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 AppBarNavGraph and RootNavGraph.
I'd like to know two methods, Full Screen Dialog and also Navigating to a new Screen.
What I am trying to is..
Column(
modifier = Modifier
.width(97.dp)
.clickable {
Dialog(onDismissResult = { /*TODO*/ }) {
}
}
,
horizontalAlignment = Alignment.CenterHorizontally
But in clickable, composable function is not callable.
So, What I tried is using this,
val isClicked = remember { mutableStateOf(false) }
Column(
modifier = Modifier
.width(97.dp)
.clickable {
isClicked.value = !isClicked.value
},
horizontalAlignment = Alignment.CenterHorizontally
)
if(isClicked.value){
// show full screen dialog or navigate to some screen.
}
Here are two problems.
I tried with Dialog function.
Dialog(
onDismissResult: () -> Unit,
properties: DialogProperties = DialogProperties(),
content: #Composable () -> Unit
)
but, this doesn't show full screen but just next item. (it's in GridLayout and when I click an item, the dialog needs to shows up to add the item.)
For navigation, I tried, varies ways, but I haven't found any clear solutions...
Could you please help me out? or any advices?
This should do the trick for a simple full screen popup
var showPopup by remember { mutableStateOf(false) }
Box(Modifier
.background(Color.Blue)
.fillMaxSize()) {
Button(onClick = { showPopup = true }) {
Text("Show popup")
}
}
if (showPopup) {
Popup(
onDismissRequest = { showPopup = false }
) {
Box(Modifier
.background(Color.Red)
.fillMaxSize()) {
Button(onClick = { showPopup = false },
modifier = Modifier.align(Alignment.Center)) {
Text("Hide popup")
}
}
}
}
Though if you want proper navigation you should probably use this
This question already has answers here:
Why don't Indication work for Button or Icons?
(2 answers)
Closed 6 months ago.
I have seen that we can disable the ripple effect of a view with the clickable(interactionSource, indication) inside for example a row or column but my question is that if we can disable it from a Button or FloatingActionButton
I see that FloatingActionButton has an interactionSource attribute and I have tried this
FloatingActionButton(
modifier = Modifier
.size(40.dp),
onClick = {
buttonState = when (buttonState) {
ButtonState.PRESSED -> ButtonState.UNPRESSED
ButtonState.UNPRESSED -> ButtonState.PRESSED
}
},
interactionSource = remember {
MutableInteractionSource()
})
this is not working to disable the ripple effect.
Then I have tried with the indication modifier like this
FloatingActionButton(
modifier = Modifier
.size(40.dp)
.indication(
interactionSource = remember {
MutableInteractionSource()
},
indication = null
),
onClick = {
buttonState = when (buttonState) {
ButtonState.PRESSED -> ButtonState.UNPRESSED
ButtonState.UNPRESSED -> ButtonState.PRESSED
}
})
also is not working, and then last thing I tried is adding the .clickable(...) in the modifier of the Fab button but I think that is pointless since the button has its own onClick event.
All the cases above yields to this
Is there anyway from any Button to disable its ripple effect without adding a Column or Box with a clickable attribute into its modifier ?
You can change ripple o by providing RippleTheme
private class CustomRippleTheme : RippleTheme {
#Composable
override fun defaultColor(): Color = Color.Unspecified
#Composable
override fun rippleAlpha(): RippleAlpha = RippleAlpha(
draggedAlpha = 0f,
focusedAlpha = 0f,
hoveredAlpha = 0f,
pressedAlpha = 0f,
)
}
Demo
#Composable
private fun RippleDemo() {
Column(
modifier = Modifier
.fillMaxSize()
.padding(50.dp)
) {
Button(onClick = { /*TODO*/ }) {
Text("Button with ripple", fontSize = 20.sp)
}
Spacer(Modifier.height(20.dp))
FloatingActionButton(onClick = { /*TODO*/ }) {
Icon(imageVector = Icons.Filled.Add, contentDescription = null)
}
Spacer(Modifier.height(20.dp))
CompositionLocalProvider(LocalRippleTheme provides CustomRippleTheme()) {
Button(onClick = { /*TODO*/ }) {
Text("Button with No ripple", fontSize = 20.sp)
}
Spacer(Modifier.height(20.dp))
FloatingActionButton(onClick = { /*TODO*/ }) {
Icon(imageVector = Icons.Filled.Add, contentDescription = null)
}
}
}
}
Result
A Button, internally, is just a surface with modifications applied to it to make it clickable. It has a default indication set within the implementation, hence cannot be "turned off" at the calling site.
Just pull up the source code and remove the indication, storing the resultant inside a new Composable.
Just do a quick Ctrl+Left Click on the text "Button" in Studio, and it'll take you there.
How can I change the composables within a row?
For example if I had something like this:
#Composable
fun WordGrid() {
Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceEvenly) {
MyCard("") basically a card with Text
MyCard("")
MyCard("")
}
Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceEvenly) {
MyCard("")
MyCard("")
MyCard("")
}
}
fun MyCard(text: String?) {
Card() {
Text(
text = text?: ""
)
}
}
and two buttons:
Button "A" and Button "B"
each time a button is clicked a card should get the text from the button, and then the next card and then the last.
clicking buttons A B A B would give you:
#Composable
fun WordGrid() {
Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceEvenly) {
MyCard("A") basically a card with Text
MyCard("B")
MyCard("A")
}
Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceEvenly) {
MyCard("B")
MyCard("")
MyCard("")
}
}
How do you go about something like this unidirectionally? With XML you would be able to access the card.id directly from the ViewModel, here they have no id.
Is the only way to check if a button has been pressed and then create a state for that, pass this to the row and run through a for loop?
This seems much more complicated than having a simple id to grab.
In Compose you can't access views by ID. The only way is to manipulate the state which is used to build it.
I suggest you start with this youtube video which explains the basic principles of when you need to use state in compose. You can continue deepening your knowledge with state in Compose documentation.
In your case you can create a mutable state list of strings, build your views based on this list and update it using the buttons by index.
Here's a basic example of what you're trying to do:
val cards = remember { List(6) { "" }.toMutableStateList() }
var editingIndex by remember { mutableStateOf(0) }
Column {
Row {
val editButton = #Composable { text: String ->
Button({
cards[editingIndex] = text
editingIndex += 1
}) {
Text(text)
}
}
editButton("A")
editButton("B")
}
cards.chunked(cards.count() / 2).forEach { rowCards ->
Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceEvenly) {
rowCards.forEach {
MyCard(it)
}
}
}
}
What I found in most of the tutorial on the internet is:
#Composable
fun addButton() {
Button(text = "I'm a Compose Button")
}
But android studio give me an error: type mismatch Required: () -> Unit, Found: String.
I don't know how to fix this.
According to the docs, To create a Button you have to specify the text inside the RowScope:
Button(onClick = {/* To execute when button is clicked */}) {
Text("I'm a Compose Button")
}
The text is then set by Text() function defined in androidx.ui.foundation package.
You can find more about them in the material-ui docs: https://developer.android.com/reference/kotlin/androidx/ui/material/package-summary
This is how you can add Button in Jetpack compose.
Button(onClick = {/*Handle click action */}, modifier = Modifier.padding(16.dp)) {
Text(
text = "Jetpack Compose Button"
)
}
References:
[1] https://developer.android.com/reference/kotlin/androidx/compose/material/package-summary#button
Use blow code
Button(onClick {/* your onClick listener */}){
Text("I'm a Compose Button")
}
I know it does not seems good but u have to do it like this
Button(onClick = {handle Click Action })
{
Text(text = "Your Button Text")
}
those who are new in compose can use button simple button like this
#Composable
fun MyButton() {
Column(
modifier = Modifier.fillMaxWidth().fillMaxHeight(),
verticalArrangement = Arrangement.Center,
horizontalAlignment = Alignment.CenterHorizontally
) {
Button(
onClick = {},
modifier = Modifier.padding(all = Dp(10f)),
enabled = true,
border = BorderStroke(width = 1.dp, brush = SolidColor(Color.Blue))
) {
Text(text = "I am a compose button", color = Color.White)
}
}
}
You are not using the syntax,
you the this code:
Button(onClick = {/*Handle click action */} ){
Text(
text = "Write the button text here"
)
}
if you want to use modifiers then refer to this,
Button(onClick = {/*Handle click action */}, modifier = Modifier.padding(16.dp)) {
Text(
text = "Write the button text here"
)
}