Compose State Hoisting

Overview

Apply state hoisting and unidirectional data flow to Compose UIs, choosing the right state owner, lifespan, and saving strategy.

For condensed reference and examples, see references/compose-state-guidance.md.

Workflow

1. Identify the state and the logic that reads/writes it.
2. Decide the state owner (lowest common ancestor; or a plain state holder class, or a screen-level state holder like Android ViewModel for complex UI/business logic).
3. Choose the lifespan API (remember/retain/rememberSaveable/rememberSerializable) based on how long it must survive.
4. Make UI composables stateless: pass value and event callbacks; state goes down, events go up.
5. Decide what must be saved and how (rememberSaveable, SavedStateHandle, or platform storage).
6. Verify that state and callbacks are not duplicated or leaked.