In LazyColumn when we use LazyListScope.items with Surface. Inside multiple items there is extra padding on TOP and BOTTOM. I want to remove this padding. I am using Surface component of Material 3. BOM version is compose_bom = "2022.11.00".
Please don't suggest any alpha or beta version fix. If Material 3 stable api don't have solution, then please suggest normal Surface Material.
PreviewCreateListView
#Preview(showBackground = true)
#Composable
fun PreviewCreateListView() {
CreateListView()
}
CreateListView
#OptIn(ExperimentalMaterial3Api::class)
#Composable
fun CreateListView() {
val itemList = listOf(1, 2, 3)
LazyColumn(
contentPadding = PaddingValues(16.dp),
) {
items(itemList) { item ->
Surface(
onClick = { },
color = Color.Blue
) {
Text(
modifier = Modifier.fillMaxWidth(),
text = "$item",
)
}
}
}
}
Output
The M3 Surface with the onClick parameter has a minimum touch target size (48.dp) for accessibility. It will include extra space outside the component to ensure that they are accessible.
You can override this behaviour applying false to the LocalMinimumInteractiveComponentEnforcement. If it is set to false there will be no extra space.
Something like:
CompositionLocalProvider(
LocalMinimumInteractiveComponentEnforcement provides false) {
Surface(
onClick = { },
color = Color.Blue
) {
Text(
modifier = Modifier.fillMaxWidth(),
text = "$item",
)
}
}
Note: LocalMinimumInteractiveComponentEnforcement requires at least
M2 1.4.0-alpha04 and M3 1.1.0-alpha04. Before you can use LocalMinimumTouchTargetEnforcement in the same way.
The Surface variant that you use, with a onClick parameter, enforces a minimum height for accessibility purposes, see this at line 221
If you want to remove the space, use the variant without the onClick argument and use a Modifier.clickable instead
#Composable
fun CreateListView() {
val itemList = listOf(1, 2, 3)
LazyColumn(
contentPadding = PaddingValues(16.dp),
) {
items(itemList) { item ->
Surface(
modifier = Modifier.clickable { },
color = Color.Blue
) {
Text(
modifier = Modifier.fillMaxWidth(),
text = "$item",
)
}
}
}
}
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.
I have a Text and I want to draw a circle that should have a color that exists inside my resource file.
Text(
modifier = Modifier.align(Alignment.TopEnd).drawBehind {
drawCircle(
color = colorResource(R.color.primary),
radius = 96.00f
)
},
text = "X"
)
But I get:
#Composable invocations can only happen from the context of a #Composable function
If I use color = Color.Red, it works fine. So I don't want to use any of those colors, I want to use mine. So I thought to make a conversion, but I cannot find any solution. How can I convert that?
You need to call Composable functions from a scope that has #Composable annotation.
Box() {
val color = colorResource(R.color.black)
Text(
modifier = Modifier.align(Alignment.TopEnd).drawBehind {
drawCircle(
color = color,
radius = 96.00f
)
},
text = "X"
)
}
colorResource is a #Composable function
#Composable
#ReadOnlyComposable
fun colorResource(#ColorRes id: Int): Color {
val context = LocalContext.current
return if (Build.VERSION.SDK_INT >= 23) {
ColorResourceHelper.getColor(context, id)
} else {
#Suppress("DEPRECATION")
Color(context.resources.getColor(id))
}
}
but lambda of Modifier.drawBehind isn't
fun Modifier.drawBehind(
onDraw: DrawScope.() -> Unit
) = this.then(
DrawBackgroundModifier(
onDraw = onDraw,
inspectorInfo = debugInspectorInfo {
name = "drawBehind"
properties["onDraw"] = onDraw
}
)
)
You can check this answer for difference between function, lambdas or params with #Composable annotation or the ones without
I'm trying to display a linear gradient over a background image so it's easier to read the text on the image. But do to the lack of documentation it's not easy to do. I want to accomplish something like this.
Here is my component:
#Composable
override fun MakeComposable(screen: ScreenID?, onEvent: (ScreenEvent) -> Unit) {
if (screen == null) return
val gradient = Brush.linearGradient(
colors = listOf(Color.Transparent, Color.Black),
start = Offset.Zero,
end = Offset.Infinite,
tileMode = TileMode.Clamp
)
ComposeTestTheme {
Box(modifier = Modifier.background(color = MaterialTheme.colors.surface))
{
screen.backgroundImage?.let { ui.Image(ImageData(url = it), onEvent = onEvent) }
LazyColumn(horizontalAlignment = Alignment.CenterHorizontally, modifier = Modifier.fillMaxSize()) {
this.items(screen.modules) { module ->
ModuleComposable(ui, module, onEvent)
}
}
}
Box(modifier = Modifier.fillMaxSize().background(gradient))
}
}
You can create a composable with a Box to pill each composables on top of each other. It would look like this (pseudo code):
#Composable
fun ShadowedImage(modifier = Modifier) {
Box(modifier) {
Image(modifier = Modifier.fillMaxSize())
Surface(modifier = Modifier.fillMaxSize().background(brush = gradient))
Text(text = "Your text")
}
}
Building a simple keyboard is fairly simple and straightforward in Jetpack Compose.
I built a really simple KeyRow by using this:
Key.kt
#Composable
fun Key(modifier: Modifier = Modifier, label: String, onClick: () -> Unit) {
val shape = RoundedCornerShape(4.dp)
//TODO: make clickable outside but don't show ripple
Box(modifier = modifier
.padding(2.dp)
.clip(shape)
.clickable(onClick = onClick)
.background(Color.White)
.padding(vertical = 12.dp, horizontal = 4.dp), contentAlignment = Alignment.Center) {
Text(text = label, fontSize = 20.sp)
}
}
KeyRow.kt
#Composable
fun KeyRow(keys: List<String>) {
Row(modifier = Modifier.fillMaxWidth().background(color = grey200)) {
keys.forEach {
Key(modifier = Modifier.weight(1f), label = it, onClick = { })
}
}
}
That's what it looks like:
I want to achieve this animation:
However, I'm currently stuck with this
![4]
Hierachy
-Keyboard
--KeyRow
---KeyLayout
----Key
----KeyPressedOverlay (only visible when pressed)
My main problem is that I don't know how to show the KeyPressedOverlay Composale (which is larger than the Key Composable) without making the parent Layout larger. As a result, I need to overflow the parent layout in some way.
Not sure if it's the best way (probably not), but I found a solution using ConstraintLayout...
val keys = listOf("A", "B", "C", "D")
ConstraintLayout(
modifier = Modifier.graphicsLayer(clip = false)
) {
val refs = keys.map { createRef() }
refs.forEachIndexed { index, ref ->
val modifier = when (index) {
0 -> Modifier.constrainAs(ref) {
start.linkTo(parent.start)
}
refs.lastIndex -> Modifier.constrainAs(ref) {
start.linkTo(refs[index - 1].end)
end.linkTo(parent.end)
}
else -> Modifier.constrainAs(ref) {
start.linkTo(refs[index - 1].end)
end.linkTo(refs[index + 1].start)
}
}
val modifierPressed = Modifier.constrainAs(createRef()) {
start.linkTo(ref.start)
end.linkTo(ref.end)
bottom.linkTo(ref.bottom)
}
KeyboardKey(
keyboardKey = keys[index],
modifier = modifier,
modifierPressed = modifierPressed,
pressed = { s -> /* Do something with the key */}
)
}
}
One important detail here is graphicLayer(clip = false) (which is similar to the clipChildren in View Toolkit). Then, I'm creating a modifier to each key and to the pressed key. Noticed that the modifierPressed is aligned to the center/bottom of the other modifier.
Finally the KeyboardKey is described below.
#Composable
fun KeyboardKey(
keyboardKey: String,
modifier: Modifier,
modifierPressed: Modifier,
pressed: (String) -> Unit
) {
var isKeyPressed by remember { mutableStateOf(false) }
Text(keyboardKey, Modifier
.then(modifier)
.pointerInput(Unit) {
detectTapGestures(onPress = {
isKeyPressed = true
val success = tryAwaitRelease()
if (success) {
isKeyPressed = false
pressed(keyboardKey)
} else {
isKeyPressed = false
}
})
}
.background(Color.White)
.padding(
start = 12.dp,
end = 12.dp,
top = 16.dp,
bottom = 16.dp
),
color = Color.Black
)
if (isKeyPressed) {
Text(
keyboardKey, Modifier
.then(modifierPressed)
.background(Color.White)
.padding(
start = 16.dp,
end = 16.dp,
top = 16.dp,
bottom = 48.dp
),
color = Color.Black
)
}
}
This is the result I got:
Edit:
Adding some more logic, I was able to get this...
I hope it helps this time ;)
Here's the gist just in case...
https://gist.github.com/nglauber/4cb1573efba9024c008ea71f3320b4d8
I guess you're looking for the pressIndicatorGestureFilter modifier...
I tried this and worked for me...
var pressed by remember { mutableStateOf(false) }
val padding = if (pressed) 32.dp else 16.dp
Text("A", Modifier
.pressIndicatorGestureFilter(
onStart = {
pressed = true
},
onStop = {
pressed = false
},
onCancel = {
pressed = false
}
)
.background(Color.White)
.padding(start = 16.dp, end = 16.dp, top = padding, bottom = padding)
)