IssueTracker

Jetpack Compose release version: beta08
Android Studio Build: Arctic Fox Beta / 4.2 Stable

This is a follow up for https://github.com/google/accompanist/issues/480. Chris Banes suggested that it's a broader problem with Compose, not Pager itself, but the example I prepared is on pager.

The problem is that when we have some heavy layout and low end devices, sometimes frames are skipped ("Choreographer: Skipped 36 frames! The application may be doing too much work on its main thread."). Whenever that happens, the flings are not calculated properly, they are probably finished at the point the frames are skipped.

This didn't happen with the old views, the fling was calculated properly even if there were skipped frames in the middle.

A quick example to reproduce the behavior (I also attached a video where you can see it).

@OptIn(ExperimentalPagerApi::class)
@Composable
fun PagerIssueShowcase(){

    val pagerState = rememberPagerState(pageCount = 50)

    HorizontalPager(
        state = pagerState,
        modifier = Modifier.fillMaxSize()
    ) { pageNo ->
        val childrenCount = if(pageNo % 10 == 0) 2000 else 10
        PotentiallyHeavyLayout(childrenCount)
    }

}

@Composable
fun PotentiallyHeavyLayout(children: Int){

    Column(
        horizontalAlignment = Alignment.CenterHorizontally,
        modifier = Modifier.fillMaxSize().padding(32.dp)
    ) {
        repeat(children) { Text("\uD83E\uDD16") }
    }

}