For a component like Accompanist HorizontalPager, the docs state

Pages in both

HorizontalPager

and

VerticalPager

are lazily composed and laid-out as required by the layout. As the user scrolls through pages, any pages which are no longer required are removed from the content.

Does this mean it is safe to use LaunchedEffect as a signal that the current page is just been shown? Or do they get created eagerly when user is contemplating a scroll/starting a swipe? Should pager state change events be used instead?

A

LaunchedEffect

reading what state? But yes, just use the

PagerState.currentPage

, it's what it is there for

Thanks, that's perfect. It's actually going to be a DisposableEffect, needs to set up an event listener when the page goes on screen, and removes it when it leaves, replaced by handler in UI on another page. So sounds like I've introduced a bug using anything triggered on Composition, rather than the currentPage.

Note that `LaunchedEffect`/`DisposableEffect` won't work as you expected in a lazy list. As Chris suggested,

currentPage

is what you should use. See this.