Scroll all screen with a lazy column and paging library inside - android

I'm new to Jetpack Compose and I'm not quite sure how to do what I need. In the screen below, I want to scroll the whole screen and not just the list at the bottom and when the scroll reaches the end of the list below, it still applies the paging library and goes to get more elements. I managed to get the Paging Library to work and the scroll in the list below too, but I can't make the rest of the page elements scroll as well - this is because only the list has scroll and not the rest of the page. Whenever I'm trying to do that, I get the following crash:
Vertically scrollable component was measured with an infinity maximum height constraints, which is disallowed. One of the common reasons is nesting layouts like LazyColumn and Column(Modifier.verticalScroll()). If you want to add a header before the list of items please add a header as a separate item() before the main items() inside the LazyColumn scope. There are could be other reasons for this to happen: your ComposeView was added into a LinearLayout with some weight, you applied Modifier.wrapContentSize(unbounded = true) or wrote a custom layout. Please try to remove the source of infinite constraints in the hierarchy above the scrolling container.
and I don't really know why.
I leave you the code below and two screenshots: the first is the current state, where I can only scroll through the list. The second is what I intend, which is to scroll the entire page.
#Edit: I was able to implement all screen scroll with fixed height on the children lazy column, but that is not what I want.
#Composable
#ExperimentalFoundationApi
private fun MainActivityLayout(navController: NavHostController) {
LazyColumn(
modifier = Modifier
.paint(
painter = painterResource(id = R.drawable.main_background),
contentScale = ContentScale.FillBounds
)
.fillMaxSize(),
horizontalAlignment = Alignment.CenterHorizontally
) {
item {
HeightSpacer(Dimen40)
Image(
painter = painterResource(id = R.drawable.ic_clearjobs_logo_2x),
contentDescription = null
)
HeightSpacer(Dimen47)
Navigation(navController = navController)
}
}
}
#Composable
#ExperimentalFoundationApi
fun JobOpeningsScreen(viewModel: JobOpeningsViewModel = hiltViewModel()) {
val uiState by viewModel.uiState.collectAsState()
Column {
ClearJobsScreenTitle(
lightTitle = stringResource(id = R.string.job_openings_light_title),
boldTitle = stringResource(id = R.string.job_openings_bold_title)
)
HeightSpacer(Dimen60)
Row {
CategoryButton()
WidthSpacer(Dimen2)
OrderByButton()
}
HeightSpacer(Dimen30)
SearchTextField()
HeightSpacer(Dimen60)
when (uiState) {
is BaseViewState.Data -> JobOpeningsContent(
viewState = uiState.cast<BaseViewState.Data<JobOpeningsViewState>>().value
)
is BaseViewState.Loading -> {
LoadingView()
}
else -> {}
}
LaunchedEffect(key1 = viewModel, block = {
viewModel.onTriggerEvent(JobOpeningsEvent.LoadJobOffers)
})
}
}
#Composable
fun JobOpeningsContent(viewState: JobOpeningsViewState) {
val pagingItems = rememberFlowWithLifecycle(viewState.pagedData).collectAsLazyPagingItems()
SwipeRefresh(
state = rememberSwipeRefreshState(
isRefreshing = pagingItems.loadState.refresh == LoadState.Loading
),
onRefresh = { pagingItems.refresh() },
indicator = { state, trigger ->
SwipeRefreshIndicator(
state = state,
refreshTriggerDistance = trigger,
scale = true
)
},
content = {
LazyColumn(
modifier = Modifier.width(Dimen320),
verticalArrangement = Arrangement.spacedBy(Dimen30)
) {
items(pagingItems.itemCount) { index ->
pagingItems[index]?.let {
JobOpeningsRow(dto = it)
}
}
if (pagingItems.loadState.append == LoadState.Loading) {
item {
Box(
Modifier
.padding(24.dp)
) {
CircularProgressIndicator(Modifier.align(Alignment.Center))
}
}
}
}
}
)
}

I found the solution to this problem, although it is not 100% and in terms of code it is not as good as I would like.
The error speaks for itself, we can't have infinite vertical scroll, Jetpack Compose doesn't allow it. I had the option of putting a fixed height on the Lazy Column of my list, but it wasn't what I wanted and it didn't work properly. The solution was to put everything inside a single LazyColumn and remove the Column from MainActivity, using a Box element and contentAlignment. I leave you below the final code that I used to solve the problem.
MainScreen function that before was MainActivityLayout function:
#Preview
#Composable
#ExperimentalFoundationApi
fun MainScreen() {
val navController = rememberNavController()
val topLevelDestinations = listOf(
NavigationItem.JobOpenings,
NavigationItem.Profile,
NavigationItem.About
)
val isTopLevelDestination =
navController
.currentBackStackEntryAsState()
.value
?.destination
?.route in topLevelDestinations.map { it.route }
val backStackEntryState = navController.currentBackStackEntryAsState()
Scaffold(
bottomBar = {
if (isTopLevelDestination) {
BottomNavBar(
navController = navController,
backStackEntryState = backStackEntryState,
bottomNavItems = topLevelDestinations
)
}
}
) {
Box(
modifier = Modifier
.paint(
painter = painterResource(id = R.drawable.main_background),
contentScale = ContentScale.FillBounds
)
.fillMaxSize(),
contentAlignment = Alignment.Center
) {
Navigation(navController = navController)
}
}
}
New JobOpenings fun that is mixed with old JobOpeningsContent function:
#Composable
#ExperimentalFoundationApi
fun JobOpeningsScreen(viewModel: JobOpeningsViewModel = hiltViewModel()) {
val uiState by viewModel.uiState.collectAsState()
when (uiState) {
is BaseViewState.Data -> {
val pagedData = uiState.cast<BaseViewState.Data<JobOpeningsViewState>>().value.pagedData
val pagingItems = rememberFlowWithLifecycle(pagedData).collectAsLazyPagingItems()
SwipeRefresh(
state = rememberSwipeRefreshState(
isRefreshing = pagingItems.loadState.refresh == LoadState.Loading
),
onRefresh = { pagingItems.refresh() },
indicator = { state, trigger ->
SwipeRefreshIndicator(
state = state,
refreshTriggerDistance = trigger,
scale = true
)
},
content = {
LazyColumn(
modifier = Modifier
.width(Dimen320),
verticalArrangement = Arrangement.spacedBy(Dimen30)
) {
item {
ScreenHeader(
lightTitle = stringResource(id = R.string.job_openings_light_title),
boldTitle = stringResource(id = R.string.job_openings_bold_title)
)
HeightSpacer(Dimen60)
Row {
CategoryButton()
WidthSpacer(Dimen2)
OrderByButton()
}
HeightSpacer(Dimen30)
SearchTextField()
HeightSpacer(Dimen60)
}
items(pagingItems.itemCount) { index ->
pagingItems[index]?.let {
JobOpeningsRow(dto = it)
}
}
if (pagingItems.loadState.append == LoadState.Loading) {
item {
Box(Modifier.padding(Dimen24)) {
CircularProgressIndicator(Modifier.align(Alignment.Center))
}
}
}
}
}
)
}
is BaseViewState.Loading -> LoadingView()
else -> {}
}
LaunchedEffect(key1 = viewModel, block = {
viewModel.onTriggerEvent(JobOpeningsEvent.LoadJobOffers)
})
}
#ExperimentalFoundationApi
#Preview
#Composable
fun JobOpenings() {
JobOpeningsScreen()
}
Problems that I found with this solution:
LoadingView appears at the top of the screen instead at the top of the list.
If anyone has any suggestion to improve this, I am open to it. This works perfectly with Paging Library + Swipe Refresh (Accompanist) and full page scroll.

Related

Rearranging LazyColumn Recompositing issues

I have a LazyColumn that takes a list from my Room database.
I am creating a button that can re arrange the list from newest first, or oldest first. The problem I'm having is that when I rearrange the list, the LazyColumns view drops to the bottom of the LazyColumn. I do NOT want the list view to change during the list change. I am using a key for the list which is where I suspect my issue is coming from.
When I disable the key, this is not an issue however, that comes with its own issues so I cannot disable it permanently. Does anyone know and easy fix to this?
my composable ->
#OptIn(ExperimentalFoundationApi::class)
#Composable
fun MainScreen(navController: NavController, notesViewModel: NotesViewModel) {
val myUiState by notesViewModel.uiState.collectAsState()
val multiDelete = remember { mutableStateListOf<Note>() }
val scope = rememberCoroutineScope()
val state = rememberLazyListState()
Surface {
Column {
Row {
FloatingActionButton(onClick = { notesViewModel.updateStates(true) }) {}
FloatingActionButton(onClick = { notesViewModel.updateStates(false) }) {}
NewNote(navController)
if(multiDelete.isNotEmpty()){
FloatingActionButton(
onClick = {
scope.launch {
notesViewModel.deleteSelected(multiDelete)
delay(50)
multiDelete.clear()
}
}
) { Image(imageVector = Icons.Filled.Delete, contentDescription = "this") }
}
}
LazyColumn(
state = state,
horizontalAlignment = Alignment.CenterHorizontally,
contentPadding = PaddingValues(vertical = 10.dp),
verticalArrangement = Arrangement.spacedBy(10.dp),
modifier = Modifier
.background(color = Color.Gray)
.fillMaxSize()
.focusRequester(FocusRequester()),
) {
items(
if(myUiState.toggle) myUiState.allNotes else myUiState.allNotes.reversed(),
key = {notes -> notes.uid!!}
) {
notes ->
Column(
modifier = Modifier.animateItemPlacement()
) {
ConsoleCards(
note = notes,
onDeleteClick = {
notesViewModel.delete(notes)
},
onLongPress = {
if(multiDelete.contains(notes)) multiDelete.remove(notes) else multiDelete.add(notes)
},
onEditClick = {
notesViewModel.uid(notes.uid!!)
notesViewModel.header(notes.header!!)
notesViewModel.note(notes.note!!)
navController.navigate(route = PageNav.AddNote.name)
}
)
}
}
}
}
}
}
This may not be the best solution. Theres also a similar issue like this and this
itemsIndexed(
items = checkItems.sortedBy { it.checked.value },
key = { index, item -> if (index == 0) index else item.id }
) { index, entry ->
...
}

PullRefreshIndicator overlaps with ScrollableTabRow

I'm starting to learn about Jetpack Compose. I put together this app where I explore different day-to-day use cases, each of the feature modules within this project is supposed to tackle different scenarios.
One of this feature modules – the chatexample feature module, tries to implement a simple ViewPager where each of the pages is a Fragment, the first page "Messages" is supposed to display a paginated RecyclerView wrapped around a SwipeRefreshLayout. Now, the goal is to implement all this using Jetpack Compose. This is the issue I'm having right now:
The PullRefreshIndicator that I'm using to implement the Pull-To-Refresh action works as expected and everything seems pretty straightforward so far, but I cannot figure out why the ProgresBar stays there on top.
So far I've tried; Carrying on the Modifier from the parent Scaffold all the way through. Making sure I explicitly set the sizes to fit the max height and width. Add an empty Box in the when statement - but nothing has worked so far, I'm guessing I could just remove the PullRefreshIndicator if I see that the ViewModel isn't supposed to be refreshing, but I don't think that's the right thing to do.
To quickly explain the Composables that I'm using here I have:
<Surface>
<Scaffold> // Set with a topBar
<Column>
<ScrollableTabRow>
<Tab/> // Set for the first "Messages" tab
<Tab/> // Set for the second "Dashboard" tab
</ScrollableTabRow>
<HorizontalPager>
// ChatExampleScreen
<Box> // A Box set with the pullRefresh modifier
// Depending on the ChatExamleViewModel we might pull different composables here
</PullRefreshIndicator>
</Box>
// Another ChatExampleScreen for the second tab
</HorizontalPager>
</Column>
<Scaffold>
</Surface>
Honestly, I don't get how the PullRefreshIndicator that is in a completely different Composable (ChatExampleScreen) gets to overlap with the ScrollableTabRow that is outside.
Hope this makes digesting the UI a bit easier. Any tip, advice, or recommendation is appreciated. Thanks! 🙇
Edit: Just to be completely clear, what I'm trying to achieve here is to have a PullRefreshIndicator on each page. Something like this:
On each page, you pull down, see the ProgressBar appear, and when it is done, it goes away, within the same page. Not overlapping with the tabs above.
A comparatively easier solution in my case was to simply give the Box that contains my vertically scrollable Composable and my PullRefreshIndicator a zIndex of -1f:
Box(Modifier.fillMaxSize().zIndex(-1f)) {
LazyColumn(...)
PullRefreshIndicator(...)
}
And that already did the trick for me. I have a very similar setup to the OP, a Scaffold containing a ScrollableTabRow and a HorizontalPager with refreshable lists on the individual tabs.
I want to leave my first answer as I feel it will still be useful to future readers, so heres another one you might consider.
One of the Box in the tabs has a scroll modifier though, because according to the Accompanist Docs and the actual functionality.
… The content needs to be 'vertically scrollable' for SwipeRefresh()
to be able to react to swipe gestures. Layouts such as LazyColumn are
automatically vertically scrollable, but others such as Column or
LazyRow are not. In those instances, you can provide a
Modifier.verticalScroll modifier…
It's from accompanist documentation about the migration of the API but it still applies to this current one in compose framework.
The way I understand it is a scroll event should be present for the PullRefresh to get activated manually (i.e a layout/container with a vertical scroll modifier or a LazyColumn), something that will consume a drag/swipe event in the screen.
Here's the short working sample. All of these are copy-and-paste-able.
Activity:
class PullRefreshActivity: ComponentActivity() {
private val viewModel: MyViewModel by viewModels()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
MyAppTheme {
Surface(
modifier = Modifier.fillMaxSize(),
color = MaterialTheme.colors.background
) {
Scaffold(
modifier = Modifier.fillMaxSize(),
topBar = { TopAppBarSample() }
) {
MyScreen(
modifier = Modifier.padding(it),
viewModel = viewModel
)
}
}
}
}
}
}
Some data classes:
data class MessageItems(
val message: String = "",
val author: String = ""
)
data class DashboardBanner(
val bannerMessage: String = "",
val content: String = ""
)
ViewModel:
class MyViewModel: ViewModel() {
var isLoading by mutableStateOf(false)
private val _messageState = MutableStateFlow(mutableStateListOf<MessageItems>())
val messageState = _messageState.asStateFlow()
private val _dashboardState = MutableStateFlow(DashboardBanner())
val dashboardState = _dashboardState.asStateFlow()
fun fetchMessages() {
viewModelScope.launch {
isLoading = true
delay(2000L)
_messageState.update {
it.add(
MessageItems(
message = "Hello First Message",
author = "Author 1"
),
)
it.add(
MessageItems(
message = "Hello Second Message",
author = "Author 2"
)
)
it
}
isLoading = false
}
}
fun fetchDashboard() {
viewModelScope.launch {
isLoading = true
delay(2000L)
_dashboardState.update {
it.copy(
bannerMessage = "Hello World!!",
content = "Welcome to Pull Refresh Content!"
)
}
isLoading = false
}
}
}
Tab Screen Composables:
#Composable
fun MessageTab(
myViewModel : MyViewModel
) {
val messages by myViewModel.messageState.collectAsState()
LazyColumn(
modifier = Modifier.fillMaxSize()
) {
items(messages) { item ->
Column(
modifier = Modifier
.fillMaxWidth()
.border(BorderStroke(Dp.Hairline, Color.DarkGray)),
horizontalAlignment = Alignment.CenterHorizontally
) {
Text(text = item.message)
Text(text = item.author)
}
}
}
}
#Composable
fun DashboardTab(
myViewModel: MyViewModel
) {
val banner by myViewModel.dashboardState.collectAsState()
Box(
modifier = Modifier
.fillMaxSize()
.verticalScroll(rememberScrollState()),
contentAlignment = Alignment.Center
) {
Column {
Text(
text = banner.bannerMessage,
fontSize = 52.sp
)
Text(
text = banner.content,
fontSize = 16.sp
)
}
}
}
Finally, the composable that contains the PullRefresh and the Pager/Tab components, and all of them are direct children of a ConstraintLayout. So to achieve a PullRefresh behind the Tabs but still on top of the HorizontalPager, first I had to put the HorizontalPager as the first child, the PullRefresh as the second and the Tabs as the last one, constraining them accordingly to preserve the visual arrangement of a Tab Pager.
#OptIn(ExperimentalMaterialApi::class, ExperimentalPagerApi::class)
#Composable
fun MyScreen(
modifier : Modifier = Modifier,
viewModel: MyViewModel
) {
val refreshing = viewModel.isLoading
val pagerState = rememberPagerState()
val pullRefreshState = rememberPullRefreshState(
refreshing = refreshing,
onRefresh = {
when (pagerState.currentPage) {
0 -> {
viewModel.fetchMessages()
}
1 -> {
viewModel.fetchDashboard()
}
}
},
refreshingOffset = 100.dp // just an arbitrary offset where the refresh will animate
)
ConstraintLayout(
modifier = modifier
.fillMaxSize()
.pullRefresh(pullRefreshState)
) {
val (pager, pullRefresh, tabs) = createRefs()
HorizontalPager(
count = 2,
state = pagerState,
modifier = Modifier.constrainAs(pager) {
top.linkTo(tabs.bottom)
start.linkTo(parent.start)
end.linkTo(parent.end)
bottom.linkTo(parent.bottom)
height = Dimension.fillToConstraints
}
) { page ->
when (page) {
0 -> {
MessageTab(
myViewModel = viewModel
)
}
1 -> {
DashboardTab(
myViewModel = viewModel
)
}
}
}
PullRefreshIndicator(
modifier = Modifier.constrainAs(pullRefresh) {
top.linkTo(parent.top)
start.linkTo(parent.start)
end.linkTo(parent.end)
},
refreshing = refreshing,
state = pullRefreshState,
)
ScrollableTabRow(
modifier = Modifier.constrainAs(tabs) {
top.linkTo(parent.top)
start.linkTo(parent.start)
end.linkTo(parent.end)
},
selectedTabIndex = pagerState.currentPage,
indicator = { tabPositions ->
TabRowDefaults.Indicator(
modifier = Modifier.tabIndicatorOffset(
currentTabPosition = tabPositions[pagerState.currentPage],
)
)
},
) {
Tab(
selected = pagerState.currentPage == 0,
onClick = {},
text = {
Text(
text = "Messages"
)
}
)
Tab(
selected = pagerState.currentPage == 1,
onClick = {},
text = {
Text(
text = "Dashboard"
)
}
)
}
}
}
output:
<Surface>
<Scaffold>
<ConstraintLayout>
// top to ScrollableTabRow's bottom
// start, end, bottom to parent's start, end and bottom
// 0.dp (view), fillToConstraints (compose)
<HorizontalPager>
<PagerScreens/>
</HorizontalPager>
// top, start, end of parent
<PullRefreshIndicator/>
// top, start and end of parent
<ScrollableTabRow>
<Tab/> // Set for the first "Messages" tab
<Tab/> // Set for the second "Dashboard" tab
</ScrollableTabRow>
</ConstraintLayout>
<Scaffold>
</Surface>
I think there's nothing wrong with the PullRefresh api and the Compose/Accompanist Tab/Pager api being used together, it seems like the PullRefresh is just respecting the placement structure of the layout/container it is put into.
Consider this code, no tabs, no pager, just a simple set-up of widgets that is identical to your set-up
Column(
modifier = Modifier.padding(it)
) {
Box(
modifier = Modifier
.fillMaxWidth()
.height(80.dp)
.background(Color.Blue)
)
val pullRefreshState = rememberPullRefreshState(
refreshing = false,
onRefresh = { viewModel.fetchMessages() }
)
Box(
modifier = Modifier.pullRefresh(pullRefreshState)
) {
PullRefreshIndicator(
modifier = Modifier.align(Alignment.TopCenter),
refreshing = false,
state = pullRefreshState,
)
}
}
What it looks like.
The PullRefresh is placed inside a component(Box) that is placed below another component in a Column vertical placement, and since it's below another widget, its initial position will not be hidden like the image sample.
With your set-up, since I noticed that the ViewModel is being shared by the tabs and also the reason why I was confirming if you are decided with your architecture is because the only fix I can think of is moving the PullRefresh up in the sequence of the composable widgets.
First changes I made is in your ChatExampleScreen composable, which ended up like this, all PullRefresh components are removed.
#Composable
fun ChatExampleScreen(
chatexampleViewModel: ChatExampleViewModel,
modifier: Modifier = Modifier
) {
val chatexampleViewModelState by chatexampleViewModel.state.observeAsState()
Box(
modifier = modifier
.fillMaxSize()
) {
when (val result = chatexampleViewModelState) {
is ChatExampleViewModel.State.SuccessfullyLoadedMessages -> {
ChatExampleScreenSuccessfullyLoadedMessages(
chatexampleMessages = result.list,
modifier = modifier,
)
}
is ChatExampleViewModel.State.NoMessagesFetched -> {
ChatExampleScreenEmptyState(
modifier = modifier
)
}
is ChatExampleViewModel.State.NoInternetConnectivity -> {
NoInternetConnectivityScreen(
modifier = modifier
)
}
else -> {
// Agus - Do nothing???
Box(modifier = modifier.fillMaxSize())
}
}
}
}
and in your Activity I moved all the setContent{…} scope into another function named ChatTabsContent and placed everything inside it including the PullRefresh components.
#OptIn(ExperimentalMaterialApi::class)
#Composable
fun ChatTabsContent(
modifier : Modifier = Modifier,
viewModel : ChatExampleViewModel
) {
val chatexampleViewModelIsLoadingState by viewModel.isLoading.observeAsState()
val pullRefreshState = rememberPullRefreshState(
refreshing = chatexampleViewModelIsLoadingState == true,
onRefresh = { viewModel.fetchMessages() }
)
Box(
modifier = modifier
.pullRefresh(pullRefreshState)
) {
Column(
Modifier
.fillMaxSize()
) {
val pagerState = rememberPagerState()
ScrollableTabRow(
selectedTabIndex = pagerState.currentPage,
indicator = { tabPositions ->
TabRowDefaults.Indicator(
modifier = Modifier.tabIndicatorOffset(
currentTabPosition = tabPositions[pagerState.currentPage],
)
)
}
) {
Tab(
selected = pagerState.currentPage == 0,
onClick = { },
text = {
Text(
text = "Messages"
)
}
)
Tab(
selected = pagerState.currentPage == 1,
onClick = { },
text = {
Text(
text = "Dashboard"
)
}
)
}
HorizontalPager(
count = 2,
state = pagerState,
modifier = Modifier.fillMaxWidth(),
) { page ->
when (page) {
0 -> {
ChatExampleScreen(
chatexampleViewModel = viewModel,
modifier = Modifier.fillMaxSize()
)
}
1 -> {
ChatExampleScreen(
chatexampleViewModel = viewModel,
modifier = Modifier.fillMaxWidth()
)
}
}
}
}
PullRefreshIndicator(
modifier = Modifier.align(Alignment.TopCenter),
refreshing = chatexampleViewModelIsLoadingState == true,
state = pullRefreshState,
)
}
}
which ended up like this
setContent {
TheOneAppTheme {
// A surface container using the 'background' color from the theme
Surface(
modifier = Modifier.fillMaxSize(),
color = MaterialTheme.colors.background
) {
Scaffold(
modifier = Modifier.fillMaxSize(),
topBar = { TopAppBarSample() }
) {
ChatTabsContent(
modifier = Modifier.padding(it),
viewModel = viewModel
)
}
}
}
}
Result:
Structural changes.
<Surface>
<Scaffold> // Set with a topBar
<Box>
<Column>
<ScrollableTabRow>
<Tab/> // Set for the first "Messages" tab
<Tab/> // Set for the second "Dashboard" tab
</ScrollableTabRow>
<HorizontalPager>
<Box/>
</HorizontalPager>
</Column>
// pull refresh is now at the most "z" index of the
// box, overlapping the content (tabs/pager)
<PullRefreshIndicator/>
</Box>
<Scaffold>
</Surface>
I haven't explored this API yet, but it looks like it should be used directly in a z-oriented layout/container parent such as Box as the last child.
I just want to share more details about the issue here and what the solution is. I appreciate a lot the solutions shared above and these were definitely key to figuring the problem out.
The bare-minimum solution here is to replace the Box with a ConstraintLayout in the ChatScreenExample composable:
Why? Because as #z.y shared above the PullRefreshIndicator needs to be contained on a "vertically scrollable" composable, and while the Box composable can be set with the vericalScroll() modifier we need to make sure we constraint the height of the content, that's why we had to change to a ConstraintLayout.
Feel free to correct me if I'm missing something.
There is yet another solution to this problem, which is using a .clipToBounds() modifier over the tab content container.

Jetpack Compose LazyColumn inside Scrollabe Column

here's my situation: I have to show in my app a detail of a record I receive from API. Inside this view, I may or may not need to show some data coming from another viewmodel, based on a field.
Here my code:
#OptIn(ExperimentalMaterial3Api::class)
#Composable
fun ViewDetail(viewModel: MainViewModel, alias: String?, otherViewModel: OtherViewModel) {
viewModel.get(alias)
Scaffold {
val isLoading by viewModel.isLoading.collectAsState()
val details by viewModel.details.collectAsState()
when {
isLoading -> LoadingUi()
else -> Details(details, otherViewModel)
}
}
}
#OptIn(ExperimentalMaterial3Api::class)
#Composable
private fun Details(details: Foo?, otherViewModel: OtherViewModel) {
details?.let { sh ->
val scrollState = rememberScrollState()
Column(
modifier = Modifier
.fillMaxSize()
.verticalScroll(scrollState),
) {
Text(sh.title, fontSize = 24.sp, lineHeight = 30.sp)
Text(text = sh.description)
if (sh.other.isNotEmpty()) {
otherViewModel.load(sh.other)
val others by otherViewModel.list.collectAsState()
Others(others)
}
}
}
}
#OptIn(ExperimentalMaterial3Api::class)
#Composable
private fun Others(others: Flow<PagingData<Other>>) {
val items: LazyPagingItems<Other> = others.collectAsLazyPagingItems()
LazyColumn(
modifier = Modifier
.fillMaxWidth()
.wrapContentHeight(),
contentPadding = PaddingValues(16.dp),
) {
items(items = items) { item ->
if (item != null) {
Text(text = item.title, fontSize = 24.sp)
Spacer(modifier = Modifier.height(4.dp))
Text(text = item.description)
}
}
if (items.itemCount == 0) {
item { EmptyContent() }
}
}
}
All the description here may be very long, both on the main Details body or in the Others (when present), so here's why the scroll behaviour requested.
Problem: I get this error:
Vertically scrollable component was measured with an infinity maximum height constraints, which is disallowed. One of the common reasons is nesting layouts like LazyColumn and Column(Modifier.verticalScroll()).
I hoped that .wrapContentHeight() inside LazyColumn would do the trick, but to no avail.
Is this the right way to do it?
Context: all packages are updated to the latest versions available on maven
The main idea here is to merge your Column with LazyColumn.
As your code is not runnable, I'm giving more a pseudo code, which should theoretically work.
Also calling otherViewModel.load(sh.other) directly from Composable builder is a mistake. According to thinking in compose, to get best performance your view should be side effects free. To solve this issue Compose have special side effect functions. Right now your code is gonna be called on each recomposition.
if (sh.other.isNotEmpty()) {
LaunchedEffect(Unit) {
otherViewModel.load(sh.other)
}
}
val others by otherViewModel.list.collectAsState()
LazyColumn(
modifier = Modifier
.fillMaxSize()
.wrapContentHeight(),
contentPadding = PaddingValues(16.dp),
) {
item {
Text(sh.title, fontSize = 24.sp, lineHeight = 30.sp)
Text(text = sh.description)
}
items(items = items) { item ->
if (item != null) {
Text(text = item.title, fontSize = 24.sp)
Spacer(modifier = Modifier.height(4.dp))
Text(text = item.description)
}
}
if (items.itemCount == 0) {
item { EmptyContent() }
}
}
You can use a system like the following
#Composable
fun Test() {
Box(Modifier.systemBarsPadding()) {
Details()
}
}
#Composable
fun Details() {
LazyColumn(Modifier.fillMaxSize()) {
item {
Box(Modifier.background(Color.Cyan).padding(16.dp)) {
Text(text = "Hello World!")
}
}
item {
Box(Modifier.background(Color.Yellow).padding(16.dp)) {
Text(text = "Another data")
}
}
item {
Others()
}
}
}
#Composable
fun Others() {
val values = MutableList(50) { it }
values.forEach {
Box(
Modifier
.fillMaxWidth()
.padding(16.dp)
) {
Text(text = "Value = $it")
}
}
}
The result with scroll is:

Jetpack Compose: How to put a LazyVerticalGrid inside a scrollable Column?

When trying to put a LazyVerticalGrid inside a scrollable Column I get the following error:
java.lang.IllegalStateException: Nesting scrollable in the same
direction layouts like LazyColumn and
Column(Modifier.verticalScroll()) is not allowed. If you want to add a
header before the list of items please take a look on LazyColumn
component which has a DSL api which allows to first add a header via
item() function and then the list of items via items().
I am not making a traditional list, I just have alot of elements that are too big to fit on the screen. Therefore I want the column to scroll so I can see all the elements. Here is my code:
#ExperimentalFoundationApi
#Composable
fun ProfileComposable(id: String?) {
val viewModel: ProfileViewModel = viewModel()
if (id != null) {
viewModel.getProfile(id)
val profile = viewModel.profile.value
val scrollState = rememberScrollState()
if (profile != null) {
Column(modifier = Modifier
.fillMaxWidth()
.fillMaxHeight()
.verticalScroll(scrollState)) {
Row() {
ProfilePic(profile.getImgUrl(), profile.name)
Column(Modifier.padding(16.dp)) {
ProfileName(profile.name)
Stats(profile.stats) // <--------------- the offending composable
}
}
Sprites(sprites = profile.sprites)
TextStat(profile.id.toString(), "Pokemon Number")
TextStat(profile.species.name, "Species")
TextStat(profile.types.joinToString { it.type.name }, "Types")
TextStat(profile.weight.toString(), "Weight")
TextStat(profile.forms.joinToString { it.name }, "Forms")
}
} else {
Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
CircularProgressIndicator()
}
}
} else {
Text("Error")
}
}
The Stats() composable contains the LazyVerticalGrid which causes the error:
#ExperimentalFoundationApi
#Composable
fun Stats(stats: List<Stat>) {
LazyVerticalGrid(cells = GridCells.Fixed(2)) {
itemsIndexed(stats) { index, item ->
StatBox(stat = item)
}
}
}
I do not want the grid to scroll, I just want to display a grid within a scrollable column.
I had a similar use-case, the goal was to design a profile screen that has a bunch of information and statistics on top, and then comes to the posts as a Grid in the bottom of the screen.
I ended up using the LazyVerticalGrid for the whole list and setting full span for the items that need to fill the entire screen:
LazyVerticalGrid(cells = GridCells.Fixed(3)) {
item(span = { GridItemSpan(3) }) { TopInfo() }
item(span = { GridItemSpan(3) }) { SomeOtherInfo() }
item(span = { GridItemSpan(3) }) { BottomInfo() }
items(gridItems) { GridItemView(it) }
}
I just ran into this problem myself. As #gaohomway said, your best bet is to use the experimental FlowRow() from Google's Accompanist library.
Here is a working code snippet as an example:
#Composable
fun ProfileScreen2() {
LazyColumn(
modifier = Modifier
.fillMaxSize()
) {
item {
Box(modifier = Modifier.fillMaxWidth().height(200.dp).background(color = Red))
}
item {
Box(modifier = Modifier.fillMaxWidth().height(200.dp).background(color = Gray))
}
item {
FlowRow() {
SampleContent()
}
}
}
}
#Composable
internal fun SampleContent() {
repeat(60) {
Box(
modifier = Modifier
.size(64.dp)
.background(Blue)
.border(width = 1.dp, color = DarkGray),
contentAlignment = Alignment.Center,
) {
Text(it.toString())
}
}
}
Displays this scrollable page (don't mind the nav bar at the bottom):
Reason
Nesting scrollable in the same direction layouts like LazyColumn and Column(Modifier.verticalScroll()) is not allowed.
Can't find LazyVerticalGrid forbidden scrolling temporarily
Alternatives
Alternative library from Android official Jetpack Compose Flow Layouts
FlowRow {
// row contents
}
FlowColumn {
// column contents
}
try using exact height for LazyVerticalGrid, it worked for me :
#ExperimentalFoundationApi
#Composable
fun Stats(stats: List<Stat>) {
LazyVerticalGrid(columns = GridCells.Fixed(2),
modifier = Modifier.height(50.dp)) {
itemsIndexed(stats) { index, item ->
StatBox(stat = item)
}
}
}
I ran into this same issue but in my case I just wanted to display 1-10 items with the same Composable component but different parameters, so I ended up creating a custom grid where you can pass:
List of composables
number of desired items per row
#Composable
fun VerticalGrid(composableList: List<#Composable () -> Unit>, itemsPerRow: Int) {
val components = composableList.toMutableList()
Column(Modifier.fillMaxWidth()) {
while (components.isNotEmpty()) {
val rowComponents: List<#Composable () -> Unit> = components.take(itemsPerRow)
val listOfSpacers: List<#Composable () -> Unit> = listOfSpacers(itemsPerRow - rowComponents.size)
RowWithItems(items = rowComponents.plus(listOfSpacers))
components.removeAll(rowComponents)
}
}
}
private fun listOfSpacers(number: Int): List<#Composable () -> Unit> {
val mutableList = emptyList<#Composable () -> Unit>().toMutableList()
repeat(number) {
mutableList.add { Spacer(Modifier) }
}
return mutableList.toList()
}
#Composable
private fun RowWithItems(items: List<#Composable () -> Unit>) {
Row(Modifier.fillMaxWidth()) {
items.forEach { item ->
Box(Modifier.weight(1f)) {
item()
}
}
}
}
Example on how to call:
VerticalGrid(
composableList = listOf(
{ ProfileDataField(value = profileInfo.country.name) },
{ ProfileDataField(value = profileInfo.dateOfBirth) },
{ ProfileDataField(value = profileInfo.gender) }
),
itemsPerRow = 2
)
Might not be the best for performance and it's definitely not lazy but currently there is no non-lazy Grid for this purpose.

Multiple BottomSheets for one ModalBottomSheetLayout in Jetpack Compose

I want to implement a screen which can show two different bottom sheets.
Since ModalBottomSheetLayout only has a slot for one sheet I decided to change the sheetContent of the ModalBottomSheetLayout dynamically using a selected state when I want to show either of the two sheets (full code).
val sheetState = rememberModalBottomSheetState(initialValue = ModalBottomSheetValue.Hidden)
val (selected, setSelected) = remember(calculation = { mutableStateOf(0) })
ModalBottomSheetLayout(sheetState = sheetState, sheetContent = {
when (selected) {
0 -> Layout1()
1 -> Layout2()
}
}) {
Content(sheetState = sheetState, setSelected = setSelected)
}
This works fine for very similar sheets, but as soon as you add more complexity to either of the two sheet layouts the sheet will not show when the button is pressed for the first time, it will only show after the button is pressed twice as you can see here:
Here you can find a reproducible example
I had a similar usecase, where I needed to show 2-3 stacked bottomsheets.
I ended up copying large part of Compose BottomSheet and added the desired behavior:
enum class BottomSheetValue { SHOWING, HIDDEN }
#Composable
fun BottomSheet(
parentHeight: Int,
topOffset: Dp = 0.dp,
fillMaxHeight: Boolean = false,
sheetState: SwipeableState<BottomSheetValue>,
shape: Shape = bottomSheetShape,
backgroundColor: Color = MaterialTheme.colors.background,
contentColor: Color = contentColorFor(backgroundColor),
elevation: Dp = 0.dp,
content: #Composable () -> Unit
) {
val topOffsetPx = with(LocalDensity.current) { topOffset.roundToPx() }
var bottomSheetHeight by remember { mutableStateOf(parentHeight.toFloat())}
val scrollConnection = sheetState.PreUpPostDownNestedScrollConnection
BottomSheetLayout(
maxHeight = parentHeight - topOffsetPx,
fillMaxHeight = fillMaxHeight
) {
val swipeable = Modifier.swipeable(
state = sheetState,
anchors = mapOf(
parentHeight.toFloat() to BottomSheetValue.HIDDEN,
parentHeight - bottomSheetHeight to BottomSheetValue.SHOWING
),
orientation = Orientation.Vertical,
resistance = null
)
Surface(
shape = shape,
color = backgroundColor,
contentColor = contentColor,
elevation = elevation,
modifier = Modifier
.nestedScroll(scrollConnection)
.offset { IntOffset(0, sheetState.offset.value.roundToInt()) }
.then(swipeable)
.onGloballyPositioned {
bottomSheetHeight = it.size.height.toFloat()
},
) {
content()
}
}
}
#Composable
private fun BottomSheetLayout(
maxHeight: Int,
fillMaxHeight: Boolean,
content: #Composable () -> Unit
) {
Layout(content = content) { measurables, constraints ->
val sheetConstraints =
if (fillMaxHeight) {
constraints.copy(minHeight = maxHeight, maxHeight = maxHeight)
} else {
constraints.copy(maxHeight = maxHeight)
}
val placeable = measurables.first().measure(sheetConstraints)
layout(placeable.width, placeable.height) {
placeable.placeRelative(0, 0)
}
}
}
TopOffset e.g. allows to place the bottomSheet below the AppBar:
BoxWithConstraints {
BottomSheet(
parentHeight = constraints.maxHeight,
topOffset = with(LocalDensity.current) {56.toDp()}
fillMaxHeight = true,
sheetState = yourSheetState,
) {
content()
}
}
I wanted to implement the same thing and because of the big soln, I wrote a post on dev.to that solves this problem, Here is the link
I implemented it like this. It looks pretty simple, but I still could not figure out how to pass the argument to "mutableStateOf ()" directly, I had to create a variable "content"
fun Screen() {
val bottomSheetState = rememberModalBottomSheetState(ModalBottomSheetValue.Hidden)
val scope = rememberCoroutineScope()
val content: #Composable (() -> Unit) = { Text("NULL") }
var customSheetContent by remember { mutableStateOf(content) }
ModalBottomSheetLayout(
sheetState = bottomSheetState,
sheetContent = {
customSheetContent()
}
) {
Column {
Button(
onClick = {
customSheetContent = { SomeComposable1() }
scope.launch { bottomSheetState.show() }
}) {
Text("First Button")
}
Button(
onClick = {
customSheetContent = { SomeComposable2() }
scope.launch { bottomSheetState.show() }
}) {
Text("Second Button")
}
}
}
I just tried your code. I am not sure but looks like when you click first time, since selected state changes, Content function tries to recompose itself and it somehow blocks sheetState. Because i can see that when i click first time, bottom sheet shows up a little and disappears immediately. But second time i click same button, since selected state doesnt change, sheetState works properly.

Categories

Resources