LazyColumn is slower than Column with vertical scroll

Question

I have product cell which I want to display on the list, I've used LazyColumn but performance was terrible, I couldn't find why it is so slow. Then I've switched LazyColumn to Column and all of the sudden scrolling is super smooth

LazyColumn version:

LazyColumn() {
    items(cartItems, key = {it.cartItem.id}) { cartItemData ->
        CartItemWithActions(data = cartItemData)
        Divider(color = colorResource(id = R.color.separator_line))
    }
}

Column version

val state = rememberScrollState()
Column(modifier = Modifier.verticalScroll(state)) {
    cartItems.forEach { cartItemData ->
        CartItemWithActions(data = cartItemData)
        Divider(color = colorResource(id = R.color.separator_line))
    }
}

CartItemWithActions is my product cell with image that I'm loading using glide and couple of texts

HWUI for LazyColumn version

HWUI for Column

Can anyone provide hint why LazyColumn is slower than Column?

UPDATE

It seems LazyColumn scroll much better when LazyColumn is setup this way

LazyColumn() {
    items(
        count = cartItems.size,
        key = {
            cartItems[it].cartItem.id
        },
        itemContent = { index ->
            val cartItemData = cartItems[index]
            CartItemWithActions(data = cartItemData)
            Divider(
                color = colorResource(id =R.color.separator_line)
            )
        }
    )
}

I've personally experience it too, but it seemed to go away after you scroll randomly for five seconds continuously, upon every app startup — Richard Onslow Roper, Nov 05 '21 at 16:37
This doesn't happen with simple stuff like `Text`, but with heavy custom Composables, this did seem like an issue to me as well. — Richard Onslow Roper, Nov 05 '21 at 16:38
I thought it would go away in the release build and so I ignored it. — Richard Onslow Roper, Nov 05 '21 at 16:40
@PhilipDukhov I've added more details, but since it's contains many references to other functions it's hard to include all of it here — Maciej Przybylski, Nov 05 '21 at 16:45
@Francesc, thx I will do that, however even without alpha it's the same — Maciej Przybylski, Nov 05 '21 at 16:46
Hey can we celebrate it? It is exactly the 2500th question on the `android-jetpack-compose` tag! — Richard Onslow Roper, Nov 05 '21 at 18:17
@PhilipDukhov WebImage is using glide to load image, commenting it out makes no difference — Maciej Przybylski, Nov 05 '21 at 22:25
I've added HWUI render profile for both versions, it seems like LazyColumn takes much more time to layout elements than for Column version — Maciej Przybylski, Nov 05 '21 at 22:33
@MaciejPrzybylski try commenting out all children one by one to see find the one which is causing the troubles — Phil Dukhov, Nov 06 '21 at 08:52
@PhilipDukhov I've tried that in the first place but I cant't find what is causing it. as soon as I put something more than Text it starts to lag — Maciej Przybylski, Nov 06 '21 at 14:14

score 8 · Accepted Answer · answered Nov 06 '21 at 18:12

8

It seems that initialising LazyColumn in this way solves my issue

LazyColumn() {
    items(
        count = cartItems.size,
        key = {
            cartItems[it].cartItem.id
        },
        itemContent = { index ->
            val cartItemData = cartItems[index]
            CartItemWithActions(data = cartItemData)
            Divider(
                color = colorResource(id =R.color.separator_line)
            )
        }
    )
}

However I still don't know why

answered Nov 06 '21 at 18:12

Maciej Przybylski

359
2
11

1

It works better because using the key parameter gives Jetpack Compose a similar power to DiffUtil in RecyclerView. – Mattia Ferigutti Jan 08 '22 at 16:58
6

doesn't work with compose 1.2.0. same sluggish behaviour – isudansh Aug 04 '22 at 14:20
1

@isudansh same with me. – thebluepandabear Sep 23 '22 at 09:17
2

Is sluggish behaviour resolved now ? – Jeff Bootsholz Dec 29 '22 at 07:00
3

I still see laggy behavior. – HBB20 Dec 29 '22 at 17:01
@HBB20 I have the same issue. LazyColumn is extremely laggy. Is this related to compose version? does downgrading the version work? – mrzbn Feb 07 '23 at 06:37

score 3 · Answer 2 · answered Jan 02 '23 at 01:45

3

Yes so weird noone talking about this s. Normal column like 5x faster and smooth than lazy column. Problem is when loading data in normal column freezing screen like 2 second for 50 card but after 0 freezing or slowing etc.

answered Jan 02 '23 at 01:45

Nick

73
7

This does not really answer the question. If you have a different question, you can ask it by clicking [Ask Question](https://stackoverflow.com/questions/ask). To get notified when this question gets new answers, you can [follow this question](https://meta.stackexchange.com/q/345661). Once you have enough [reputation](https://stackoverflow.com/help/whats-reputation), you can also [add a bounty](https://stackoverflow.com/help/privileges/set-bounties) to draw more attention to this question. - [From Review](/review/late-answers/33538443) – Saurabh Bhandari Jan 03 '23 at 07:39

LazyColumn is slower than Column with vertical scroll

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