# Android Architecture

> Expert guidance on setting up and maintaining a modern Android application architecture using Clean Architecture and Hilt. Use this when asked about project structure, module setup, or dependency injection. Use when this capability is needed.

- Skill: `tomevault-io/android-architecture-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/android-architecture-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/android-architecture-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/android-architecture-2

---


# Android Modern Architecture & Modularization

## Instructions

When designing or refactoring an Android application, adhere to the **Guide to App Architecture** and **Clean Architecture** principles.

### 1. High-Level Layers
Structure the application into three primary layers. Dependencies must strictly flow **inwards** (or downwards) to the core logic.

*   **UI Layer (Presentation)**:
    *   **Responsibility**: Displaying data and handling user interactions.
    *   **Components**: Activities, Fragments, Composables, ViewModels.
    *   **Dependencies**: Depends on the Domain Layer (or Data Layer if simple). **Never** depends on the Data Layer implementation details directly.
*   **Domain Layer (Business Logic) [Optional but Recommended]**:
    *   **Responsibility**: Encapsulating complex business rules and reuse.
    *   **Components**: Use Cases (e.g., `GetLatestNewsUseCase`), Domain Models (pure Kotlin data classes).
    *   **Pure Kotlin**: Must NOT contain any Android framework dependencies (no `android.*` imports).
    *   **Dependencies**: Depends on Repository Interfaces.
*   **Data Layer**:
    *   **Responsibility**: Managing application data (fetching, caching, saving).
    *   **Components**: Repositories (implementations), Data Sources (Retrofit APIs, Room DAOs).
    *   **Dependencies**: Depends only on external sources and libraries.

### 2. Dependency Injection with Koin
Use **Koin** for all dependency injection.

`BaseModule` 是 BaseKit 中用于定义 Koin 依赖注入模块的核心文件，主要包含网络请求 (`HttpModule`) 和数据库 (`DBModule`) 的相关配置。

文件路径: `baseKit/src/main/java/me/shetj/base/di/BaseModule.kt`


```kotlin
startKoin {
    androidContext(this@MyApplication)
    modules(getHttpModule(), getDBModule())
}
```

获取实例：

```kotlin
// 在 Activity/Fragment 或其他 Koin Component 中
val apiService: KCApiService by inject()
val saverDao: SaverDao by inject()
```


### 3. Modularization Strategy
For production apps, use a multi-module strategy to improve build times and separation of concerns.

*   **:app**: The main entry point, connects features.
*   **:core:model**: Shared domain models (Pure Kotlin).
*   **:core:data**: Repositories, Data Sources, Database, Network.
*   **:core:domain**: Use Cases and Repository Interfaces.
*   **:core:ui**: Shared Composables, Theme, Resources.
*   **:feature:[name]**: Standalone feature modules containing their own UI and ViewModels. Depends on `:core:domain` and `:core:ui`.

### 4. Checklist for implementation
- [ ] Ensure `Domain` layer has no Android dependencies.
- [ ] Repositories should default to main-safe suspend functions (use `Dispatchers.IO` internally if needed).
- [ ] ViewModels should interact with the UI layer via `StateFlow` (see `android-viewmodel` skill).

---
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<!-- tomevault:4.0:skill_md:2026-04-11 -->