What s the canonical way of automatically giving focus to an kotlinlang #compose

What’s the canonical way of automatically giving focus to an element that enters the composition within the same frame? I saw several examples online that suggest using a

FocusRequester

within a

LaunchedEffect

but I am worried that this would not reliably happen within the same frame because the coroutine behind

LaunchedEffect

might be scheduled too late?

Loney Chou

05/08/2023, 8:46 AM

May I ask what frame are you referring to? Like, same frame with what.

Anyway, the only way to manually request focus on a specific component is by using

FocusRequester

Modifier.focusRequester

FocusRequesterModifierNode

(experimental), and most of the time you would use the former. A FocusRequester needs to know where it is in order to search for a focusable target, and this is done during the composition phase (when updating the

modifier

of a

LayoutNode

). Considering not causing any weird issue, using

XxxEffect

should be the safest and fastest way, because they get executed right after the composition is ready (if I remember correctly).

You may use

DisposableEffect

for it right. It gets executed on the spot, unlike

LaunchedEffect

which will somehow "schedule" the execution, it depends.

Manuel Unterhofer

05/08/2023, 9:25 AM

Frame as in update of the UI, one update cycle that the user will see.

Ah, I forgot that

DisposableEffect

has keys. That should solve it, thanks!

Zach Klippenstein (he/him) [MOD]

05/15/2023, 11:19 PM

LaunchedEffect

should work as well. The coroutines are scheduled at the same time as `DisposableEffect`s are ran, and so they will always be dispatched before the next frame’s input handling phase (which is the first thing the choreographer does)

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