Hey people, have a question about sealed interfaces and stability/skippability 🧵

Hi everyone, I currently have a list of objects stored in my ViewModel state which has paths of videos for e.g. [{"filename1.mp4", [00:05:00, 01:15:00]}, {"filename2.mp4", [00🔟00, 00:25:00]}]. How can I play one video after another using Compose?

Hi i am struggling to understand the lifecycle of my viewmodels within my current android jetpack compose application

Snapshot.withMutableSnapshot {
 itemList.forEach { item -> _messagesStateMap[someIndex] = item }
}

Would this be a proper usecase for Snapshot? I dont want to trigger UI Update on every iteration of the loop So, with this, I guess it’ll only trigger update after the

apply

is called. What do you guys think?

How do I make a composable opaque? The composable doesn;t consume click events but the underlying composable can consume the events when they are in a box. For example in a flutter app, we can use IgnorePointer on a widget to make it opaque. Looking for something similar in jetpack compose.

I'm seeing an issue where

AnimatedVisibility

runs an

EnterTransition

of

slideInHorizontally

twice in some scenarios. Anyone else seeing anything like this - https://issuetracker.google.com/issues/260870116

Hi everyone, how can I refresh/call method on my previous screen after I pop/navigate up on my second screen? I did something similar before, but in Flutter:

Navigator.of(context).push(...).then(*do something after pop()*)

How can I do this in Compose navigation?

Hello! Is it possible to use the old navigation component and as a destination declare a fragment that uses the compose navigation component? I was thinking about implementing the new features like that in order to start implementing compose nav graphs before being fully migrated but it seems that it does not work...

private val locationFilter =
    BrowseEventsFilter.LocationFilter(location = MutableStateFlow(null))

private val categoryFilter =
    BrowseEventsFilter.CategoryFilter(category = MutableStateFlow(null))

private val periodFilter = BrowseEventsFilter.PeriodFilter(
    period = MutableStateFlow(Period.Any),
    dateRange = MutableStateFlow(null)
)

val filtersState = MutableStateFlow(
    listOf(
        periodFilter,
        locationFilter,
        categoryFilter
    )
)

viewModelScope.launch(<http://dispatchers.io|dispatchers.io>) {

            filtersState.collect {

and in the activity

val filtersState by browseEventsViewModel.filtersState.collectAsState()

is this not enough to guarantee a recomposition if something inside filterState changes?

I have a Scaffold TopBar element, and containerColor is primary color. When I set my action to be TextButton, that button has same primary color as TopBar container. How do I approach this so my TextButton has actually different traits (text and ripple effect to be onPrimary color)?

Hello, is it possible to use compose paging on a stacked card (like tinder)? So when the user swipe the card, it should behave like when user scroll on LazyPaging items. Its already working fine on LazyColumn with paging items, but when I use Box and forEach to stack the card, the paging did not trigger the load next page function

I remember in the earlier days of Compose seeing a bunch of sample apps with a

Scaffold

at (or near) the top of their hierarchy, meaning each individual “screen” was wrapped by one “grandparent” Scaffold, which meant you would have a single source of controlling a drawer layout and a snackbar host. These days I don’t see that pattern as much, and the pattern is more like one Scaffold for each screen. Which of these is the recommended way of doing things? My guess is the second one (many Scaffolds) is the way but I wanted to hear thoughts from others 🙏

Is there a viable way to make an item in LazyColumn fill the available space when the list does not fill all of the screen? With the following Arrangement implementation I was able to make a LazyColumn place the last item either at the middle of the available space or at the end (if the list is larger than the screen):

@Stable
object TopLastAtMiddleArrangement : Arrangement.Vertical {

    override fun Density.arrange(
        totalSize: Int,
        sizes: IntArray,
        outPositions: IntArray
    ) {
        var currentOffset = 0
        sizes.forEachIndexed { index, size ->
            if (index == sizes.lastIndex) {
                val remaining = totalSize - currentOffset - size
                outPositions[index] = if (remaining > 0) (remaining / 2) + currentOffset else currentOffset
            } else {
                outPositions[index] = currentOffset
                currentOffset += size
            }
        }
    }
}

I was hoping to make an implementation able to, when there is space, expand the given item to fill the gap. I was hoping to be able to do that by changing the sizes array, but that didn't seem to work. Any ideas/suggestions?

how to show the keyboard immediately when a screen is opened with Jetpack Compose and kotlin?

Hi everyone! Is there a way or a resource I could refer to in order to achieve a side effect on a lazyrow when an item is scrolled? • The side effect should be only executed only if the current

firstVisibleItemIndex

after scroll is different than before • The side effect should not be executed the item is not fully scrolled I am implementing a fullscreen lazyrow items with a snap behavior Thanks!

Hi i can delete TextField padding, i am using a OutlinedTextField

What is the best way to measure the performance of a composable and get the data from the user base using Firebase traces (and not just tracing on our own device(s)) ? The main question here is about where to start the trace and where to stop it.

I have this composable function, and how can I preview this??

@Composable
fun NutritionalBalanceRoute(
    viewModel: NutritionalBalanceViewModel = hiltViewModel()
) {
    Column(
        modifier = Modifier.fillMaxSize(),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {
        Text(
            text = "Nutrition",
            style = MaterialTheme.typography.headlineMedium
        )
    }
}

I tried with

@Preview
@Composable
fun PreviewNutritionalBalanceRoute(){
    val viewModel = hiltViewModel<NutritionalBalanceViewModel>()
    Surface {
        NutritionalBalanceRoute(viewModel)
    }
}

but it didn't work.

Is there an easy way to add custom

TextDecoration

to compose text? I’d like to have a dashed underline. It seems like I have to go down deep into the text painter and customize it….

Consider following

Composable

.

Box(
    modifier = Modifier
        .size(100.dp)
        .background(Color.Blue)
        .clickable {
            // parent click listener
            Timber.d("parent click")
        }
) {
    Box(
        modifier = Modifier
            .size(50.dp)
            .background(Color.Red)
    ) {
        // children
    }

    // ...
}

When clicking on the red

Box

the parent

Composable

consumes the click event even though the red box is in front of it. This looks like a weird default behavior to be. Different from the

View

system.... However when the red

Box

has a click listener of its own the behavior is correct and the red

Box

click listener is triggered. Is there a better way to let the red

Box

consume the event without putting an explicit

clickable

modifier on it?

Can 2 views share the same viewmodel without loosing the state, so both can mutate it?

Accessibility related question I am working on a mobility app in which we have a

Column

listing nearby Stops. These Stop items show which Lines stop there. When Talkback reaches the Lines, I want it to add a prefix before starting to read out the line numbers which says “Departs from here: ” and then the line numbers, so in the screenshot it would read the name of the stop, then the distance from the stop and then: “Departs form here: bus 231, night bus 973, night bus 996, night bus 996A” Currently I am adding a 1x1 Spacer before the Green box (which is a Column in my code) with the

contentDescription

set to “Departs from here: ” but it feels like a nasty hack. Is there a better way to add a prefix to a group of elements?

Hello all, I just filed this bug (https://issuetracker.google.com/issues/261078350) regarding a crash that occurs when placing an

AbstractComposeView

inside of a

BottomSheetDialog

(from the material design library). Wondering if anyone else has run into this before & found a solution. Error starts with:

java.lang.IllegalStateException: ViewTreeLifecycleOwner not found from android.widget.FrameLayout

I am looking at the Tivi repository (chrisbanes/tivi) and notice that they use a Mutex to update a MutableStateFlow. Isn't it the case that MutableStateflow.update is already threa-safe?

What is the difference between LaunchedEffect(Unit) and LaunchedEffect(true)?

Should I use multiple states per screen like this:

private var screenState by mutableStateOf(ScreenState())
private var dialogOneState by mutableStateOf(DialogOneState())
private var lazyColumnState by mutableStateOf(LazyColumnState())

or only one?

Is kover provides coverage in jetpack compose ?

Is it an expected behavior that Live Edit is invoked when some KDoc block is edited? It has no effect on the behavior and still imposes high resource consumption.