Version 1.2.0-alpha08 is out! • Update to Kotlin 1.6.20! • New experimental

LazyLayout

API is introduced. This allows you to build your own components like

LazyColumn

of

LazyVerticalGrid

. Note that the API is in its early stages and can be changed in the future releases • Bunch of updates to Paragraph, pointer input, Fonts Material 3 updates •

material3-window-size-class

is a new library that provides support for window size classes: a set of opinionated viewport breakpoints for you to design, develop, and test resizable application layouts against. • Lots of little updates

For the record the new material3 a10 require the 1.2 alpha08 compiler

Immediately encountering

Inconsistency between the count of nodes tracked by the state (0) and the children count on the SubcomposeLayout (1). Are you trying to use the state of the disposed SubcomposeLayout?

in all of my lazy lists after scrolling after upgrading to alpha 08

^^ mostly same posted before to ask for possible cause to build a repro but no answers. For me it seems to only be the lazy lists that have multiple item {} calls, the one with only 1 items{} does not seems to trigger that.

Is there any way to get more details about what android studio is doing when generating previews? They are VERY slow, and i’m trying to figure out if there’s anything i can do to speed the process up in my codebase

For the LazyLayout crash, do you have a sample that reproduces it or is it just happening in your app?

Hey this should create a Column where each item is a row with 4 thumbnails:

val files = remember { File(parent).listFiles()!!.toList().chunked(4) }
    LazyColumn {
        items(files.size) {
            Row {
                files[it].forEach { video ->
                    Thumbnail(video, size)
                }
            }
        }
    }

The problem is that the thumbnail thing takes a bit to load however the lazy column either calls the thumbnail method all at once or I'm doing something wrong because it's not loading. If I only take 4 of files it loads a few seconds and its fine

Hi all, am i the only one who is having issue with the preview when using

androidx.activity:activity-compose:	1.6.0-alpha01

?

hi guys, I am wondering if there is any library or approch that makes implementing compose navigation back stack for multiple screens inside activity easy

Hi folks :android-wave: Question about smart recompostion. If I have a composable function like:

@Composable
fun CustomView(myObject: MyObject) { //some Compose UI }

If

MyObject

isn't marked

@Stable

will this method be recomposed regardless if the values of

MyObject

have not change?

Hey! Does anyone have/know a public github repo that uses Jetpack Compose + Coroutines Flow AND contains Android Tests? I’m just starting with compose and I’m looking for inspirations 🙂

Hey all, I’m trying to do a bounce animation to an image. This image is placed inside a box. The box is the Composable that handles the click and should start the animation on the image inside it. I created the

bounce

function, an extension of Modifier. The

bounce

function receives a

shouldBounce

boolean that indicates if I should start the animation. I wonder if there is a better way to do that and move the

shouldBounce

boolean into the Modifier. With my current implementation, I need to define a

shouldBounce

boolean in every place that wants to use my bounce function. Maybe there is a way to catch the click event on both Box and Modifier? I attached some code examples in the first reply

How can I animate a Box to increase its size and revert the animation to its original size right after? I did try to use

animateFloatAsState

with 2 iterations but when the animation ends, the size of the box jumps to the

targetValue

If I have a

Row

and if a sum width of all of its children is less than

screenWidth

I want to use

.weight(1)

for them. Otherwise I want to use

.horizontalScroll()

on the

Row

. Is there a nice way to achieve this? I thought about

SubcomposeLayout

instead of

Row

but I'm not sure, because I need to also manipulate

Modifier

in this case (for scrolling)

Is there any way to achieve this kind of ui?

LazyColumn() {

Card() { 
      item{
          //Some ui

}

items(myItems) { item ->
         // item here
      }
  }
}

One of the problem that I am facing is with

DropDownMenu

, that it uses Column, thus cannot have huge number of items, without allowing it to populate all items at once, and this will lead to frame drop and crashes.

DropDownMenu

as of today cannot leverage

LazyColumn

as intrinsic size for

Subcomposelayouts

is not yet supported, and fixed height width cannot be given to the

LazyList

in

DropDownMenu

because of the use case. The use case is to show list of countries and choose one of them, and for that I am using the

DropDownMenu

but as the size of countries list is enough to make it draw after a few frame drop. I found an issues similar to this, ISSUETRACKER and is closed as it works as intended, because this is not meant for long lists, i guess. maybe a time for

LazyDropDownMenu

I tried replacing the

Column

with

LazyColumn

but that would not work because of the intrinsic measurements , and it works perfectly fine, when the

height

and

width

is supplied via modifier to

LazyColumn

.

Hi Folks, Need some guidance on 1. Whats the right patterns to pass parameters to Composable functions, if they are related and can be grouped. Compose API guidelines address this with

Jetpack Compose framework and Library development SHOULD declare hoisted state types as interfaces instead of abstract or open classes if they are not declared as final classes

at https://github.com/androidx/androidx/blob/androidx-main/compose/docs/compose-api-guidelines.md#default-policies-through-hoisted-state-objects It is understood that keeping Extensibility of hoisted type in mind, it’s better to expose Interface instead of concrete types, but if for a given environment if Extensibility is not a priority can we use

data

class a parameter to composables? is this encouraged?

data class BarState {
    val name: String
    val avatarUrl: String
}

@Composable
fun Bar(barState: BarState) {

If its okay to use as above, Again its understood that we can’t have access to LocalContext or Theme objects inside data class, an easy workaround is

data class BarState(
    val name: String
    val avatarUrl: String
    val contentColor: @Composable () -> Color = {
        MaterialTheme.colors.primary
    }
)

This makes the

BarState

data class mutable, hence the input to composable too, is this pattern still has any value? Have observed in the forum to avoid ever using

[Mutable]State<T>

in a parameter list to composable

getFoo: () -> Foo

is always going to be a more flexible parameter than

foo: State<Foo>

2. With this , if i can pas a function as a parameter to composable, why can’t i use same inside a data class? Any feedback/ inputs will be greatly helpful.

Any easy way to draw text in Compose? I wish I could draw text as I do drawCircle(), drawRect(), etc. in DrawScope.

Can someone tell me what is wrong here:

java.lang.IllegalStateException: Vertically scrollable component was measured with an infinity maximum height constraints, which is disallowed.

...

val scrollState = rememberScrollState()

Column(
	modifier = Modifier
		.fillMaxHeight()
		.verticalScroll(scrollState)
) {
    Card(modifier = Modifier.fillMaxWidth())
    Card(modifier = Modifier.fillMaxWidth()) {
        LazyVerticalGrid() {}
    }
}

The parent is the content slot of

BottomSheetScaffold

. I know it has to do with the

LazyVerticalGrid

, but both Cards measure the height by its content so I don't understand what the problem is. EDIT:

Card(modifier = Modifier.fillMaxWidth().weight(1f, false))
    Card(modifier = Modifier.fillMaxWidth().weight(1f, false)) {
        LazyVerticalGrid() {}
    }

Applying

weight

on both Cards solves the exception but now the

LazyVerticalGrid

is scrollable. I would like to wrap content height of the latter

Card

, is this possible?

What's the deal with the keyboard in compose 1.2? It used to be that navigating to a new screen with no textfield would hide the keyboard. That no longer appears to happen. Did I miss something or do I now need to track whether the keyboard should be shown?

Hello everyone, update to version 1.2.0-alpha08 of compose, I have an error in a lazyColumn when scrolling down, this does not happen to me in version 1.2.0-alpha07

java.lang.IllegalArgumentException: Inconsistency between the count of nodes tracked by the state (0) and the children count on the SubcomposeLayout (5). Are you trying to use the state of the disposed SubcomposeLayout?
                                                                                              	at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.makeSureStateIsConsistent(SubcomposeLayout.kt:514)
                                                                                              	at androidx.compose.ui.layout.LayoutNodeSubcompositionsState.subcompose(SubcomposeLayout.kt:391)

That's why i was asking how to get lazycolumn or lazyrow progression percentage. My animation isn't very smooth

Hey all :android-wave: , has anyone had luck getting a

HorizontalPager

to work inside of a

LazyColumn

? I've got a rather involved screen that has multiple

HorizontalPagers

for images and for tabs. All of the content should be vertically scrollable. Screenshot in thread.

Hello, how one can define a multiple derivedStatedOf? I have a code like below but they are called constantly when I log and recomposition happening. As far as I understand correctly, recomposition should only happen when

isPageTitleReached

and

isContentScrolled

changed, right?

val isPageTitleReached by derivedStateOf {
    remember {
        lazyListState.firstVisibleItemScrollOffset > 500
    }
}
val isContentScrolled by derivedStateOf {
    remember {
        lazyListState.firstVisibleItemScrollOffset > 600
    }
}

Does anyone know if the accompanist navigation libraries support combining the animated and bottom sheet navigators? Looking at the code would suggest so:

@ExperimentalAnimationApi
@Composable
fun rememberAnimatedNavController(
    vararg navigators: Navigator<out NavDestination>
): NavHostController {
    val animatedNavigator = remember { AnimatedComposeNavigator() }
    return rememberNavController(animatedNavigator, *navigators)
}

I assume i would pass the resolve of a rememberBottomSheetNavigator() call?

I get into a morass whenever I implement a TextField where the input is parsed to some other value type (e.g. LocalDate). Like, do I hoist the parsed value and hide the text input as internal to the composable adding the TextField?

Does

TabRow

has swipe behavior for its content? I'm wondering because its documentation says yes but it doesn't has it actually.

To navigate between fixed tabs, tap an individual tab, or swipe left or right in the content area.

How to achieve @ mentions like twitter and facebook similar to https://github.com/linkedin/Spyglass using compose. Any suggestions or ideas?

Hello everyone, i am showing multiple bottomSheet using BottomSheetScaffold but for closing the sheet i am creating a property like this, Is it fine to define properties like

closeSheet

and

openSheet

inside Composable because Main can recompose very often?

@Composable
fun Main() {

val closeSheet: () -> Unit = {
    scope.launch {
        scaffoldState.bottomSheetState.collapse()
    }
}

val openSheet: (BottomSheetScreen) -> Unit = {
    currentBottomSheet = it
    scope.launch {
        delay(100)
        scaffoldState.bottomSheetState.expand()
    }
}

if (scaffoldState.bottomSheetState.isCollapsed)
    currentBottomSheet = null

}