/android-state

name: android-state
description: Configure ViewModel state emission with StateFlow, SharedFlow, and sealed UiState classes in Android. Use for state modeling and sharing policies; defer generic lifecycle collection, navigation-event plumbing, Hilt injection, test code, and configuration-change recipes to their specific skills.
metadata:
  triggers:
    files:
    - '**/*ViewModel.kt'
    - '**/*UiState.kt'
    keywords:
    - viewmodel
    - stateflow
    - livedata
    - uistate
    - MutableStateFlow
    - collectAsState
    - viewModelScope
    - UiState

Android State Management

**Priority: P0 (CRITICAL)**

1. Structure ViewModel

• Expose ONE `StateFlow<UiState>` via `.asStateFlow()`.
• Use `viewModelScope` for all coroutines.
• Trigger initial load in `init` block.

See [templates](references/implementation.md) for ViewModel and UiState examples.

2. Define UI State (LCE Pattern)

• Use sealed interface with Loading, Content, Error variants.
• Mark data classes `@Immutable`.

See [templates](references/implementation.md) for sealed UiState pattern.

3. Collect State Lifecycle-Safely

• Use `collectAsStateWithLifecycle()` in Compose.
• Use `SharingStarted.WhileSubscribed(5000)` for shared resources.

Anti-Patterns

• **No LiveData for New Code**: Use StateFlow — lifecycle-safe and Compose-compatible.
• **No Public MutableStateFlow**: Expose only `.asStateFlow()` to consumers.
• **No Context in ViewModel**: Leaks Activity. Use Application context if truly needed.

Verification

• [ ] Each ViewModel exposes exactly one `StateFlow<UiState>`.
• [ ] UiState is a sealed interface with Loading, Content, Error variants.
• [ ] UI collects with `collectAsStateWithLifecycle()`.
• [ ] `./gradlew test` passes for ViewModel tests.

References

• [Templates](references/implementation.md)