kotlinlang #compose

@Composable
fun Payment(
    price: Double,
    onResult: (Int, PaymentResponse) -> Unit
) {
    val launcher = rememberLauncherForActivityResult(ActivityResultContracts.StartActivityForResult()) {
            onResult(RC_PAY, appNotFoundError ?: handlePaymentResult(it.data))
    }
    launcher.launch(preparePaymentIntent(price))
}

How do I handle the exception caused by

launcher.launch

when there is not Acitivity found to handle the

Intent

passed to

launch

Kata

03/17/2022, 1:18 PM

When using

Paging

with custom unique keys(UUID) and

LazyColumn

I found the following issue: When I scroll through a bigger list(with 150 elements, paging 30) too fast then the app crashes with:

"Key $slotId was already used. If you are using LazyColumn/Row please make sure you provide a unique key for each item."

Issue is coming from SubcomposeLayout.kt line

. Now if I scroll though the list really slowly then everything works fine. Once everything is loaded and I scroll through it fast then there is no issue. Anybody has an idea what could be the issue? Is this maybe a bug inside compose? What I found is by adjusting the paging size to something smaller the crash happens earlier and when modifying the paging to something bigger than the list itself then the crash is not happening. I tried is with compose version

1.1.0

and also with

1.2.0-alpha05

👀 1

Slackbot

03/17/2022, 1:19 PM

This message was deleted.

skwalking

03/17/2022, 2:33 PM

Any way to use Google Play In-App Review API in jetpack compose based app ?

Mohan

03/17/2022, 5:09 PM

22-03-17-22-38-15.mp4

Mohan

03/17/2022, 5:10 PM

Text field at the bottom of the list doesn't get focus, keyboard closes as soon as clicked on the textfield., If anyone has faced this issue please help.

Robert Menke

03/17/2022, 7:49 PM

Is there a way with coil-compose to specify that you want the placeholder image to render at a different size than the real image?

jonc

03/17/2022, 11:26 PM

Is it possible to access the size of a drawing environment? In my specific use case I'm applying the

graphicsLayer

modifier to an

Image

. I need the size of the image respective to content scale in order to implement some customized gestures. I've tried

onSizeChanged

and

onGloballyPositioned

but those seem to be used for the layouts rather than graphics so it isn't called when transformations are made through

graphicsLayer

Lance Gao

03/18/2022, 2:07 AM

Hi there, how can I show a

Box{}

and start with a fade-in animation?

Zoltan Demant

03/18/2022, 5:11 AM

Back in the day, enums followed the

VERY_BOLD

naming pattern, since compose they (and a lot of other variables) follow a

MuchSofterPattern

. Im curious about how you manage any type of consistency between the two in your projects? Personally, I prefer the latter - but refactoring isnt very simple when the old style enums are part of external datasets, json structures, etc. I feel liek Im stuck with

UPPER_CASE

and

BeautifulCase

(sorry, I couldnt find the actual appropiate names for them) and I rarely know when to use which as a result.

Abhilash

03/18/2022, 9:31 AM

I know there are a few of naming conventions for functions in compose. But is there any naming conventions I should follow for naming packages in compose?

thelumiereguy

03/18/2022, 10:32 AM

Are there any differences between place() and placeRelative() other than RTL support?

🇳🇴 2

Fabio

03/18/2022, 1:39 PM

I started adopting Compose 1.1.1 in an existing Android app but I'm facing very weird behavior when trying to limit input in a

TextField

to decimal numbers. I just posted a question on StackOverflow with the full details, but I could also post them here if you prefer. The TL;DR is that even if I do not update my state in response to the

onValueChange

callback (or if I just set the previous value and ignore the new one), the text I get in the next

onValueChange

still includes the changes I rejected.

Bradleycorn

03/18/2022, 3:22 PM

We’re converting a Fragment based app over to Compose. It’s got quite a few Fragments. During this transition period, I know I can use the

AndroidViewBinding

Composable to inflate a

FragmentContainerView

with a Fragment and show it within composable “screen”. So far though, it seems like I have to create a wrapper xml layout resource with a

FragmentContainerView

for every fragment. I was hoping to find a way to just define a single xml layout resource (compose_fragment_container.xml) and write a composable that uses it with

AndroidViewBinding

to load an arbitrary Fragment. But so far no luck. Anyone know a way to do this? My current (not working) code in the 🧵

Marko Novakovic

03/18/2022, 4:07 PM

I have interactive preview enabled but clicks are not working at all. button click shows ripple effect and effect is stuck in the middle of animation and just stays like that. multiple clicks and ripples just stack

colintheshots

03/18/2022, 7:47 PM

I need to keep some buttons onscreen underneath a textfield while my IME keyboard is visible. I know all the tricks with Accompanist Insets (and the new insets in Compose 1.2.0-alpha), but none of them seem to be working for me. When I use

Modifier.imePadding

Modifier.navigationBarsWithImePadding

, the UI elements are scrolled completely offscreen and I’m left with a blank space where they were. I was able to workaround the issue by giving my textfield a weight of 1f and this keeps the buttons onscreen above the keyboard and below the textfield, but I can’t use this on screens with more than one textfield. Are there any alternatives to Modifier.weight(1f) that will work better here?

Robert Menke

03/18/2022, 9:56 PM

I can’t seem to find an explanation of the

contentType

parameter for

items

that I can understand. Let’s say I have a

LazyColumn

where each item is a

FooItem

. What am I supposed to be supplying to

contentType

fun items(
        count: Int,
        key: ((index: Int) -> Any)? = null,
        contentType: (index: Int) -> Any? = { null },
        itemContent: @Composable LazyItemScope.(index: Int) -> Unit
    ) {
        error("The method is not implemented")
    }

Mjahangiry75

03/19/2022, 8:39 AM

Is there a way to have multi

BottomSheet

dialog in a screen? just like

Dialog

nuhkoca

03/19/2022, 3:33 PM

Hello I have a setup below for different views based on different states. Views for

Success

and

Error

states already work as expected because they aren’t centered on the screen but

LoadingView

should be centered instead but it is always placed on top. How do I fix this? Thank you.

...
Scaffold(topBar = topBar) {
    Box(
        modifier = Modifier
            .padding(it)
            .verticalScroll(rememberScrollState())
    ) {
        when (collectionState) {
            CollectionState.Loading -> LoadingView()
            is CollectionState.Success -> {
                ScreenView(
                    collection = collectionState.collection,
                    onWatchlistItemClick = onWatchlistItemClick,
                    onDisclaimerTextClicked = onDisclaimerTextClicked
                )
            }
            CollectionState.Error -> ErrorView(onTryAgainClicked = onTryAgainClicked)
        }
    }
}
...

@Composable
private fun LoadingView() {
    Box(
        modifier = Modifier.fillMaxSize(),
        contentAlignment = Alignment.Center
    ) {
        CircularProgressIndicator()
    }
}

harry.singh

03/19/2022, 10:23 PM

Hey all! I'm collecting a

Channel(Channel.BUFFERED)

as a flow in a Composable function but I'm only ever seeing the latest element and missing all of the elements before the latest one. I've added all of the code here. I debugged

collectAsState

and I'm seeing all of the elements in the

produceState

composable function but not in my composable function. Any ideas why this might be happening?

andrew

03/20/2022, 12:32 AM

Had some help from @romainguy, wrangling filament for this, still very rough but I wrote composable wrappers for some imperative APIs for Filament's model viewer. Also these are real IoT devices I'm triggering in the office around 1k miles away in Philadelphia. I'm in Florida, and I hope no one wonders why a light is going on/off 😂

screen-20220319-202637.mp4

Android75

03/20/2022, 4:39 AM

Android75

03/20/2022, 6:05 AM

Hi I’m changing my app to compose vesion. I have to develop a classinc wizard such as this..

Android75

03/20/2022, 6:05 AM

to swipe 2-3 “pages” what can i use ?

Zach Klippenstein (he/him) [MOD]

03/20/2022, 4:52 PM

Does passing null to

leadingIcon

work?

03/20/2022, 10:55 PM

I'm using this library https://github.com/raamcosta/compose-destinations, is it possible to get a screen that can be collapsed down but displayed on top of another screen? Like the collapsible player in the Youtube app

FunkyMuse

03/20/2022, 11:05 PM

Hey guys, is there equivalent of splitMotionEvents from RecyclerView for LazyColumn/Row?

mcpiroman

03/21/2022, 8:54 AM

Are there any plans to move Compose project outside of androidx repository / generally decouple it from android(x) / merge with Jetbrains' fork? I think as a whole Compose is inherently more multiplatform than android, although I'm not sure how complicated would it be to setup android dependencies/workflow in that case. Is https://issuetracker.google.com/issues/187071114 relevant to above, or is it only about final binaries, no matter how produced? I'm mainly asking because it's currently hard to play with and contribute given the setup of AOSP, especially for non-android parts.

althaf

03/21/2022, 10:21 AM

hi, when using this pattern

class LoginViewModel : ViewModel() {

    val registeredUsers = mutableStateListOf<UIRegisteredUser>()

in the view model 1. Is there way to protect this registeredUsers list from updating the object values from other than view model ? I'm tryting to avoid accidental modification these values from out side view model, trying to keep vm as single source of truth.

althaf

03/21/2022, 10:23 AM

here any one access to view model will be able to modify this directly. Which live data i use this pattern

private val _quickLinks = MutableLiveData<List<UIQuickLink>>()
val quickLink: LiveData<List<UIQuickLink>> = _quickLinks

So that, quickLink access are only observed than posted with new values from UI, here update to quickLink happens from only view model

Title

althaf

03/21/2022, 10:23 AM

here any one access to view model will be able to modify this directly. Which live data i use this pattern

private val _quickLinks = MutableLiveData<List<UIQuickLink>>()
val quickLink: LiveData<List<UIQuickLink>> = _quickLinks

So that, quickLink access are only observed than posted with new values from UI, here update to quickLink happens from only view model

f.babic

03/21/2022, 10:24 AM

You can do the same for state, just expose a

State

instead of a

MutableState

using a second property. You could also do it with a function instead of a property

althaf

03/21/2022, 10:32 AM

@f.babic, is this how we do it ? I understood your point, however some thing is missing, this isn't working

val _registeredUsers = mutableStateListOf<UIRegisteredUser>()

val registeredUser: State<UIRegisteredUser> = _registeredUsers

I think this is how we have to do is in case of mutableStateList

val _registeredUsers = mutableStateListOf<UIRegisteredUser>()
val registeredUser: SnapshotStateList<UIRegisteredUser> = _registeredUsers

SnapshotStateList

Is mutable 😕

f.babic

03/21/2022, 10:36 AM

Is there a reason why you use

mutableStateListOf

instead of

mutableStateOf

? We're using the latter in our code and seems to work fine, haven't had issues per se.

althaf

03/21/2022, 10:50 AM

private val _registeredUsers = mutableStateOf<List<UIRegisteredUser>>(value = listOf())
val registeredUser: State<List<UIRegisteredUser>> = _registeredUsers

This above appears to work , however following use case we are not able to accomplish with above approach, where as with mutableStateListOf() these worked fine, however, object became insecure

init {
    _registeredUsers.value.toMutableStateList().addAll(mockRegisteredUsers)
    
}

fun onUserSelected(user: UIRegisteredUser) {
    viewModelScope.coroutineContext.run {
        _registeredUsers.value.toMutableStateList().let { userList ->
            userList.find { it.isSelected }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = false))
                }
            }

            userList.find { it == user }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = true))
                }
            }
        }
    }
}

f.babic

03/21/2022, 10:55 AM

Oh okay that makes sense - in that case you'd come back to the same thing if you went that way. I mean, instead of:

_registeredUsers.value.toMutableStateList().addAll(mockRegisteredUsers)

You could have:

_registeredUsers.value = _registeredUsers.value + mockRegisteredUsers

Basically, instead of havign a mutable list that can be changed anywhere, you use immutable lists but make sure to add/remove items from the given list and producing a new list instead. That gives you control in the ViewModel of whatever you want to do, but the rest of the world won't be able to mutate incorrectly

althaf

03/21/2022, 10:57 AM

@f.babic i got it working with your approach, so these are the changes,

private val _registeredUsers = mutableStateOf<ArrayList<UIRegisteredUser>>(value = arrayListOf())
val registeredUsers: State<List<UIRegisteredUser>> = _registeredUsers

I'm using ArrayList now

fun onUserSelected(user: UIRegisteredUser) {
    viewModelScope.coroutineContext.run {
        _registeredUsers.value.let { userList ->
            userList.find { it.isSelected }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = false))
                }
            }

            userList.find { it == user }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = true))
                }
            }
        }
    }
}

this also work fine

however @f.babic there is a catch , when the onUserSelected is called, recomposition is not happening

any input on this ?

f.babic

03/21/2022, 11:00 AM

This is because you're taking the list of items form the State, copying it and updating it in that instance. You should always push the new state/list to the property like:

_registeredUsers.value = newValue

when you mutate the list within those

find

calls, you need to make sure to push the new state to the UI

althaf

03/21/2022, 11:09 AM

@f.babic sorry to bother you this way 😢 that didn't work either UI is observing from composable for registeredUser

SelectLoginUsersScreenContent(registeredUsers = loginViewModel.registeredUsers.value, onUserSelected = onUserSelected)

fun onUserSelected(user: UIRegisteredUser) {
    viewModelScope.coroutineContext.run {
        _registeredUsers.value.let { userList ->
            userList.find { it.isSelected }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = false))
                }
            }

            userList.find { it == user }?.let {
                userList.indexOf(it).also { index ->
                    userList.remove(it)
                    userList.add(index, it.copy(isSelected = true))
                }
            }
            _registeredUsers.value = userList
        }
    }
}

See that last line i 'm even manually setting _registeredUser.value

f.babic

03/21/2022, 11:19 AM

Could you try doing something like:

val registeredUsers by loginViewModel.registeredUsers

SelectLoginUsersScreenContent(registeredUsers = registeredUsers, onUserSelected = onUserSelected)

Basically the way we expose state in our VMs is the following:

private var threadMessagesState: MessagesState by mutableStateOf(MessagesState())

And then we just fetch it using an exposed property or something

althaf

03/21/2022, 11:31 AM

val registeredUsers by loginViewModel.registeredUsers

SelectLoginUsersScreenContent(
    registeredUsers = registeredUsers,
    onUserSelected = onUserSelected
)

😭 didnt work @f.babic

Albert Chang

03/21/2022, 11:42 AM

Why can’t you just do this?

private val _registeredUsers = mutableStateListOf<UIRegisteredUser>()
val registeredUsers: List<UIRegisteredUser> = _registeredUsers

☝️ 2

althaf

03/21/2022, 11:44 AM

i need registeredUsers to trigger recomposing when value changes

will it be possible if we use registeredUsers: List<UIRegisteredUser>?

Albert Chang

03/21/2022, 11:45 AM

Yep. As long as a snapshot state is read, even if not directly, it will trigger recomposition when it changes.

althaf

03/21/2022, 11:48 AM

💥🥳

@Albert Chang @f.babic thank you , it worked

private val _registeredUsers = mutableStateListOf<UIRegisteredUser>()
val registeredUsers: List<UIRegisteredUser> = _registeredUsers

❤️ 1

View count: 4