For anyone trying to use compose and hilt to inject viewModels along with compose nav host composable, here is a github issue to be aware of https://github.com/google/dagger/issues/2166#issuecomment-769162910. In short, if you have a navHost that defines routes then viewModel inject stops working in those routes. For e.g

NavHost(navController = navController, startDestination = "splash") {
            composable("splash") {
                SplashScreen(navController)
            }
            composable("home") {
                HomeScreen()
            }
        }

and you SplashScreen was defined somewhat like this

@Composable
fun SplashScreen(navController: NavHostController) {
    
    val viewModel: SplashViewModel = viewModel()

The injection will not work if your SplashScreenViewModel takes non zero constructor params. In order to fix this you need to inject the viewModel somewhat like this

val viewModel: SplashViewModel = viewModel(
        factory = HiltViewModelFactory(
            LocalContext.current,
            navController.getBackStackEntry("splash")
        )
    )

and this is possible by using the

androidx.hilt:hilt-navigation:1.0.0-alpha03

library. I spent the last hour trying to debug why despite everything being right, the injection wouldn’t work 😄

Does Jetpack Compose have a concept of providing

systemGestureExclusionRects

for gesture navigation? Alternatively, is it possible to obtain the screen bounds of a particular composable so I can use it to set these?

Just wanted to clarify whether my understanding of LaunchedEffect and rememberUpdatedState is correct. This is an example from Android developer site @Composable fun NotificationHost(state: NotificationState, onTimeout: (Notification) -> Unit) { val currentOnTimeout by rememberUpdatedState(onTimeout) state.currentNotification?.let { currentNotification -> LaunchedEffect(currentNotification) { // We should not restart this delay if onTimeout changes, but we want to call // the onTimeout we were last recomposed with when it completes. delay(NotificationTimeout) currentOnTimeout(currentNotification) } } // ... } -- LaunchedEffect will be executed during initial composition. -- And after that the effect will only run if the effect's parameters change. -- Sometimes the effect refers a value or event callback in its code block which is not passed as a parameter to the effect.( We don't want to restart the effect when the value or the event callback changes) . But we need to remember them during recomposition. Also they need to be updated with the new value or callback during recomposition. So we use rememberUpdatedState. This way if the effect is relaunched when one of its key is updated it will get the updated value or callback which is referred in the effect. -- LaunchedEffect will survive recompositions Thanks

How could I prevent scroll gestures from a

LazyColumn

inside a bottom sheet from dismissing the sheet? is it possible to disable the sheet swipe gestures within a certain boundary? (in my case I want to disable them over the

LazyColumn

)

BackHandler

seems to not intercept system back presses on

AppCompatActivity

restart in my case (in nested

NavHost

composables). Is it a known issue? 🤔

SharedElement transition in Jetpack Compose is possible? Can any one please share sample project. I've found one but its not updated from a long time https://github.com/mobnetic/compose-shared-element

I'm trying to make SaveableStateProvider work - I have Parcelable immutable data classes as keys (so hashCode/equals) and ensure SavedStateProviders exist while the keys are added, yet I'm still losing the saved state. What am I missing?

Compose AndroidView with GoogleMap has an issues on devices with android 6 & 7 (didn’t test android 5 tho). I used sample project Crane for reproduction. You can check below GIF and issueTracker. Anyone has a workaround until fix? https://issuetracker.google.com/issues/182063556

I think I am doing something really bad here. Is there a way to see which part of my code effects performance so bad?

I can't make a 1.dp height linear progress bar

LinearProgressIndicator(Modifier.fillMaxWidth().height(1.dp))

The implementation hard codes its size it seems:

Canvas(
    modifier
        .progressSemantics()
        .size(LinearIndicatorWidth, LinearIndicatorHeight)
        .focusable()

Any solution?

Is it possible to apply a tint to an

ImageBitmap

?

1.4.31 is not compatible.

Hi all! If I use jetpack compose in my android library, does an app that uses my library also have to use jetpack compose? (With the non-stable gradle plugin setup, etc.)? I'd like to use jetpack compose in my libraries, but some of my apps cannot use the non-stable gradle plugin setups required for jetpack compose in production.

I upgraded to

1.0.0-beta01

, and the

preferredSize

modifier gives an error. What is the new modifier for that?

Hi, I'm trying to update my state with reducer. The only way I was able to achieve that was by using

ViewModel

and

collectAsState

but by doing that I lost the ability to change state in the interactive mode in android studio. Is there something I'm missing?

I have one question. how can i handle rember state on bottomnavigation switch. I have a home screen with a composable that has a

var isPlayingState by remember { mutableStateOf(false) }

and set it in clickable (Box)

isPlayingState = if (player.isPlaying) {
    player.pause()
    false
} else {
    player.play()
    true
}

If i navigate to the second tab and navigate back the value ist false and not the last state i set ?why?

Can I build and run jetpack compose project with stable AS version?

Hello I'm trying to implement a bottom-sheet which will launch on the icon click on the top bar. But i'm getting a weird result below are the details

Although everyone is working on countdown challenge, I went back to my old video player project and updated it to beta01. Also, I added this youtube like MinimizableLayout. It's amazing how simple it is to implement something like this with compose.

Any ETA for the Compose beta02 release?👀

about

#AndroidDevChallenge

… My github actions fails on this test:

com.example.androiddevchallenge.ExampleInstrumentedTest > sampleTest[test(AVD) - 10] FAILED 
254
	kotlin.UninitializedPropertyAccessException: lateinit property remeasurement has not been initialized
255
	at androidx.compose.foundation.lazy.LazyListState.snapToItemIndexInternal$foundation_release(LazyListState.kt:186)

I haven’t touch that part. Any of you faced similar?

If I want to get the measurements for a given Composable - say a Text, how would I go about that? For reference, my use case is that I'm trying to basically animate a column up or down a certain number of items within the column. So my thought is I'd use one of the animation state primitives and change the translation y by some multiple of the height of an item inside the column

More questions! I'm struggling to get my brain to understand animations in declarative land. I've been looking at the animation codelab which is helpful, but I'm still struggling. Let's say I have some immutable composable and I want to animate changes to it whenever its recomposed with a new value. Is that possible? Is that something that you'd do at the immutable composable layer or at some wrapper layer?

This is probably something easy I'm missing, but is there an easy way to animate between ImageVector states? I couldn't find an appropriate animate*AsState nor a suitable TwoWayConverter to use with animateValueAsState. For context, the icon is chosen according to a Boolean value (which also lacks an animate*AsState function).

Is there a built in way to create an ImageBitmap from an array of rgba values?

why doesn't drawArc have the cap parameter? I need to round the line I draw.

Having some trouble understanding the

key

Composable. Noticed its usage in Jetcaster’s Pager:

for (page in minPage..maxPage) {
    val pageData = PageData(page)
    val scope = PagerScope(state, page)
    key(pageData) {
        Box(contentAlignment = Alignment.Center, modifier = pageData) {
            scope.pageContent()
        }
    }
}

What exactly is the purpose of

key

here? Would love some more insight into how/what it does in general. The implementation of

key

doesn’t betray its functionality, since the function params are “unused”.

Does anyone know how to get a BottomAppBar to hide upon scroll of a LazyColumn?