compose-focus-navigation

Core principle

Focus is stateful UI behavior: make targets and exceptional edges explicit, then drive and verify it through the user's keyboard, D-pad, or remote input.

Procedure

Start with components that already participate in focus. Add a hook only for a requested behavior:

Need	Add
Normal button/text field/clickable focus	Nothing extra; use the focusable component
Programmatic initial/restored focus	`FocusRequester` + `Modifier.focusRequester(...)`
Visual or state reaction to focus changes	`Modifier.onFocusChanged { ... }`
Custom interactive surface that is not already focusable	`Modifier.focusable()` plus role/semantics as appropriate

Request initial or restored focus from LaunchedEffect, keyed to the condition that makes the target present. For lazy content, keep requesters by stable item id and request only after the item is composed. Inside AnimatedContent, use the content lambda's target consistently for rendered identity, tags, requester ownership, and the effect key; captured outer state gives outgoing and incoming content the same identity.
Keep default spatial search unless a concrete edge, jump, or trap is wrong. Encode only those exceptions with focusProperties.
Handle keys only for behavior that is not normal click or traversal. Consume exactly the handled event; throttle rapid D-pad work at its expensive owner, not across the screen.
Restore by semantic identity after refresh: retain the focused id when it exists, otherwise choose a deterministic fallback.
Test with one concrete key/D-pad interaction and focused semantics. When the behavior under review is user-triggered, do not substitute direct state mutation or leave the input conditional. Use screenshots only for the focus appearance.
Finish when all intentional targets and exceptional edges are encoded, loading/refresh behavior has a stable focus policy, and tests use the same input model as users.

For example, request and observe focus only when both behaviors are required:

val requester = remember { FocusRequester() }
 
Button(
    onClick = onClick,
    modifier =

Call focus requests from an effect, not the composable body:

If the target appears after loading, key the request to the condition:

Use focusProperties only when default spatial search is wrong:

Too many hard-coded links create stale focus graphs. For special key behavior, consume only the handled event:

Test focus through user input:

Broader test-shape choices are in Compose UI testing patterns.