cursorrules

Android AI Skills — Cursor (Legacy Format)

Drop this file as .cursorrules in your Android project root.

For the modern .mdc format with per-file activation, see cursor/rules/

Source: https://github.com/RanaNadeemAslam/android-ai-skills

You are a senior Android developer. Follow these rules strictly when writing or modifying Android/Kotlin code.

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Architecture

Official source: https://developer.android.com/topic/architecture

Follow Google's official app architecture guidance strictly. Every architectural decision must prioritize testability, separation of concerns, and unidirectional data flow.

Layered Architecture

Follow the recommended layered architecture: UI Layer -> Domain Layer (optional) -> Data Layer.

DO:

• Separate the app into UI, Domain (optional), and Data layers
• Each layer should only depend on the layer directly below it
• UI layer never accesses data sources directly — always through a repository
• Domain layer is optional — only add it when multiple ViewModels share business logic

DON'T:

• Let UI layer call data sources, APIs, or DAOs directly
• Let Data layer reference UI or ViewModel classes
• Create circular dependencies between layers
• Add a Domain layer "just in case" — add it when you need it

UI Layer (Compose + ViewModel)
       ↕
Domain Layer (UseCases) — optional
       ↕
Data Layer (Repositories + DataSources)

Source: https://developer.android.com/topic/architecture#recommended-app-arch

UI Layer & State Management

Source: https://developer.android.com/topic/architecture/ui-layer

DO:

• Model UI state as a single immutable data class per screen:

data class ProfileUiState(
    val isLoading: Boolean = false,
    val profile: Profile? = null,
    val errorMessage: String? = null,
)

• Or use a sealed interface when states are mutually exclusive:

sealed interface ProfileUiState {
    data object Loading : ProfileUiState
    data class Success(val profile: Profile) : ProfileUiState
    data class Error(val message: String) : ProfileUiState
}

• Expose UI state from ViewModel as StateFlow:

private val _uiState = MutableStateFlow(ProfileUiState())
val uiState: StateFlow<ProfileUiState> = _uiState.asStateFlow()

• Collect state in Compose with collectAsStateWithLifecycle():

val uiState by viewModel.uiState.collectAsStateWithLifecycle()

• Model user actions as events/intents passed to ViewModel via function calls