kotlinlang #compose

How can I add a good looking fling behaviour to the red rect? All I see is the velocity tracker returning nonsense values (most of the times) - what am I missing?

Alex Vanyo

07/25/2022, 6:16 PM

One of the tricky parts here when looking at a specific implementation is how it comes down to naming and the associated expectations. When you have a single

MutableStateFlow<MyUiEvent>

, it reads like you are prolonging the handling of an event and keeping it in-flight for longer to be handled later. When you call

triggerEvent

, that sort of reads as “tell the UI to do this thing” (both of which are antipatterns as described in the article) Telling the UI to do something is not directly possible. If the UI isn’t available, then multiple calls to

triggerEvent

will clear out the previous “event” that was sent, without it being handled. Maybe that’s what you want, and maybe not, depending on the exact situation. Another weird issue that might happen because

block

is suspending: What happens if, while

block

is in the middle of running,

triggerEvent

is called again? I would try to turn

triggerEvent

into updating some state that more accurately reflects why you want to go to a different screen. Then, the

LaunchedEffect

reads more like “I am currently showing this

Composable

, and the state I am getting from the

ViewModel

says Y. Therefore, I should navigate somewhere else, and maybe tell the

ViewModel

I did so”

Sean McQuillan [G]

07/25/2022, 6:45 PM

Is anyone subclassing

Paragraph

class MyParagraph: Paragraph {...}

If so, can you share a bit more about what you're doing and why you chose not to wrap it?

class MyParagraphWrapper(val paragraph: Paragraph)

Jasmin Fajkic

07/25/2022, 7:05 PM

Hello. Maybe this question is already asked but really want to see how other people manage this. I need access to navcontroller deep down in child component. I do not want to do react thing “props drill” and that every piece of app knows for navcontroller event it does not need it. Is there any better approach to pass navcontroller deep down? Local composition?

Daniel Rotenberg

07/25/2022, 8:59 PM

Hi all, How can I create custom snack bar which used in scaffold? details in thread.

07/26/2022, 3:32 AM

I'm using a LazyColumn to display a list of videos but it loses its scroll position when navigating away from it to another screen. If i remove the loading indicator item then it remembers the scroll position properly

LazyColumn(
        modifier = Modifier
            .fillMaxSize()
            .padding(horizontal = 14.dp),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.spacedBy(8.dp)
    ) {
        items(videoListItems) { video ->
            if (video == null) return@items

            VideoCard(
                video = video,
                onClick = { onClickVideo(video.id) },
                onClickChannel = { onClickChannel(video.author!!.id) }
            )
        }

        item {
            videoListItems.loadState.apply {
                when (append) {
                    is LoadState.Loading -> {
                        CircularProgressIndicator(modifier = Modifier.padding(4.dp))
                    }
                    is LoadState.Error -> {
                        (append as LoadState.Error).error.printStackTrace()

                        Text("An error has occurred")
                    }
                    else -> Unit
                }
            }
        }
    }

Colton Idle

07/26/2022, 4:53 AM

I'm using the sample BottomNavigation bar and it's items like such:

BottomNavigation {
        items.forEachIndexed { index, item ->
            BottomNavigationItem(
                icon = { Icon(Icons.Filled.Favorite, contentDescription = null) },
                label = { Text(item) },
                selected = selectedItem == index,
                onClick = { selectedItem = index }
)}}

but on samsung devices (which are typically "zoomed in" out of the box) the text and icon overlap. If I try to increase the icon size (or add padding) then it grows larger than the bottomBar can support and so my icons are cut off. Surprisingly the BottomNavigationBar doesn't grow in height to support the larger text size or icon size. Is there any "right" way to fix this or should I look to implement an autosize text for the tab text?

allan.conda

07/26/2022, 7:31 AM

Reading about Compose Phases, I’m not sure about one thing. How does Scrollable list states avoid causing a recomposition (just remeasure/redraw)? I’m reading the source and saw a lot of mutableStates to track the scroll state, which should trigger recomposition in my understanding. But it seems to just call

remeasure

instead. Is there an optimization happening somewhere for scrolling?

Stylianos Gakis

07/26/2022, 9:46 AM

I want to get the size of a composable I’m currently in, is there a way to do this “inline” without doing something that moves this to the next frame? Say I got a state like this

var width by remember { mutableStateOf(0f) } // 0f or 0 or 0.dp not sure what I need yet
var height by remember { mutableStateOf(0f) }

Canvas can get you a size but can only set it on the next frame to the local state as I understand.

Canvas(Modifier.fillMaxSize()) {
  width = this.size.width
  height = this.size.height
}

OnGloballyPositioned also on the next frame

.onGloballyPositioned { it.size.height | width }

BoxWithConstraints uses subcomposition. My use case is trying to get the bounds of my Canvas in order to animate something that’s moving inside of it and make sure it’s not going outside. What other options do I have? Or is getting it from canvas and saving it to a local state the way to go? Also what if I was not using a Canvas anyway, what other alternatives are there?

Lukasz Kalnik

07/26/2022, 12:42 PM

Is there a dropdown spinner, showing the currently selected option when collapsed and with an expand/collapse arrow?

Programmistich

07/26/2022, 3:44 PM

Any modifier for hold element?

combinedClickable()

have onClick/onDouble/onLong but dont have onHold

Lokik Soni

07/26/2022, 6:00 PM

Hi all I am collecting flow in compose using collectAsState() But don't know how to make it lifecycle aware or collectAsState() is already lifecycle aware. In compose screen

val isAlarmOn by viewModel.alarmBtnState.collectAsState()

In ViewModel

val alarmBtnState = isAlarmActivated(Unit).map {
    it.successOr(DEF_VAL_ALARM_ACTIVATED)
}.stateIn(viewModelScope, WhileViewSubscribed, DEF_VAL_ALARM_ACTIVATED)

Chuck Stein

07/26/2022, 7:45 PM

I understand that animating insertions/deletions into a

LazyList

is still under development, but what's the recommendation for animating insertions/deletions into a regular

Column

Row

Raymond

07/26/2022, 8:09 PM

Hi Guys! Any news about composable function references in kotlin?

deviant

07/27/2022, 10:54 AM

hey guys is it possible to use

compose.material

and

compose.material3

in same project (same screen)?

Arkadii Ivanov

07/27/2022, 10:55 AM

🔥 https://twitter.com/JorgeCastilloPr/status/1552169372193538049

Ji Sungbin

07/27/2022, 1:18 PM

Hi, How can I use the

liveLiterals

plugin option? When I try to apply it, I get this error: Multiple values are not allowed for plugin option androidx.compose.compiler.plugins.kotlin:liveLiterals.

freeCompilerArgs += [
        "-P",
        "plugin:androidx.compose.compiler.plugins.kotlin:liveLiterals=false"
]

jasu

07/27/2022, 1:35 PM

I’m using

compose-hilt-navigation

and in one of the screens i’m using BackHandler(onBack = someCall). Somecall is not getting called any idea? inshort: back handler is not working

Rafs

07/27/2022, 5:16 PM

Do we have any official or decent flow layout libraries in compose? I remember there used to be

FlowRow/Column

but they aren’t available anymore.

Ale Stamato

07/27/2022, 5:17 PM

Compose 1.2 is stable https://android-developers.googleblog.com/2022/07/jetpack-compose-1-2-is-now-stable.html

Benjamin Deroche

07/27/2022, 7:21 PM

Are

ArrowCircleLeft

and

ArrowCircleRight

icons missing from Android Compose? I use all 4 of them (left, top, right, bottom) in my Kotlin Multiplatform app for Android and JVM. Android Studio show no error, the JVM app compile and run just fine, but the Android app fail to compile because I get an unresolved reference for left and right arrows

itnoles

07/27/2022, 8:02 PM

I like how compose compiler made a huge jump from 1.3.0 beta 1 to 1.3.0 rc 1

Harold Scissors

07/27/2022, 8:28 PM

Couldn't find an answer by searching,, was

repeatOnLifecycle

removed from

lifecycle-runtime-ktx

? I'm looking to solve an issue where we need link

produceState

based on lifecycle events within a composable function.

Harold Scissors

07/27/2022, 11:23 PM

Somewhat related follow-up question to the above: what would be the best way have a suspend fun called on each

Lifecycle.State.RESUMED

? I tried this which was posted before on similar threads but it seems because

produceState

conflates

value

, only the first value causes recomposition. So, on the first resume, we see the value, on the second (if it is the same) we see nothing. Ideally, we'd want to see it on every

RESUMED

even if it is the same.

oianmol

07/28/2022, 3:51 AM

Hi Folks! We Android Devs @MutualMobile are back again with a new Pixel-Perfect Compose Project after the Slack android clone, We present #Discord #jetpackcompose clone, It's a but here's a sneak peek. https://github.com/Anmol92verma/DiscordJetpackCompose

Tin Tran

07/28/2022, 4:34 AM

Is it a good practice passing

ModalBottomSheetState

to ViewModel?

Ali Khaleqi Yekta

07/28/2022, 5:46 AM

message has been deleted

Kazik

07/28/2022, 6:23 AM

Hi Guys. Is there any way to detect when bottom sheet is dismissed? For now I subscribe to navController’s current back stack entry flow inside bottom sheet, but it feels like hacky solution.

LaunchedEffect(Unit) {
  navController.currentBackStackEntryFlow
    .filter { it.destination.route == parentRoute }
    .collect { onClose() }
}

07/28/2022, 6:36 AM

How can I use scroll behavior for a top app bar and also the pull to refresh accompanist library together?

Arun Joseph

07/28/2022, 6:52 AM

Is there any known issue with

accompanist-navigation-animation

and rotation, I observe that the obtained

viewmodel

leaks when transitions between screens, when each screen forces certain orientation. Sample code in thread.

Title

Arun Joseph

07/28/2022, 6:52 AM

Is there any known issue with

accompanist-navigation-animation

and rotation, I observe that the obtained

viewmodel

leaks when transitions between screens, when each screen forces certain orientation. Sample code in thread.

class AppActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            SampleNavHost()
        }
    }
}

@Composable
fun SampleNavHost() {
    val navController = rememberAnimatedNavController()
    AnimatedNavHost(
        navController = navController,
        startDestination = "ScreenA",
    ) {
        composable("ScreenA") {
            val viewModel: ScreenAViewModel = viewModel()
            val context = LocalContext.current
            LaunchedEffect(key1 = Unit) {
                context.tryFindActivity()?.requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT
            }
            Button(
                onClick = {
                    navController.popBackStack()
                    navController.navigate("ScreenB")
                },
                content = {
                    Text("Navigate to ScreenB")
                }
            )
        }
        composable("ScreenB") {
            val viewModel: ScreenBViewModel = viewModel()
            val context = LocalContext.current
            LaunchedEffect(key1 = Unit) {
                context.tryFindActivity()?.requestedOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE
            }
            Button(
                onClick = {
                    navController.popBackStack()
                    navController.navigate("ScreenA")
                },
                content = {
                    Text("Navigate to ScreenA")
                }
            )
        }
    }
}

class ScreenAViewModel : ViewModel() {
    override fun onCleared() {
        println("onCleared $this")
        super.onCleared()
    }
    init {
        println("onCreated $this")
    }
}

class ScreenBViewModel : ViewModel() {
    override fun onCleared() {
        println("onCleared $this")
        super.onCleared()
    }
    init {
        println("onCreated $this")
    }
}

fun Context.tryFindActivity(): Activity? {
    var context = this
    while (context is ContextWrapper) {
        if (context is Activity) return context
        context = context.baseContext
    }
    return null
}

I get the below when I use just the

NavHost

2022-07-28 08:38:22.523 14687-14687 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenAViewModel@30e43db
2022-07-28 08:38:25.694 14687-14687 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenBViewModel@7939130
2022-07-28 08:38:26.428 14687-14687 System.out                                           I  onCleared com.tomtom.roadcaptain.home.presentation.ScreenAViewModel@30e43db
2022-07-28 08:38:45.367 14687-14687 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenAViewModel@a2852cc
2022-07-28 08:38:46.084 14687-14687 System.out                                           I  onCleared com.tomtom.roadcaptain.home.presentation.ScreenBViewModel@7939130

whereas with

AnimatedNavHost

2022-07-28 08:48:02.868 15669-15669 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenAViewModel@66faa0b
2022-07-28 08:48:05.696 15669-15669 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenBViewModel@5b834d9
2022-07-28 08:48:14.797 15669-15669 System.out                                           I  onCreated com.tomtom.roadcaptain.home.presentation.ScreenAViewModel@1ef23a5

I filed bug at https://github.com/google/accompanist/issues/1265

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