can AppBar has an option to center title, like in flutter. Some users prefer title in the center

AppBar(centerTitle: true, title: Text("Title"))

What’s the right way of conditionally adding Modifiers? I tried

Modifier.padding()
.preferredSize()
.apply {
    if(<some condition>) {
        this.then(Modifier.clickable { })
    }
}

but didn’t work

Hi. I'm getting:

* What went wrong:
lateinit property variantName has not been initialized

When trying to build my project form command line Config:

com.android.tools.build:gradle:7.0.0-alpha06

6.8.2-all.zip

compose

alpha12

Is there a replacement for

Spinner

yet?

PaddingValues is since alph12 just an interface what makes it very difficult to add or substract values. E.g. i want to add a FAB padding to the content padding of my LazyColumn. How can i do it now?

Perhaps a Studio question more-so than compose, but ... has anyone else had trouble getting the debugger to attach since updating everything to latest stuff for alpha 12?

I just tried to add a onbackpress dispatcher to a composable function. It works, but should I place it the function, SideEffect, LaunchedEffect, or DisposableEffect? I have to add it since it needs the call popBackStack() multiple times (or popUpTo)

I shere a way to get hold of a Surface in compose?

Hi all, I have made a custom composable for a Searchbar that takes as input a

query

and an

onValueChange: (String?) -> Unit

. The idea is that when I have the

onValueChange

with the string as null the UI is different and the TextField is empty, but I get an error when I call my onValueChange inside the clickable of the close icon. The error I get:

java.lang.AssertionError: org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl@63ae5d17: No such type argument slot: 1

@cb  I have a question about the ViewModels in the JetCaster app. https://github.com/android/compose-samples/blob/master/Jetcaster/app/src/main/java/com/example/jetcaster/ui/home/HomeViewModel.kt#L46 The state/_state variable (MutableStateFlow) is set by a collect on a combine in a launch on the viewModelScope.

val state: StateFlow<HomeViewState>
    get() = _state

  init {
    viewModelScope.launch {
      combine(
        ...
      }.collect {
        _state.value = it
      }
    }
  }

Why don't use return value of the combine method directly to the state variable?

val state = combine(
    ...
  )

Can someone explain the benefits of viewModelScope.launch -> collect in the init?

Hello, everyone! 😊 I have a complex Composable function that I decided to create two ViewModels in order to better split the responsibilities and both of them emits state (

sealed classes

via

StateFlow

). How could I handle the state changes? 1. Combine both states (with

.combine

) and create a third “ViewState” mixing and matching the two states. 2. Observe both individually and let my function recompose when they change 3. Another better approach? The first ViewModel has three states: EmptyList, LoadedList, Error and the second one has two: DataLoaded and Error. Thanks and advance! 🎉

Hi. Weird question Is it possible, from a module (library), having

MaterialTheme

, to obtain the

light

or

dark

version of a MaterialTheme?

Is it possible to create deep link pending intents with

navigation-compose

? Previously I was using

NavDeepLinkBuilder

but I can’t seem to get it work with compose.

FYI: https://twitter.com/AndroidDev/status/1362469578635362305

Are there docs anywhere for how to tell Android Gradle Plugin pre-4.2 what the correct Compose compiler dependency is? I am trying to build some compose code in a project that can’t use 4.2 yet, and it looks like agp 4.1 is trying to use obsolete compiler dependency coordinates.

Hi there, I'm migrating from compose 11 to 12 and It is recommended to use

Animatable

instead of

AnimatedFloatModel

, I was using

fling

and as

Animatable

has no fling method I've switched to using

animteDecay

, what I need is some way to use both

decay

and

adjustTarget

as I did with

AnimatedFloatModel

how can I achieve it now?

Any easy way to use a TopAppBar with centered title?

1576883: Concurrent recomposition API | https://android-review.googlesource.com/c/platform/frameworks/support/+/1576883 Status:

Merged

. Does this tell us we will have multithreaded composition soon? ☺️

I've got a strange issue, I've deployed a preview to the emulator, and now it wont show anything else! It'll only run the preview, I've tried cleaning and building, I've tried uninstalling the app from the emulator, but it just keeps showing the preview

I want to ask about an issue of DialogFragment. I create a DialogFragment using ComposeView which is normally work in alpha10:

class TestDialogFragment : DialogFragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ) = ComposeView(requireContext()).apply {
        setContent {
            Surface {
                TestDialogLayout()
            }
        }
    }
}

It's all normal with the deploy Preview

@Preview
@Compose
fun PreviewTestDialog() {
    TestDialogLayout()
}

But when I navigate from other fragment like:

TestDialogFragment().show(childFragmentManager, "Test")

or navigation way:

findNavController().navigate(MainFragmentDirections.actionToTestDialog())

Both calls gave me this crash log:

java.lang.IllegalStateException: ViewTreeLifecycleOwner not found from DecorView@bec849f[MainActivity]
        at androidx.compose.ui.platform.WindowRecomposerKt.createLifecycleAwareViewTreeRecomposer(WindowRecomposer.kt:231)
        at androidx.compose.ui.platform.WindowRecomposerKt.access$createLifecycleAwareViewTreeRecomposer(WindowRecomposer.kt:1)
        at androidx.compose.ui.platform.WindowRecomposerFactory$Companion$LifecycleAware$1.createRecomposer(WindowRecomposer.kt:115)
        at androidx.compose.ui.platform.WindowRecomposerPolicy.createAndInstallWindowRecomposer$ui_release(WindowRecomposer.kt:168)
        at androidx.compose.ui.platform.WindowRecomposerKt.getWindowRecomposer(WindowRecomposer.kt:216)
        at androidx.compose.ui.platform.AbstractComposeView.ensureCompositionCreated(ComposeView.kt:184)
        at androidx.compose.ui.platform.AbstractComposeView.onAttachedToWindow(ComposeView.kt:215)
        at android.view.View.dispatchAttachedToWindow(View.java:19553)

I'm not sure what happened during the alpha10 to alpha12... anyone has idea?

How do I make a canvas to write text on, draw images like stickers, etc.? I'm trying to make something like a photo editor. Should I use

ImageBitmap

? If yes, how do I draw text on the bitmap since there's no

drawText

for

Canvas(bitmap)

I have simple app with list but it has huge performance issues, Where should I start looking for potential issue with AS profiler?

I would like to store a Parcelable type via

rememberSaveable

but it doesn't get restored, instead it jumps always into the init method of

rememberSaveable

. What am I doing wrong?

val navigator: Navigator<T> by rememberSaveable(
        stateSaver = Navigator.saver(backDispatcher = backDispatcher),
        key = "State
    ) {
        println("initial")

        mutableStateOf(
            Navigator(
                initialConfiguration = initialConfiguration,
                backDispatcher = backDispatcher
            )
        )
    }

        fun <T : Parcelable> saver(
            backDispatcher: OnBackPressedDispatcher
        ) = listSaver<Navigator<T>, T>(
                save = { navigator -> navigator.backStack.toList() },
                restore = { backStack -> Navigator(backStack, backDispatcher) }
            )

I noticed that

rememberSaveable

is called internally multiple times, first time with my provided key and the other times it jumps into the else branch and generates a hash. Is this a bug? rememberSaveable:

val finalKey = if (!key.isNullOrEmpty()) {
        key
    } else {
        currentCompositeKeyHash().toString()
    }

Hello, is it possible to tint an icon to only a certain percent of its size? Something like half filled from left to right. I am trying to do a rating bar with stars, and would like to have the last star only filled at the certain percent (depending on the rate)

I’m looking for a complete example of

SubComposeLayout

. The compose sample has given sort of Scaffold of it and I’m not able not understand its usage from it. The layout I’m trying to build is as follows: my approach was to use

Text

as “mainContent” and pass its dimensions to a

Canvas

“dependentContent” to draw those accompanying lines. Any other suggestions/approaches are welcome

Hi. Can we expect Jetpack Compose beta launch on Feb 24?

Hi. Is there a Material Motion API for Navigation with Compose (or Compose in general)? Motion docs here: https://material.io/develop/android/theming/motion

Compose Beta is expected to release soon. People that already are using Compose, how is the performance compared to the Android View system?

I sometimes hear Compose UI. For example here and there. And Compose UI sounds temptingly nice. Is Compose UI another or a new name for Jetpack Compose?