Compose: animations

Core principle

Pick the smallest API that expresses the motion and its lifecycle.

Identify the job: show or hide a subtree, animate one value, coordinate values from one state, resize content, swap content, or handle user-driven motion.
Choose the matching API from the table. Prefer target-state APIs; use Animatable only when gestures, interruption, or imperative control require it.
Check lifecycle: an alpha animation keeps content composed; AnimatedVisibility removes it after exit. Do not use a fade when unmounting is required.
For AnimatedContent, render from the content lambda target and choose a contentKey only when visual identity differs from payload equality. Read AnimatedContent identity for state-holder details.
Keep animated State in layout or draw block modifiers when it changes at frame rate; route deeper diagnosis to Compose performance.
Use Navigation Compose transitions for destination swaps it owns, and dedicated libraries for art-based motion.
Finish when the API, lifecycle, and content identity match the UI, no simpler API fits, and the relevant behavior is verified.