Mavericks mvi

Mavericks MVI Guide

Mavericks screens are rendered from immutable state. Keep state data-only, reducers pure, and side effects in ViewModel methods or UI consumers.

Quick Reference

Task	Use
Define screen state	data class XxxState(...) : MavericksState
Create Hilt VM	@AssistedInject + @Assisted initialState + Factory + hiltMavericksViewModelFactory()
Register VM	@Binds @IntoMap @ViewModelKey in the owning ViewModelModule
One-shot request	suspend { repo.call() }.execute { copy(request = it) }
Long-lived Flow to normal state	flow.setOnEach { value -> copy(value = value) }
Refresh without UI flicker	.execute(retainValue = State::request) { ... }
Compose VM	mavericksViewModel() or mavericksViewModel(argsFactory = { args })
Compose state	vm.collectAsStateWithLifecycle(State::prop)
Fragment VM	by fragmentViewModel() / activityViewModel() / parentFragmentViewModel()
Fragment state	vm.onEach(State::prop) { ... }
Fragment one-shot	vm.onEach(State::effect, deliveryMode = uniqueOnly()) { ... }
Read current state in VM	withState { state -> ... } or suspend awaitState()

Core Rules

• State must be immutable, public, data-only, and reducer-safe.
• Hilt Mavericks VMs must use @AssistedInject, @Assisted initialState, @AssistedFactory, and hiltMavericksViewModelFactory().
• Every Hilt Mavericks VM must be bound with @Binds @IntoMap @ViewModelKey.
• Use execute for finite async work represented by Async<T>.
• Use setOnEach for long-lived Flows that map directly to ordinary State fields.
• Use Mavericks lifecycle-aware Compose collection: com.airbnb.mvrx.compose.collectAsStateWithLifecycle.
• DeliveryMode is only for MavericksView subscriptions, not ViewModel onEach and not Compose.
• Effects are a project pattern on top of State; nullable single effects are not queues.

Read Only What You Need

• State fields, immutability, args, and @PersistState: references/state.md
• ViewModel template, execute, setOnEach, setState, withState: references/viewmodel-execute.md
• Hilt component and map binding: references/hilt.md
• Compose, Fragment, MavericksView, DeliveryMode, scopes: references/observing-ui.md
• Nullable effects, effect queues, consumption rules: references/effects.md
• Async<T> states and rendering patterns: references/async.md
• Mavericks ViewModel testing: references/testing.md

Common Pitfalls

Pitfall	Fix
Missing State defaults with no args path	Add defaults or initialize through args/initialState()
Mutable State field	Use immutable/read-only types and copy on update
Storing derived values	Use computed properties
Reading immediately after setState	Use reducer state, withState, or awaitState()
Heavy work inside reducer	Move work before setState or into execute(dispatcher)
Long action inside VM onEach gets cancelled	onEach uses collectLatest; move long work elsewhere
Flow wrapped in execute when no Async is needed	Use setOnEach
UI flickers during refresh	Use retainValue
Rendering state with uniqueOnly()	Use default delivery mode
Compose using legacy collectAsState	Use Mavericks collectAsStateWithLifecycle
Required Compose args omitted	Use mavericksViewModel(argsFactory = { args })
Effect fires twice after Fragment restart	Use uniqueOnly() and clear after handling
Multiple effects lost	Use a list/queue or redesign event semantics
Hilt VM creation crashes	Check @AssistedFactory, companion factory, and ViewModelModule binding