When using createEmptyComposeRule and launching the activity myself, is there a way to still perform actions and make assertions using the EmptyComposeRule? The activity needs to take in data using Intents, but is otherwise fully Compose. After I create an empty compose rule, then launch the activity using ActivityScenario.launch<MyActivity>(intent), I get an error when I try to make an assertion on the rule.

Please file an issue with a repro project here: https://issuetracker.google.com/issues/new?component=742043

can recomposition be described in terms of Views like:

"recomposition is the process of removing all of the views on the screen > going over your code again > depending on state > adding different views to the screen"

?

Hey, I heard Flows are very bad for the performance of Jetpack Compose due to the fact that they are not stable. My whole app is using flows, what else should I use? (MVVM)

Hey, folks! I’m creating heavy AndroidViews (ads) inside

LazyVerticalGrid

and noticed that factory param in

AndroidView

Composable is called each time an item loses and obtains visibility. It’s not ideal, as creating and destroying heavy Views makes scroll not smooth due to janky frames. Is there any mechanism in Compose that would allow me recycle Views inside LazyVerticalGrid apart from creating a pool of Views and managing it myself?

👋 Is there a way to disable automatic code and compose preview side-by-side IJ layout when opening a kt file with composables in it?

Similar 🧵: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1656496283156679

For compose

rememberSaveable

, are the variables restore sequence per the order of the line coded? I have a case where it seems that way (or perhaps a Google bug?). To explain clearly what I meant with full code in https://stackoverflow.com/questions/73947154/remembersaveable-restore-value-type-influenced-by-the-order-of-the-code Can someone help? 🙏

Hello guys, I am learning in State in jetpack compose. I found that State holders as source of truth. So created my some data can you guys guide me if I am doing wrong here.

how would I get an instance of navController to give to the Composable in Previews?

You could align by the last baseline, but that might not work when the text is empty. @Halil Ozercan do you have any ideas?

In most of these cases, creating a library for hosting just a few lines of code doesn’t make sense. Unfortunately, there is no good way for these code snippets to be discoverable once they are shared and they often get lost in the deep corners of Slack 😞

This article suggest that we should pass all parameters with lambdas (among the other things) to optimize performances with compose. Edit: what I'm asking is "when is OK (performance wise) for a Composable to not be skippable" From what I understood tho': 1) recomposition is not really an issue if it happens in an "empty" function that just pass parameters to other composables without actually drawing any UI 2) the in-between composables that do not use parameters directly but just pass them down to other composables will be skipped. Are my 2 assumption above false? Is the article right? Thanks https://t.co/9kC6BaTJbi

Compose Compiler with Kotlin 1.7.20 support is now published on gmaven.

Hi folks, I remember reading something about composition local providers very sparingly in your compose code in this channel but I can't find it again. Is anyone aware of any downsides of relying too much on composition locals ?

Is it possible for a composable that's always part of our UI tree to leave the composition and then re-enter, without the "on resume" lifecycle callback being called?

Hi folks. Had a question around compose navigation multiple back stacks. Working on a requirement where each of the 4 bottom navigation tabs has its own backstack. That can be easily achieved by using the multiple backstack feature in compose navigation. However a bug I’m noticing is that one of the tabs navigates to another, the bottom item associated with that tab isn’t selected anymore. This is because the current route of the navgraph isn’t any of the 4 tabs anymore and is something else. question: Does anyone have a good way of dealing with this? I know of a way which requires me going through the backqueue in navhostcontroller and figuring it out using that. It works mostly but seems hacky. Wanted to see if other folks have had to deal with that

Hi, I have the following code

@Composable
fun MyComposableFun(textValue: String) {

    val newTextValue = remember(textValue) { mutableStateOf(textvalue) }

    val myComposeView = remember {
        MyComposable().apply {
            setContent { Text(newTextValue) }
        }
    }

    Column(horizontalAlignment = Alignment.CenterHorizontally) {
        Text("Title: $newTextValue")
        myComposeView.myComposable?.invoke()
    }
}

class MyComposable {
    var myComposable: (@Composable () -> Unit)? = null

    fun setContent(content: @Composable () -> Unit) {
        myComposable = content
    }
}

On initial load it's okay. But when

textValue

changed, and the function got called again, • The

Text("Title: $newTextValue")

got updated - which is good • The

setContent { Text(newTextValue) }

don't get updated. Why? Did I get anything wrong?

I’ve had a lot of luck with Live Edit in Flamingo Canary 1. Are you on that one? But in general it is a feature which is not that reliable, at least not yet.

How do I use wide gamut colors in compose? In my app i had

values/colors.xml

and

values-widecg/colors.xml

that were picked up by my theme. There's a constructor for

Color()

that takes

colorSpace = ColorSpaces.ExtendedSrgb

, I assume i have to use this. Than what? Just check if the current window display is wide gamut to pic one color or the other? Anything else i need to do? Any handy Local provider to obtain this or do i need to go through the

LocalContext

, find the activity etc...? Do I need the activity

android:colorMode="wideColorGamut"

? Couldn't find much documentation around this topic. Thanks

Just pushed my first 100% compose App to the Play Store. The pre-launch report discovered 2x crashes. And I can’t figure out what the Problem is with compose. Can you help me?

Fatal Exception: java.lang.IndexOutOfBoundsException: offset(13) should be less than line limit(12)
       at android.text.TextLine.measure(TextLine.java:389)
       at android.text.Layout.getHorizontal(Layout.java:1246)
       at android.text.Layout.getHorizontal(Layout.java:1222)
       at android.text.Layout.getPrimaryHorizontal(Layout.java:1192)
       at android.text.Layout.getPrimaryHorizontal(Layout.java:1181)
       at androidx.compose.ui.text.android.LayoutHelper.getDownstreamHorizontal(LayoutHelper.java:11)
       at androidx.compose.ui.text.android.TextLayout.getPrimaryHorizontal(TextLayout.java:11)
       at androidx.compose.ui.text.platform.AndroidParagraph.b(AndroidParagraph.java:11)
       at androidx.compose.ui.text.MultiParagraph.getBoundingBox(MultiParagraph.java:42)
       at androidx.compose.ui.text.TextLayoutResult.getBoundingBox(TextLayoutResult.java:42)
       at androidx.compose.ui.platform.AndroidComposeViewAccessibilityDelegateCompat.addExtraDataToAccessibilityNodeInfoHelper(AndroidComposeViewAccessibilityDelegateCompat.java:164)
       at androidx.compose.ui.platform.AndroidComposeViewAccessibilityDelegateCompat$MyNodeProvider.addExtraDataToAccessibilityNodeInfo(AndroidComposeViewAccessibilityDelegateCompat.java:164)
       at android.view.AccessibilityInteractionController.populateAccessibilityNodeInfoForView(AccessibilityInteractionController.java:430)
       at android.view.AccessibilityInteractionController.findAccessibilityNodeInfoByAccessibilityIdUiThread(AccessibilityInteractionController.java:363)
       at android.view.AccessibilityInteractionController.-$$Nest$mfindAccessibilityNodeInfoByAccessibilityIdUiThread(AccessibilityInteractionController.java)
       at android.view.AccessibilityInteractionController$PrivateHandler.handleMessage(AccessibilityInteractionController.java:1647)
       at android.os.Handler.dispatchMessage(Handler.java:106)
       at android.os.Looper.loopOnce(Looper.java:201)
       at android.os.Looper.loop(Looper.java:288)
       at android.app.ActivityThread.main(ActivityThread.java:7898)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)

How is this data class inferred as unstable? Which contract it doesn't comply with?

data class User(val id: Int) {
    private var name = "a"
}

unstable class User {
  stable val id: Int
  stable var name: String
  <runtime stability> = Unstable
}

This is not going to be too specfiic, but maybe omeone can point me in the right direction at least. We get very weird random crashes (sometimes it's NPE, sometimes IndexOutOfBounds and sometimes low level stuff like SIGSEGV). It can be reproduced by rapidly clicking a refresh button which asynchronously (but quickly, think milliseconds) updates the composable state. Only on production (non-debuggable, proguarded) builds.

Is there a way in compose to implement

CollapsingToolbarLayout

? With the new material design 3 I can see that it is possible to use

LargeTopAppBar

and it has a

scrollBehaviour

but it is not working with images and also it is not high enough and it is always reopening if I scroll up not just when I reach the top of the screen.

I have a LazyColumn which show a MutableStateList of items: is it normal that when I update a single item in the list, all the visible items get recomposed? even though I they do not change in any way

You should pass the shape to the

.border()

modifier. Also I think

.clip()

is not needed in this case.

Hi, Which dependency you use for loading images in Compose?

Does anyone know a good way to change the current locale in a paparazzi test that uses compose? I have a parameterized test:

@RunWith(Parameterized::class)
class ScreenshotTest(val selectedLocale: Locale) {
    @get:Rule
    val paparazzi: Paparazzi = Paparazzi(
        theme = "android:Theme.MaterialComponents.Light.NoActionBar",
        deviceConfig = DeviceConfig.NEXUS_5.copy(softButtons = false, screenHeight = 3000),
        renderingMode = SessionParams.RenderingMode.V_SCROLL
    )

    companion object {
        @Parameterized.Parameters(name = "{0}")
        @JvmStatic
        fun locales() = listOf(
            Locale("en", "US"),
            Locale("es", "US"),
            Locale("fr", "CA"),
            Locale("it", "IT"),
        )
    }

}

But i’m having trouble getting the locale to change. I tried Locale.setDefault before calling paparazzi.snapshot, but that didn’t seem to have any effect. I’m still getting english strings.

Side effect is retaining old value from returned composable is this expected? and how to avoid this?

@Composable
fun foo(): Int {
    var counter by mutableStateOf(0)
    LaunchedEffect(Unit) {
        while (true) {
            delay(500)
            counter++
            println("Foo: $counter")
        }
    }
    return counter
}

@Composable
fun bar() {
    val foo = foo()
    LaunchedEffect(Unit) {
        while (true) {
            delay(500)
            println("Bar: $foo")
        }
    }
}

Output in thread, but the the second composable will always returns: "Bar: 0"