仓库模式
清晰地协调不同数据源。
仓库模式 是 CoddyKit 上的免费 Jetpack Compose Academy 课时。 这是第 3 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 Jetpack Compose Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Jetpack Compose 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。
Hide the Data Details
Your ViewModel should not know about DAOs or networks. A repository hides those details behind a clean, simple interface.
A Single Doorway to Data
The repository is the one place the rest of the app asks for data, whether it comes from Room, the network, or memory.
Wrap the DAO
Give the repository the DAO and let it expose friendly methods. Callers see notes, not SQL queries.
class NoteRepository(private val dao: NoteDao) {
val notes = dao.observeAll()
}Expose Actions, Not Tables
Add purposeful functions like addNote. The name says what happens; the storage mechanism stays hidden inside.
suspend fun addNote(text: String) = dao.insert(Note(text = text))Swap Sources Freely
Because callers depend on the repository, you can switch from Room to a fake or a remote API without touching the ViewModel.
Easier to Test
Tests can pass a fake repository to the ViewModel, so you verify logic without a real database on disk. ✅
class FakeRepo : NoteRepository { /* in-memory */ }Inject the Repository
The ViewModel receives the repository through its constructor, never creating it directly. That keeps dependencies explicit.
class NoteViewModel(private val repo: NoteRepository) : ViewModel()Combine Multiple Sources
A repository can merge cache and network, deciding what to return. The UI just asks once and stays unaware of the plumbing.
Pass Flows Straight Through
For reactive data the repository can simply forward the DAO Flow, adding transformations only when the app actually needs them.
val notes: Flow<List<Note>> = dao.observeAll()One Repository per Domain
Keep repositories focused: one for notes, one for users. Each owns a single area of data and its sources.
Clean Layers, Clear Roles
UI shows data, ViewModel holds state, repository fetches it, Room stores it. Each layer has one job and stays replaceable.
Quick Check
What is the main job of a repository in this architecture?
Recap: A Clean Middle Layer
You put a repository between the ViewModel and your data, exposing actions and Flows while hiding the source. Next you will make it work offline first.
常见问题解答
「仓库模式」课时是免费的吗？
是的 — 「仓库模式」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 Jetpack Compose Academy 课程的其余内容，请升级到 CoddyKit PRO。 Jetpack Compose Academy 课程共包含 4 节课。
「仓库模式」这节课中我会学到什么？
清晰地协调不同数据源。 你通过在浏览器中直接运行的动手代码来练习 Jetpack Compose 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 Jetpack Compose Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Jetpack Compose 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 3 节课，共 4 节。
「仓库模式」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 Jetpack Compose Academy 课中编写并运行代码吗？
能。每节 Jetpack Compose 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。