I'm trying to pinpoint performance issues (laggy LazyColumn). I'm testing that on release+R8 (on Huawei P20 lite Android 9), but it's still not good. I don't really understand what kind of difference should I expect between release+R8 on development machine and google play version and wanted to try to simulate that. Found:

adb shell cmd package compile -r bg-dexopt my.app.id

But it only shows me

Failure: package my.app.id could not be compiled

My second question is - can I somehow test the final experience, e.g. should deploying to Firebase App Distribution work as fine as Google Play or not really?

I have a problem with

Flow.collectAsState()

where collection of the flow starts one frame after initial composition. Usually my

Flow

emits its first value immediately upon subscription, and in that case I don’t want to see

initialValue

. But because collect starts only after first frame, there’s visible fast “blink” when you first open a screen. As I understand it’s because

LaunchedEffect

executes it’s lambda in

AndroidUiDispatcher

, and it dispatches `LaunchedEffect`’s job only after first frame has been drawn. I found a solution, where if I launch a coroutine that collects the

Flow

with

start = CoroutineStart.UNDISPATCHED

, value is produced immediately after first composition (so I can read it inside

SubcomposeLayout

of some sort, and screen does not “blink”). Is there any pitfalls of doing so?

Where should I start digging when looking to optimize a large/complex screen that stutters? 🧵👀

Is there a way to not strip out @Preview composables for a build that has

isMinifyEnabled = true

? Couldn’t find how to edit my proguard to make that happen My use case is that I want a different build type, that is not production, but is used to test the production experience (minified) but also be able to browse the previews rendered by Showkase

would it be a bad idea, to have a CompositionLocalProvider for a callback, to communicate with root composable, like post msg on a msg bus?

Hey all, I've got a

BottomSheet

that sits above the

BottomAppBar

. As the sheet is expanded, I'd like the

BottomAppBar

to scroll off screen. I've managed to sort of achieve this by tying the `BottomAppBar's`y offset to the bottom sheet's offset amount (derived from

BottomSheetState

direction & progress:

val bottomSheetScaffoldState = rememberBottomSheetScaffoldState()

Scaffold (
    bottomBar = {
        BottomAppBar(Modifier.offset(y = 56.dp * (1f - bottomSheetState.offsetFraction()))
    }
) { padding ->
    BottomSheetScaffold(Modifier.padding(bottom = 56.dp * bottomSheetState.offsetFraction()))
}

The problem is that the bottom sheet scroll/fling events now seem to be sort of interrupted. I guess having the padding change out from underneath it while it's scrolling causes issues with the size calculations or something along those lines. Just wondering if anyone can recommend an approach for this?

how to listen to onbackpressed in jetpack compose

Hi, I've just switched to acompanist navigation animation, and iam having the folowing error when I try to add the args to the

composable()

, removing the arguments makes evething works fine.

Navigation destination that matches request NavDeepLinkRequest{ uri=<android-app://androidx.navigation/character> } cannot be found in the navigation graph NavGraph(0x0) startDestination={NavGraph(0x78da56c6) route=main startDestination={Destination(0x78d845ec) route=home}}

This is the code thats braking

composable(
            route = MainRoutes.CharacterDetail.routeName,
           arguments = MainRoutes.CharacterDetail.navArgs, /*Comenting this line get things working again*/
            enterTransition = {initial, target -> null },
            exitTransition = {initial, target -> null },
            popEnterTransition = {initial, target -> null },
            popExitTransition = {initial, target -> null }

        ) { backStackEntry ->
            val character = MainRoutes.CharacterDetail.getNavArgs(backStackEntry)
            character?.let {
                CharacterScreen(
                    character = character,
                    onBack = { navController.popBackStack() })
            }
        }

Would anyone giving me a hint about this snippet code in 🧵 Context:

mutableStateOf(<with initial/default value>)

but the recomposition unable to use the default value

Considering:

Column(modifier = Modifier.height(128.dp)) {
    Text("Super long text...", overflow = TextOverflow.Ellipsis)
}

Is there a way to constraint the Text to ellipsize as soon as the next line would be outside the column? Since the column has a predefined height, different font scales would require different max lines. I know I can check

LocalDensity.current.fontScale

but I'm looking for something more generic

HI, just had a presentation on compose in my company and the QAs asked will compose still work with their automation frameworks. Anyone have any comments?

Just noticed that the alpha version of Compose enforces a minCompileSdk of 31. Do we know if the stable version of Compose is also going to enforce this soon (my guess is that it probably will). The main reason we were trying to use alpha was because we wanted to leverage Kotlin 1.5.30.

Matrix code created in Compose

ETA of a stable Compose release with KT 1.5.30?

When I'm hooking up the

up

button, I know that both

navController.navigateUp()
and
navController.popBackStack()

do the same thing, but which one should be used for the up action specifically.

navigateUp

right?

I was asked if I could display photos in the gallery of my app in the way Lightroom CC or Mylio do with their "fluid grid style". I don't see any support for that in Compose. Does someone know a library that has this kind of grid style already?

I need to popBackStack() to a specific screen that contains Scaffold bottom navigation. Depending on the situation, sometimes it takes two popBackStack's sometimes one to get to the screen. Is there any better way to handle returning to the bottom navigation screen and still keep the bottom navigation state in a situation where I am not sure how many popBackStacks are required?

Is it possible to make a similar layout as below using LazyColumn in jetpack compose? Inner List is not scrollable.

What’s the best way to handling an infinite paging list without using the jetpack paging library? (Trying to keep my paging solution JVM only for easier testing and hopefully KMP at some point) I’m currently using

SnapshotStateList

and it’s working fine but still new to Compose so was wondering if anyone had a better implementation.

I want to scroll a

LazyRow

so that the element is centered.

LazyListState.animateScrollToItem()

takes an

index

and a

scrollOffset

as arguments. Per default it scrolls the list so that the item is the first one. If a positive

scrollOffset

is given it scrolls further, making the item go off scren. So I tried to give a negative

scrollOffset

and calculate what I need so that the element is in center position. The problem is: Negative Offsets are not allowed. 😞 How can I scroll to an index that it's at the center of the list?

🧪 How do I see the

println

or

Log

output in androidTest? Details in thread 🧵

How can I get the center of any composable element? I was trying using

onGloballyPositioned{..}

(I also have some other code and I want to avoid adding it this modifier since it’s called a lot.) Is there any method/modifier where I can get any alternative of `Rect`/

bounds

?

Hi all, is there a performance issue when we embed Scaffold? For example the first Scaffold has a bottom bar and each page has a Scaffold Content. Which means, instead of defining TopAppBar from the parent and change depending on the route, each child will have it’s one Scaffold therefore it own TopAppbar

Is it possible to turn off default fade transition animation?

Hello here! I'm playing with

Text

composable, the callback

onTextLayout

to get information about text measurements and the modifier

drawBehind

.

Text(
    text = "My text here\n Multi line",
    modifier = Modifier.drawBehind {
        // Draw something here
    },
    onTextLayout = { textLayoutResult ->
        // Get value of textLayoutResult.multiParagraph.lineCount 
        // Get values of textLayoutResult.multiParagraph.getLineHeight(index)
    }
)

If I'm using this snippet with two states, it works well but my composable is draw 2 times. First time to measure the text and the second time when my states are updated inside the

onTextLayout

callback which force a new recomposition. I would like to know if it is possible to avoid to draw 2 times my text when there are no changes between my first and second composition? If anyone have an idea, I'm very interested! Thanks!

am introducing

compose

into new project but I can’t run it. error:

org.jetbrains.kotlin.backend.common.BackendException: Backend Internal error: Exception during IR lowering

I have fragment with

ComposeView

and am just calling

setContent

on it any help? compose version 1.0.2 compose build feature is enabled

composeOptions {
    kotlinCompilerExtensionVersion = "1.0.2"
    kotlinCompilerVersion = "1.5.21"
}

I have a horizontal pager with two images that isn't working how I expect it would. Anyone have any ideas? Code in thread.

When I click on a bottom

BasicTextField

, the keyboard covers the input. Is this expected behavior (even with

adjustResize

)?

LazyColumn {
  items((1..100).toList()) { BasicTextField("$it", {}) }
}

Has anyone had any issues with the Paging 3.0 Library duplicating data? Every time a new page is requested, it loads the new data but then overwrites all of the previous data with the new data. See code in thread: