Is anyone using

rememberLauncherForActivityResult

and Compose Navigation?

How can I invert the luminance component of a

Color

? (by invert I mean doing 1-x, in other words if luminance is 0.75 inverting it yields a luminance of 0.25). I’ve tried something like this but with little success:

val xyz = myColor.convert(ColorSpaces.CieXyz)
val invertedLuminance = xyz.copy(green = 1 - xyz.green)
val result = invertedLuminance.convert(ColorSpaces.Srgb)

Hi all! So far, Compose versions have been tied to Kotlin version/vice-versa until Kotlin makes compiler plugin APIs stable. Is this still true, or have there been any recent developments on this front? 🙏🏼

Hi is it possible to let Composables "react" differently on keyboard-state (hidden/shown). In my case I want to keep a button row at the bottom below keyboard and move the rest of the screen above but I'm not sure if that's even possible. 🤔

RecyclerView - ComposeView as view holder Not sure why the screen is not recomposed consistently during orientation change. When the device is rotated to landscape mode the screen sometimes displays the same width as in portrait mode for the recycler view. This does not happen all the time.

This doc seems outdated as

AnimatedVisibility

is not experimental anymore

Hello, I have created a column with vertical scroll enabled, which has 5 rows having horizontal scroll enabled. Sometimes when I scroll over them very fast vertically, rows consume the swipe gesture and don't scroll and appear like the application is lagging. can someone guide me on how I can only enable row scrolling till some

x

amount of horizontal scroll has happened.

After updating compose to 1.2 06 alpha to get the font fixes, the text field gets its text cuttoff when adding emojies. Anyone tried anything similar and knows a fix? (without downgrading to 1.1.x) ?

We have a view (screen 1) with an Android WebView embedded in it. We have a use case where we need to navigate to another screen (screen 2), then come back to the screen 1 with the WebView in it. We’re running into an issue with screen 1 recomposing and instantiating a new WebView. Since WebView is a little expensive to init, we were looking for a way to avoid reloading the WebView. I know it’s expected that screen 1 will go out of composition when you navigate away from it, but wanted to see if there are options to avoid that in this case. More in 🧵

While writing a custom layout I just discovered that having some

alignment

value I can do

// alignment = Alignment.Center
val x = alignment.align(myWidth, parentWidth, LayoutDirection.Rtl)

It's a (seemingly) small thing but very nice to not having repeat those boring

width/2 - myWidth/2

etc!

Hi, I am trying to write fast, deterministic screenshot tests for compose components, I am using facebook screenshot testing library : is there a way to ComposeView to draw or generate bitmap without attaching to a window? Or any recommendation to write fast screenshot tests for jetpack compose components without starting an activity

Hi, I ran into a problem with setting a `Slider`'s state/position. I use `Slider`s to control the brightness of lights and the level of shutters. I store the

Slider

position in a variable like this:

var shutterLevel by remember { mutableStateOf(shutter.shutterLevel) }

And in the

onValueChangeFinished

event, I pass it to the API to control the device. This all works as expected, but... I also listen to events from the server. So whenever the brightness is changed through another app or the shutter level is modified with the wall switch, the

Slider

position does not change because it was `remember`ed. I would be really happy if anyone could help me understand what I am missing here.

x-posting from #compiler

Hi, I am looking for way to add screen trace log for firebase performance metric to compose screens (similar to slow rendering/frozen frames metric of activity and fragment). Any idea where we should start and stop the trace?

Hi all android studio compose preview fails when using

androidx.activity:activity-compose

1.6.x

but works with version

1.4.x

Probably a very basic question. More in 🧵

Is there some way for compose to mix multiple types of lists? For example, the header and footer of the list are a lazycolumn, and the middle is a lazyverticalgrid. For example, If I use Paging3 with LazyVerticalGrid and I want to add a loading indicator at the bottom of the list, the indicator can only use a Grid instead of a whole row

I'm trying to add a "reset the saved bottom nav stack" on demand. Something like:

fun NavController.navToBottomNavItem(route: String, startFromStackRoot: Boolean = false) = navigate(route) {
    //how to use [startFromStackRoot]?
    popUpTo(DashboardScreenDestination.route) {
        saveState = true
    }
    launchSingleTop = true
    restoreState = true
}

The scenario in our app is, there's a botom menu and there's a Dashboard stack (app starts on that) and a Shop stack. The code above makes sure that when user navigates between different bottom bar items, he isn't starting from the root of the stack, but ends up where he left. So far so good. But there's one scenario, where I want to go from Dashboard directly to the root of the Shop stack, without restoring it's state. E.g. using the

startFromStackRoot

param.

Hi ! My app display a table with multiple text (see screenshot). I use LazyGridVertical. Each cell contains a text which will grow and will get bigger than the cell. Can I do what I want with my current implementation or should I use something else ? (in the exemple, if the

meu

grow up, it will be limited by the blue cell and I want it will be able to grow outside its cell)

Just released my 100% Jetpack Compose app on the play store 😛arty-parrot: thank you to the compose team for the hard work. It was truly a joy to work with ❤️ . https://twitter.com/RobertBMenke/status/1512496009808597003?s=20&t=cOH12iaSaia1isGvpBHDmQ

#rant So, am I the only one having this terrible AS performance? (not sure it's due to compose, but I don't remember facing stuff like this when I wasn't using compose)... 4 seconds to paste a short text? And no, I'm not running AS on a potato CPU usage rises to 25% for a paste

Is there a way to effectively exclude an element from contributing to content wrapping metrics? See this WIP layout where each 'Build' has two rows. I want to horizontally wrap to the top row i.e. the "8663, date, 3" and to disregard/truncate the Git hash below it as far as necessary.

I am using Hilt and navigation so when inject viewmodel without parameters it works but when viewModel has other classes injected i has crash

Caused by: java.lang.InstantiationException: java.lang.Class<com.xxx.screen.section.SViewModel> has no zero argument constructor

In my custom TopAppBar i send as parameter the action…

actions: @Composable RowScope.() -> Unit = {},

i’d like to have different action… how can create composable function like this

actions  = {
        IconButton(onClick = {  }) {
            Icon(imageVector = Icons.Default.Share, contentDescription = "", tint = BlueDentPad)
        }
        Icon(
            Icons.Filled.ColorLens,tint = BlueDentPad,
            contentDescription = "Localized description"
        )
    }

Would anyone have any insight into why this weird view transition behavior would be happening? If it’s not clear from the video… I don’t like that odd pop up and down behavior. Any ideas/advice would be greatly appreciated. here’s my transition code:

composable(LeafScreen.Account.route,
        enterTransition ={
            slideIntoContainer(AnimatedContentScope.SlideDirection.Right, tween(5_000))
        },
        exitTransition = {
            slideOutOfContainer(AnimatedContentScope.SlideDirection.Left, tween(5_000))
        }
        ) {....}
    composable(LeafScreen.SignIn.route,
        enterTransition ={
            slideIntoContainer(AnimatedContentScope.SlideDirection.Left, tween(5_000))
        },
        exitTransition = {
            slideOutOfContainer(AnimatedContentScope.SlideDirection.Right, tween(5_000))
        }
    ) {....}

I’m doing this navigation from a BottomSheetScaffold… I wonder if that has something to do with it? I’m using accompanist-navigation-animation:0.24.3-alpha i’m also using androidx.navigation:navigation-compose:2.4.2

Hello, I've just started with compose and I have a strange error.. "Composition requires an active composition context" while drawing my UI. This is the main activity:

setContent {
    MyTheme {
        Surface(color = MaterialTheme.colors.background) {
            Column(Modifier.fillMaxHeight()) {
                ListComposable(getList())
            }
        }
    }
}

The ListComposable:

@Composable
fun ListComposable(list: List<Info>, modifier: Modifier = Modifier) {
    LazyColumn(modifier) {
        items(items = groupedList, itemContent = { item ->
            Text(item.value) // CRASH HERE
        })
    }
}

I don't understand what's happening.. If I pass an empty list, it works. When it's non empty it crashes. The Info is a simple data class with just a value

I ams using ExoPlayer but player don’t play but i can see video if move timeline.

val sampleVideo = "<http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/BigBuckBunny.mp4>"

val context = LocalContext.current
val player = SimpleExoPlayer.Builder(context).build()
val playerView = PlayerView(context)
val mediaItem = MediaItem.fromUri(sampleVideo)
val playWhenReady by rememberSaveable {
    mutableStateOf(true)
}
player.setMediaItem(mediaItem)
playerView.player = player
LaunchedEffect(player) {
    player.prepare()
    player.playWhenReady = playWhenReady

}
AndroidView(factory = {
    playerView
})

Hey! Do we have possibility to check raw code generated by @Composable? I tried check Kotlin class byteCode but unfortunatelly I don't see there Composable additions.

https://developer.android.com/reference/kotlin/androidx/compose/runtime/Immutable

the doc of

@Immutable

said that “data classes that only contain val properties that do not have custom getters can safely be marked as Immutable if the types of properties are either primitive types or also Immutable” I thought the data class with val properties should have been treated as Stable (or Immutable) by Compiler , isn’t it ? if I don’t annotate

Person

with `@Immutable`，means the

PersonView

can’t skip the unnecessary Recomposition?