I've implemented a date and time picker dialog in compsoe (https://github.com/vanpra/ComposeDateTimePicker) but for some reason it seems to skip a few frames when I show the dialog. I think this might be due to my hacky implementation of ViewPager for the date picker, so is there any way that I could improve it and make it more efficient? Currently I just Have a HorizontalScroller with 3 pages, one in the centre and one left and right of it and then when the user swipes right I animate it as they drag and when it reaches the boundary I snap it back to the centre. I find that when I'm rendering a simple layout on the pages it works fine but when I use it for the date picker it's a bit laggy.

Hi, Is it possible to have state

val isScanning: Boolean by viewModel.isScanning.collectAsState() // viewModel.isScanning is of type StateFlow<Boolean>

without an initial value? I have multiple locations where this behaviour makes me trouble. Or to be more concrete: When I write something like this below my state:

if (isScanning) viewModel.stopScan() else viewModel.startScan()

it should not trigger

stopScan()

nor

startScan()

when composable function is called. Instead it should trigger on next value change.

Trying to work with ViewModel and Compose, I’m not sure which one would be the preferred approach. Anyone have opinions on this? I’m worried the first one is inefficient, unless Compose somehow only recomposes the updated value (such as username)

I'm facing this error while using Android studio 4.2 canary 3 and compose 0.1.0-dev14 with kotlin 1.4-M2 and getting this error while gradle building Class 'Kotlin.Unit' is compiled by a pre-release version of Kotlin and cannot be loaded by this version of the compiler. Any help is appreciated.

I don’t make questions here for a while, then sorry if this is a FAQ, but here it goes… Why margin is not a modifier like padding is? 🤔

In the JetNews sample application in `Navigation.kt:98`:

This is expected to be replaced by the navigation component, but for now handle navigation manually.

What is “the navigation component?”

It's now

LazyColumItems

New question/feedback 😛 This is a simple `FilledTextField`… 1. Don’t you think the default background color should be transparent? 2. Don’t you think the start padding (or inner space 😅 between the border and the hint) is too big? 3. I can’t type using the laptop keyboard, I have to press the keys on the virtual keyboard… is this the [current] expected behavior?

Am I missing something obvious or is there only one (official) tutorial and one code lab for Compose? I’m trying to learn how to use a toggle/switch and really not sure where to start. The main marketing page only links to SO, this Slack group, and a big tracker.

It there any api to render html in a Text? And I don’t need to worry whether the content is plain text or html. Below is a screen shot from my sample and snippet what I am using to generate the view

@Composable
fun RenderArticle(article: ArticleUIModel) {
    Divider(thickness = 8.dp, color = MaterialTheme.colors.surface)
    Surface(shape = shapes.medium, elevation = 8.dp, color = MaterialTheme.colors.surface, modifier = Modifier.fillMaxWidth()) {
        Column(modifier = Modifier.padding(8.dp)) {
            Text(
                text = article.title,
                style = MaterialTheme.typography.h6,
                color = MaterialTheme.colors.onSurface,
                modifier = Modifier.padding(bottom = 4.dp)
            )
            Divider(thickness = 2.dp, color = MaterialTheme.colors.surface)
            Text(
                text = article.description,
                style = MaterialTheme.typography.body1,
                color = MaterialTheme.colors.onSurface,
                modifier = Modifier.padding(top = 4.dp)
            )
        }
    }
    Divider(thickness = 8.dp, color = MaterialTheme.colors.surface)
}

Hi everyone. Does Compose already have something similar to

Hero Animation

from

Flutter

or

Shared Element Transition

from

Android SDK

?

How can I change my state without pass a callback deep down into my composable “hierarchy”. I mean… I have a state on my composable

A

and this composable calls

B

which calls

C

. Is there a way to change the state in

C

? When we had

@Model

we just need to update attribute and it worked…

Hello, can someone help me to figure out how to make

LazyRowItems

with

wrap content

inside

LazyColumnItems

work correctly. In this example I have a row with images where each image has width 100dp. When I’m not passing modifier value with height in

LazyRowItems

it shows only one row and Text is not rendering , also it’s possible to scroll the page, but when I’m passing modifier with

preferredHeight

all works correctly,

wrapContentHeight

not working also.

LazyColumnItems(items = List(size = 30, init = { it })) { column ->
    if (column % 2 == 0) {
        LazyRowItems(
            items = List(size = 30, init = { it })
            //modifier = Modifier.preferredHeight(100.dp)
        ) { row ->
            Image(
                asset = imageAsset,
                modifier = Modifier.wrapContentHeight(100.dp).aspectRatio(1f)
            )
        }
    } else {
        Text(text = "$column")
    }
}

New question 😛 : Is there a way to save the scroll position of a

LazyColumnItems

? I’m using a

TabRow

to display two tabs and each one display a list of content. When I swap between the tabs, the scroll position of the list is lost.

Is there a current implemented NavigationDrawer in compose?

Yes

Does anyone know if the MaterialTheme or Ripple effects can be disabled. They seem to be quite laggy on the current versions and I was wondering if they can simply be turned off to improve performance?

Hi, Is there any way to set different background colors for the surface composable from the one defined in the color palette in the material theme? All surface composable background takes the same color as declared in the theme, but what if I want to have a different background color for different surface composable.

Want to use savedInstanceState extension in a Compose fragment and realized it doesn’t work. Anyone who tried it and made it work?

Is there a maxHeight constraint? I could’ve swore there was one before, but now I can’t seem to find anything related to max height/width just min.

The

BaseComponent

in itself basically is a lifecycleOwner, observes the parent's lifecycleowner (so copies those and will call on_destroy when onDispose is called on itself) and creates the dependency graph (by extending the parent's dependency graph). Does anyone have any pointers here? 🙂

is there any way to replace one composable function with another one with some kind of transition(Fading or Sliding)?

does anyone have a good sample on how to build a dropdown list? I can see

Dropdown

composable, but how to put everything together inside it is not clean. How to track selected item and modify it on select

Hey 👋 I ran into an edge case with Compose, and I’m not sure where to start debugging this. I created a simple composable UI that works fine on emulator, my device, even in Android Studio preview. But I’d like use it in combination with Android 11's Quick Access Device Control feature. When the user long presses on any system control, my own Activity is launched (this is where I use Compose) as something like a bottom sheet dialog with the Activity inside. And this is where my Compose UI breaks, because I can’t interact with anything inside the Activity, nothing reacts to any user input. Things that I’ve tried: • using a regular XML layout in this Activity -> every View is tappable, responds to input • using Compose in this Activity, but launching it as a regular Activity -> also OK Any ideas what’s the issue? Is it Compose, or the Android 11 Beta? Or some weird combination of both?

Hey, how can I change the color of shadow produced by

drawShadow()

modifier? I’m trying to make neumorphism design components. It would be great to have more control on shadows similar to the

box-shadow

property in CSS.

So when using AndroidView in the latest release, is there a way to get the view to “update”? Say for instance I’m using a custom AndroidView from a library that has buttons, changing text, whatever, compose will never recompose those views. They just have the last state (or sometimes the initial state) when it was drawn last. A good example is ExoPlayer’s PlayerView (which has the built in PlayerController which is never updated with information about the currently playing video. (The surface view works great though).

How does compose handle components that are out of view (ie. off the left or right of a view). Does it just ignore them until they are on visible?

Does

@Compose

support side effects, like launching a dialog or a

Snackbar

that auto-dismisses itself after a short time?

Work for a company that has to whitelist all artifacts we use and create local copies in artifactory. For these items

composeOptions {
        kotlinCompilerVersion "1.3.70-dev-withExperimentalGoogleExtensions-20200424"
        kotlinCompilerExtensionVersion "0.1.0-dev13"
    }

Where is that resolved from? Is it packaged with Studio?