabase.java
                                │   └── dao
                                │       └── UserDAO.java
                                └── remote
                                    ├── api
                                    │   └── UserApi.java
                                    └── models
                                        └── User.java

Data Model (User.java)

package com.example.myapp.data.remote.models;

public class User {
    private String name;
    private String email;
    // ... other properties
}

Remote API Interface (UserApi.java)

package com.example.myapp.data.remote.api;

import com.example.myapp.data.remote.models.User;

import retrofit2.Call;
import retrofit2.http.GET;

public interface UserApi {
    @GET("users")
    Call<List<User>> getUsers();
}

Table: Advantages of Structured Code

By adopting these principles and following a consistent organization structure, you can create well-structured and maintainable Android projects.