适用于 KMP 的分层架构
清晰地分离数据层、领域层和展示层
适用于 KMP 的分层架构 是 CoddyKit 上的免费 Kotlin Multiplatform Academy 课时。 这是第 1 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Kotlin Multiplatform Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Kotlin Multiplatform Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
One Codebase, Many Apps
As your KMP app grows, shared code can turn into a tangle. A clear layered architecture keeps every piece in its lane so both apps stay easy to change.
Three Classic Layers
Most KMP apps settle on three layers: data, domain and presentation. Each has one job, and dependencies flow in a single, predictable direction.
The Data Layer
The data layer talks to the outside world: Ktor for HTTP, SQLDelight for storage. It fetches raw bytes and hands clean data upward, hiding the details.
The Domain Layer
The domain layer holds your business rules and models. It knows nothing about HTTP or SQL, so it stays pure, portable and trivially testable.
The Presentation Layer
The presentation layer prepares state for the screen. Shared ViewModels live here, turning domain data into the StateFlow each UI collects.
Dependencies Point Inward
The golden rule: outer layers depend on inner ones, never the reverse. Presentation knows domain; domain knows nothing about either neighbour.
Talk Through Interfaces
Layers connect through interfaces, not concrete classes. Domain declares what it needs; data provides the implementation, so you can swap pieces freely.
interface UserRepository {
suspend fun load(id: String): User
}Models per Layer
Each layer can own its shapes: a network DTO in data, a clean model in domain. Mapping between them keeps API quirks from leaking into your rules.
Why Bother Separating
Separation pays off when requirements shift. Swap a REST API for GraphQL and only the data layer changes; domain and presentation never notice.
It All Lives Shared
Data, domain and presentation can all sit in commonMain. Both Android and iOS reuse the entire stack and only supply the final native screen.
Start Simple
You do not need ten layers on day one. Begin with these three, keep the dependency arrows clean, and let the structure grow only when it earns its keep. 🙂
Quick Check
Which way should dependencies flow between layers?
Recap
You split shared code into data, domain and presentation, pointed dependencies inward, and connected layers through interfaces. Clean lanes, easy changes. 🎉
常见问题解答
「适用于 KMP 的分层架构」课时是免费的吗？
是的 — 「适用于 KMP 的分层架构」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Kotlin Multiplatform Academy 课程的其余内容，请升级到 CoddyKit PRO。 Kotlin Multiplatform Academy 课程共包含 4 节课。
「适用于 KMP 的分层架构」这节课中我会学到什么？
清晰地分离数据层、领域层和展示层 你通过在浏览器中直接运行的动手代码来练习 Kotlin Multiplatform Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Kotlin Multiplatform Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Kotlin Multiplatform Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 1 节课，共 4 节。
「适用于 KMP 的分层架构」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Kotlin Multiplatform Academy 课中编写并运行代码吗？
能。每节 Kotlin Multiplatform Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。
此课程中的所有课时
- 适用于 KMP 的分层架构
- 用例与领域边界
- 将共享代码拆分为模块
- 决定哪些内容保留为原生实现