android-state

name

android-state

description

Standards for ViewModel, StateFlow, and UI State Patterns. Use whenever someone works with ViewModel files, asks about UiState sealed classes, MutableStateFlow vs LiveData, collectAsStateWithLifecycle, viewModelScope, or exposing state from Android ViewModels — even indirectly. (triggers: **/*ViewModel.kt, **/*UiState.kt, viewmodel, stateflow, livedata, uistate, MutableStateFlow, collectAsState, viewModelScope, UiState)

Android State Management

Priority: P0

Implementation Guidelines

ViewModel Pattern

• Exposure: Expose ONE StateFlow<UiState> via .asStateFlow().
• Scope: Use viewModelScope for all coroutines.
• Initialization: Trigger initial load in init or LaunchedEffect (once).

UI State (LCE)

• Type: sealed interface UiState (Loading, Content, Error).
• Immutability: Data classes inside should be @Immutable.

Flow Lifecycle

• Collection: Use collectAsStateWithLifecycle() in Compose.
• Hot Flows: 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.

References

• Templates