Is the suggested way of working with

LazyColumn/LazyRow

to use mutable state for the items, so that updating a property of a single item doesn't cause all the visible items to recompose?

Question: Is there a way to prevent recomposition for a list of

Strings

from

LiveData

? When the items are sorted it should not cause recomposition. But seems like

observeAsState

forces recomposition every time. Even though I’m using

key

val value by viewModel.data.observeAsState()

LazyColumn {
    value?.forEach {
        item(key = it) {
            Text( text = "$it!")
        }
    }
}

Hello guys, I have a question regarding

DisposableEffect

. While using this effect I observed that if I move to another activity, then the

onDispose

lambda in the

DisposableEffect

of the composable in previous activity I navigated from didn’t get called. Is this an expected behaviour? That since I didn’t use compose navigation instead activity navigation

onDispose

isn’t called. And on the same topic can you suggest some other alternative of disposing data when composable moves out of view in case of activity navigation, my usecase is I want to send a tracking event everytime user moves out of screen.

Hello, as today is there any way to implement the long click drag reorder in the list composables ?

Can anyone advise on the wisdom of using

BasicTextField

to simply show text, in addition to allowing it to be editable? That is, instead of doing this:

var isEditing by remember { mutableStateOf(false) }
var text by remember { mutableStateOf("some editable text") }

if (isEditing) {
  BasicTextField(...)
} else {
  Text(...)
}

You do this:

var isEditing by remember { mutableStateOf(false) }
var text by remember { mutableStateOf("some editable text") }

BasicTextField(
  ...
  value = text,
  enabled = isEditing,
  decorationBox = { innerTextField ->
    Surface(
      ...
      // A visual cue to show that the field is being edited
      border = if (isEditing) BorderStroke(...) else null
    ) {
      innerTextField()
    }
  }
)

I am using Coil for image loading but I am not sure why my Images are reloading when coming back to the previous screen.

Any

SubcomposeLayout

specialists here? Trying to get the height of an inner child, code in 🧵

When using a normal

RecyclerView

that holds

ViewHolders

that just hold a

ComposeView

inside it, I am not getting the expected recomposition behaviour I am expecting. More details in thread 🧵

message has been deleted

Hi, How can I have a Circle

Checkbox

? I have tried

Modifier.clip(CircleShape)

but it’s not working.

When I try to get primaryColor from outside an annotated composable fun I get an error say "@Composable invocations can only happen from the context of a @Composable function" How to get a specific color from outside an annotated composable fun?

I have a question about memory management for classes which are instantiated within compose functions. I have a KMM project, and for the desktop version, I create a few pure Kotlin classes within my top level composable. I use a remember delegate which contains a enum class denoting each screen of the application (four screens total). When I want to navigate to a new screen in the desktop version, I just switch change that remembered enum and the recomposition occurs. So the thing I'm wondering is how to make sure that the classes (basically a Presenter, ViewModel, and Container class for a given screen) are being GCed properly after recomposition occurs. It's worth noting that they are instantiated within a composable that gets recomposed. Is there a general rule about what happens to such classes? My guess is that they are held on to via the slotTable, but I don't know for sure. I asked this in the #compose-desktop channel but it was suggested to ask here.

Originally shared in #multiplatform.

Seeing this compiler

BackendException

on AS when building a multi module KMM project which uses Jetpack compose

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

and this as render problems when preview tries to load in between

java.lang.NoSuchMethodError: 'void androidx.compose.material.TextKt.Text...'

Found a few other people who had the same issue here, on the issuetracker and even on SOF but none of the solutions that worked for them, worked for me unfortunately. More details in the 🧵 .

I have a

Composable

that displays an image, and when you click on it, it prints out the x and y position of the click, and the RGB color of the image. I’m noticing if the image is updated though, I end up getting RGB colors from the first image I clicked, not the latest. What is the correct way to handle this, as clearly I’m doing it wrong. Code in thread.

How do I create a state that depends on another state?

How to use image loaders with Canvas and drawImage? It seems Canvas API requires ImageBitmap instead of Painter, so the image loader APIs like coil rememberImagePainter don't work.

I'm trying to implement a timer using a

LaunchedEffect

, but it seems that

LaunchedEffect

gets canceled on recompose.

@Composable
fun TimeDisplay(viewModel: TimeDisplayViewModel) {
  val properties: Map<String, Long> by viewModel.properties.collectAsState()
  var timeRemaining by rememeber { mutableStateOf(0) }
  
  Text(timeRemaining.toString)
  
  val timeProperty = properties["time"]
  LaunchedEffect(timeProperty) {
    val currentTime = System.currentTimeMillis()
    while (timeProperty > currentTime) {
      timeRemaining = timeProperty - currentTime
      delay(1000L)
    }
    timeRemaining = 0L
  }
}

The

LaunchedEffect

is always canceled during the delay.

properties

is updated with an unrelated value.

Hello 👋 is there a way to detect drag events and also detect when the user lifts their finger up? I've tried

changeToUp

from the Pointer input scope but that doesn't seem to do what I think.. currently I use

PointerInput

and

detectDragGestures

.

Hello everyone 👋🏾. while testing out compose on our project, we realised that our ui testing framework (Appium) uses view ids to run tests on the UI. is there a way to specify ids for composables. I also read about the compose semantics tree but I'm not sure how it can help. Thanks 🙏🏾

hi all. I’m still grasping thinking in Compose, and I’m wondering if someone can guide me on the “correct” way to do this in the world of Compose. I have a parent screen which holds some master context (let’s say

someParentId

), and that screen is made up of some child Composables, and those Composables each have their own ViewModels. I would like to re-initialize those child ViewModels when

someParentId

changes, so that they re-load their data (and in turn recompose whatever is required) if I completely blow away the child ViewModels when

someParentId

changes and construct new ones, the corresponding UI must be recomposed every time, right? and that would be a very inefficient way to do it? so does this mean that the correct way would be to have ParentViewModel hold a reference to ChildA ViewModel and ChildB ViewModel, and when

someParentId

changes I can just get my existing child ViewModel references, and tell them to fetch the relevant new data? (hastily drawn pic for reference in case the relationships were unclear)

Anyone noticed that APK size has increased drastically when using compose. Starter application in XML takes

4.2 MB

whereas starter app in Compose is

7.2 MB

having 5

.dex

files. Why there are so many dex files in a starter app? Edit: I noticed that starter app in XML also has 3 dex files, why is this happening, does this have anything to do with recent versions of Android gradle plugin?

Hi, how can i draw this shadow in compose? this shadow info in figma

Divider(
    color = MaterialTheme.colors.background,
    modifier = Modifier
        .height(150.dp)
        .width(2.dp)
)

How Can I add rounded corners for that divider?

Hi, I don't know if I did something wrong reporting the issue but I posted a bug on September 30 with a reproducible sample and it's still not even acknowledge today: https://issuetracker.google.com/issues/201556419 Should have I done something different when reporting it?

Hi guys, How can I open soft keyboard in full screen mode while in landscape orientation in Jetpack Compose while typing in a BasicTextField? This used to be the default behaviour in View world.

Anyone know a simple way to preload an

Image

? I'm using Accompanist's

HorizontalPager

. A page shows an

Image

from a URL. I'd like to load one page ahead so paging feels faster.

Hello. What is the best way to decorate each symbol in text field? Each symbol in the text field should be in own composable. It should look like first is a round square, second is a circle and so on

Hey I have a question about compose, if I have a complex screen with many states, like • Some permissions need to be granted to show any UI • UI loading • UI error • etc What is the best practise? Like defining a master state data class (with many constructor arguments) and pass it from top to bottom, where I pass the events from bottom to top? I read that passing viewModel it self as method argument in composable is not a good practise since this would imply states within the composable method

My view model has a computed property - it forwards to an underlying model that does not know about the

MutableState

type. Is there a way to signal Compose when this computed property has changed, without keeping a separate copy of the data in my view model as a

MutableState

? (In SwiftUI I do this with

objectWillChange.send()

)