Does `HorizontalPager` save/store the next and pre...
# composea
AmrJyniat
12/13/2022, 8:47 AMDoes
HorizontalPagerviewPager2HorizontalPagerviewPager2HorizontalPagerc
czuckie
12/13/2022, 8:54 AMI can't tell you how it works under the hood, though the source code isn't humongous so you could probably look into it yourself, but you'll be hard pressed to find any differences between
ViewPager*HorizontalPagerczuckie
12/13/2022, 8:55 AMI have noticed that it can be a tiny bit janky, but I have only been using the debug builds of my application, so imagine a release build will result in less jank
a
AmrJyniat
12/13/2022, 8:59 AMFor my usecase, each page has a bitmap to load, so it's so unsmooth transition in compare to
viewPagerc
czuckie
12/13/2022, 2:23 PMI think you need to model the state to match what you want a bit more.
If you held the bitmaps outside of the scope of the pager, and simply passed them in, you'd have ultimate control over the lifespan of the bitmaps.
Though, you should be loading the images off the main thread so it shouldn't be janking up your paging.
m
mattinger
12/14/2022, 3:00 AMI have certainly seen this behavior. I have a modifier that fires whenever a composable is first added to a composition and the lifecycle is in the resumed state. If i put this modifier on the pages of a HorizontalPager, it was firing several times. Initially for the 1st and 2nd page. Then if i swipe it along, it would fire for the 3rd page (because the second one was already in the composition, even though it hadn't actually been visible).
mattinger
12/14/2022, 3:02 AMIt makes sense, because under the hood, it's powered by LazyRow or LazyColumn (depending on your orientation), and that also keeps additional items in the composition to allow for smoother scrolling.
And yes, debug builds are dirt slow, so try it with the release build before you assume any jank is related to your code or certain controls.
mattinger
12/14/2022, 3:03 AM109 Views