kotlinlang #compose

, the memory profiler, after setting focus on/selecting the text field without typing anything, shows that Java allocations are happening non-stop, it keeps goin up until it gets GCed, then start going up again over n over, am I missing something?

MyApplicationTheme {
    // A surface container using the 'background' color from the theme
    Surface(color = MaterialTheme.colors.background) {
        OutlinedTextField(value = "Ok", onValueChange = {})
    }
}

Bacho Kurtanidze

09/02/2021, 12:55 PM

constrainAs(title_textRef, { end.linkTo(parent.end, ~dimensionResource~(id = R.dimen.dp_16)) } How can I reference dimensionResource inside of non-composable code block?

Scott Kruse

09/02/2021, 2:28 PM

Random thought, it would be useful to have a XML -> Compose conversion tool in the IDE

Tolriq

09/02/2021, 4:43 PM

What would be the proper way to animate a bottomnavigationbar in a scaffold when expanding a bottomsheet? Applying an offset is not enough as it leaves the padding to the content and also changing the height via a modifier triggers too many recomposition and seems to break the swiping 😞

Chris Johnson

09/02/2021, 7:03 PM

:android-wave: Is there a way to measure a child before placing it and then fill the screen with the available amount of those children? Currently I'm creating a

Layout

for measurement of the child and then another

Layout

that will place X amount of those children based on screen height. The problem I ran into was each child I'm placing needs to be unique/not being currently laid out for the system to not give me

"Place was called on a node which was placed already"

Anthony

09/02/2021, 7:38 PM

Has anyone tried out

androidx.navigation:navigation-compose:2.4.0-alpha08

yet? I seem to be getting an error every time I navigate back to a composable using a navigation graph scope viewmodel.

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Lilly

09/02/2021, 9:49 PM

What is the right way to handle

Flow

that comes from view model? I have a

Flow

that produces values for

LazyColumn

. Do I have to put the values into a

SnapshotStateList

or can I feed the

LazyColumn

on the fly with the values? How would I do this?

Sanendak

09/02/2021, 10:21 PM

Hello guys! I have a question about conditional navigation. User can see start destination screen (Dashboard) and transition to sign in screen when isn't logged. Chain: 1. Check boolean from datastore flow in start destination screen (Dashboard) 2. In the Dashboard screen: if(isLogged) { Dashboard composable } else navigate to sign in How to fix this issue?

Napa Ram

09/03/2021, 5:48 AM

is there a way to handle life cycle as we are not using fragment and only one activity is there is project, i need inform view model 1. when compose screen created 2. when app go in background 3. when moving from one screen to another and when we are coming back to same screen 4. basically all lifecycle event

allan.conda

09/03/2021, 5:50 AM

We’re trying to render relative time accurately in Compose:

val displayTime = remember(message.createdTime) {
    DateUtils.getRelativeTimeSpanString(message.createdTime * 1_000).toString()
}
Text(displayTime)

When we refresh, we want to update the relative time text but it doesn’t a recomposition when the time value doesn’t change. Any idea how to handle this kind of scenario?

smit01

09/03/2021, 7:17 AM

Where can I find kotlin doc like documents for compose. There are some tutorials on YouTube but full fledged documents will help better learning it.

Lilly

09/03/2021, 12:19 PM

[SOLVED] I want to grant a permission by using

val requestPermissionLauncher = rememberLauncherForActivityResult(
        ActivityResultContracts.RequestPermission()
    ) { isGranted ->
        ...
    }

and

requestPermissionLauncher.launch(permission)

. I have discovered that

requestPermissionLauncher.launch(permission)

is responsible for opening the "android permission prompt" but triggers the above callback in the first run with
false
without waiting for a user action. When I click "Allow" btn the callback is triggered with
true
. Is the first run with false inteded? Do we have to suspend here and wait for a user action somehow? I would expect that the callback is only triggered when a button of the prompt is clciked.

ursus

09/03/2021, 12:45 PM

Has anyone seen an example of how should viewmodel+compose work with dagger? probably to provide the Screen composable woth viewmodel injected somehow?

Joey

09/03/2021, 12:46 PM

Is it possible with ScrollableTabRow to add spacing between tabs including the indicator?

tylerwilson

09/03/2021, 6:55 PM

I have a layout like so:

Box(fillMaxWidth) {
   Row(horizontalScroll) {
      items.forEach {
          Column(width(<boxWidth here>) {
          }
       }
   }
}

I want to dynamically change the inner column width to be the same as the ancestor box (it should be width of device), or some percentage (half or quarter). How can I reference the Box width in order to size the Column(s) properly? Thank you!

Carl Benson

09/03/2021, 7:17 PM

has anyone successfully resized a composable dialog destination using the insets-ui? how do I access the containing

Dialog

setDecorFitsSystemWindows

to false?

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josefdolezal

09/03/2021, 9:05 PM

Hey folks 🖖 , is there a way to animate

Buttons

colors based on

enabled

? What comes to my mind is to create my own class implementing

ButtonColors

which would then animate the color using

animateColorAsState

, but it seems a bit too verbose

adjpd

09/03/2021, 9:08 PM

In future, will the Android team continue to create new Android views and then the Jetpack Compose team mimics them, a la

TextInputLayout

and

TextField

? Moreover, is there a plan to make Jetpack Compose the primary view system for Android, or just an alternative?

Justin Yue

09/04/2021, 4:38 AM

I have a similar issue found in this thread where I am inserting a

LazyVerticalGrid

inside a

Column

with a scroll state, so I now know that I can't nest composables scrolling in the same direction. However, I'm only using

LazyVerticalGrid

since the cells can be adaptive, and I don't need its scroll functionality. Is there a way to create a composable that can replicate `LazyVerticalGrid`'s adaptive functionality and removing the scrolling?

rajesh

09/04/2021, 10:49 AM

How do I set min and max size (instead of using

fillMaxSize()

) of box having pinch to zoom ability? code is in thread.

Lorenzo Benevento

09/04/2021, 11:56 AM

How would you implement multiple `ModalBottomSheet`s? I found this article which explains how to do it using a

BottomSheetScaffold

but as soon as you try to do the same thing with a

ModalBottomSheetLayout

it throws

java.lang.IllegalArgumentException: The initial value must have an associated anchor.

because you are initializing it with a null value. If you just swap the two or more contents instead of setting a null value when you close the

ModalBottomSheet

it will work but it won't animate correctly.

Se7eN

09/04/2021, 1:53 PM

Probably not compose related, but how can I create an immutable copy of an object from a mutable one?

class Element {
    var position: Offset by mutableStateOf(...)
    var rotation: Float by mutableStateOf(...)
    ...
}

// Then I can do this:
val element = Element(...)
element.position = newPosition

I want to pass this

element

object to a composable but don't want it to be mutable. I can create a similar class for an immutable element but then I'd have to update the immutable class whenever I change the

Element

class. Is there something else I can do?

Fudge

09/04/2021, 2:39 PM

Is there a way to get the absolute layout position in

Layout

? the use case is to animate a component moving from one part of the screen to another.

rajesh

09/04/2021, 5:55 PM

Is there any way to decorate

TextField

BasicTextField

support decoration but lacks some of the features that

TextField

provides like leading icon. Is there any custom text field created by someone ?

adjpd

09/04/2021, 7:01 PM

The docs state that if you use the below as

rememberCoroutineScope().launch { }

then bugs may appear; since Compose can call the composables at any moment. In this scenario, or in any scenario, when is it likely to happen? I understand the concept but I can't think of any examples when this may actually happen.

LaunchedEffect(onTimeout) {
  delay(SplashWaitTime)
  onTimeout()
}

Colton Idle

09/05/2021, 2:34 AM

I have a column with horizontal padding

Column(modifier = Modifier.padding(horizontal = 16.dp)) {

every item need the horizontal padding except for 1 item in the col. Is there an easy way to "opt out"?

Colton Idle

09/05/2021, 4:01 AM

Not sure if I'm using flow + collectAsState correctly (it's my first time using a Flow, but a library I'm using exposes a flow, so I suppose it makes sense to use it) Code in thread

shahroz

09/05/2021, 8:54 AM

Whats the best approach to handle actions when it comes to Bottom Sheet? I am using Accompanist Navigation Material , if i navigate from one Composable to BottomSheet one, and in the bottom sheet I have couple of actions that i can perform, but i need to transmit the action callbacks upstream as well, what would be the best way to do this? cc @jossiwolf

bitkiller

09/05/2021, 3:04 PM

Trying to build a simple color picker in an AlertDialog. On some simple testings, the content (

text

) of the dialog is just

Column
  Box // clipped to Circle
  Text

But with this ^ the content is being place over the dialog's title.

Viktor Petrovski

09/05/2021, 8:21 PM

Hello, I’m having a weird issue which I can’t really understand the problem. To simplify things, I have two Composables, SplashScreen & HomeScreen. I need to make a network request on the SplashScreen and then navigate to HomeScreen when the endpoint succeeds. Code in thread 👇

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Title

Viktor Petrovski

09/05/2021, 8:21 PM

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Colton Idle

09/05/2021, 8:22 PM

@Viktor Petrovski can you edit your post to put the code in this thread please? https://kotlinlang.slack.com/archives/CJLTWPH7S/p1616265877303000

Viktor Petrovski

09/05/2021, 8:23 PM

Yes sure, sorry @Colton Idle

NavigationCode:

@Composable
fun Navigation() {
    val navController = rememberNavController()
    NavHost(navController = navController, startDestination = Screens.SplashScreen.route) {
        composable(Screens.SplashScreen.route) {
            val authViewModel = hiltViewModel<AuthViewModel>(it)
            SplashScreen(authViewModel, navController)
        }
        composable(Screens.Home.route) {
            val feedViewModel = hiltViewModel<FeedViewModel>()
            HomeFeedScreen(feedViewModel.state.value)
        }
    }
}

@Composable
fun SplashScreen(
    viewModel: AuthViewModel,
    navController: NavController
) {
    val state = viewModel.state.collectAsState()
    if (state.value.isSuccess) {
        navController.navigate(Screens.Home.route) {
            popUpTo(Screens.SplashScreen.route) {
                inclusive = true
            }
        }
    } else {
        // Render view...
    }

ViewModel:

@HiltViewModel
class AuthViewModel
@Inject constructor(private val useCase: CreateAnonymousUserUseCase) :
    ViewModel() {
    private val _state: MutableStateFlow<AnonAuthResponse> = MutableStateFlow(AnonAuthResponse())
    val state: StateFlow<AnonAuthResponse> = _state

    init {
        crateAnonUser()
    }

    private fun crateAnonUser() {
        viewModelScope.launch {
            useCase.createAnonymousUser().collect {
                _state.value = _state.value.copy(isSuccess = it.isSuccess, loading = it.loading)
            }
        }
    }
}

Added delay instead of the actual network request to maket things easier:

fun createAnonymousUser(): Flow<AnonAuthResponse> = flow {
    kotlinx.coroutines.delay(2500)
    emit(AnonAuthResponse(isSuccess = true))
}

If I remove the delay everything works fine, but when I add it it keeps on navigating to HomeScreen and re-rendering the SplashScreen. Thanks 🙏

➕ 1

Ian Lake

09/05/2021, 9:53 PM

You're calling

navigate()

as part of composition. That's always wrong (composition should never have side effects) - you'll end up calling

navigate()

on every frame of the animation between destinations, which is absolutely not what you want

But taking a step back, you should never have a splash screen destination as your start destination of your app as per the https://developer.android.com/guide/navigation/navigation-principles#fixed_start_destination

We've talked about login and these cases (and why they never work as the start destination of your app, particularly when you take into account process death and recreation and deep links) multiple times here in the past, such as: https://kotlinlang.slack.com/archives/CJLTWPH7S/p1626727460044100?thread_ts=1626726997.043700&cid=CJLTWPH7S

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Colton Idle

09/05/2021, 9:59 PM

Sorry to piggyback onto this, but Ian do you know if there's any sample that shows this sort of login scenario in compose. I basically have this working in my app because of all of your help, but I'm still"worried" that the way that I observe my loggedIn state and therefore triggering a move to the SignInScreen composable isn't right. Just trying to see if this is something that is already in some sample I can copy.

adjpd

09/05/2021, 10:42 PM

In the pathway tutorial, the final advanced segment, there's a section that deals with a splash screen.

Colton Idle

09/05/2021, 10:58 PM

Ooh. Thanks. Will take a look.

Viktor Petrovski

09/06/2021, 7:35 AM

Thanks @Ian Lake on your detailed response, will take a look at resources about setting up the start destination correctly. Soo back to my original question, when we want to navigate somewhere when a state changes ( in this case upon successfull log in) if we don’t want to call navigate from compose should we move the navigation logic in our ViewModel? I guess something like what Joe Brich is talking in his blog post https://medium.com/google-developer-experts/modular-navigation-with-jetpack-compose-fda9f6b2bef7?

Ian Lake

09/06/2021, 2:41 PM

No, you don't have to do all that - processing events is something you do in one of the effect methods, such as `LaunchedEffect`:

if (state.value.isSuccess) {
  // Use the value as the key
  // so that it only happens once
  LaunchedEffect(state.value) {
    // Call navigate here
  }
}

👍 1

Viktor Petrovski

09/06/2021, 2:42 PM

Oh Interesting, thanks! 🙌🙌

Colton Idle

09/06/2021, 5:24 PM

@Ian Lake why wouldn't it be

LaunchedEffect(state.value.isSuccess)

Viktor Petrovski

09/06/2021, 5:24 PM

I think it can, I believe it worked both ways for me

👍 1

Ian Lake

09/06/2021, 9:22 PM

Ideally you're using

by

and you wouldn't need the

.value

everywhere in the first place, but yes, I was assuming immutable objects where it wouldn't make a difference - the point is that the Launched effect would run just once for a given value change

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