Jetpack Compose TopAppBar with search bar embedded

Question

I'm trying to implement something that I feel should be easy but I'm having a hard time.

I have a screen with a scaffold, topbar, and lazycolumn as content:

I'm using a M3 TopAppBar with a enterAlwaysScrollBehavior so it disappears/appears when the content is scrolled.

What I want to do is implement the search button. How can I make that once the search icon is tapped, the "Cards" title turns into a textfield to input a search query?

I've done this easily using a Row and Crossfade instead of TopAppBar, but then I lose the scrollBehavior feature.

Any ideas?

Thanks, and happy new year!

dmortal · Accepted Answer · 2025-01-15 09:20:18Z

Did the following:

@OptIn(ExperimentalMaterial3Api::class) @Composable internal fun SearchAppBar() { val scrollBehavior = TopAppBarDefaults.enterAlwaysScrollBehavior() Scaffold( modifier = Modifier.nestedScroll(scrollBehavior.nestedScrollConnection), topBar = { var isSearch by remember { mutableStateOf(false) } var value by remember { mutableStateOf("") } Crossfade( modifier = Modifier.animateContentSize(), targetState = isSearch, label = "Search" ) { target -> if (!target) { TopAppBar( title = { Text("Cards") }, actions = { IconButton(Icons.Filled.Search) { isSearch = !isSearch } }, scrollBehavior = scrollBehavior, ) } else { TextField( modifier = Modifier .fillMaxWidth() .windowInsetsPadding(TopAppBarDefaults.windowInsets) .layout { measurable, constraints -> val placeable = measurable.measure(constraints) val height = placeable.height * (1 - scrollBehavior.state.collapsedFraction) layout(placeable.width, height.roundToInt()) { placeable.place(0, 0) } }, value = value, placeholder = { Text("Enter card name") }, onValueChange = { value = it }, leadingIcon = { IconButton(Icons.AutoMirrored.Filled.ArrowBack) { isSearch = !isSearch } }, trailingIcon = if (value.isNotBlank()) { { IconButton(Icons.Filled.Close) { value = "" } } } else { null } ) } } }, ) { paddingValues -> LazyColumn( Modifier .fillMaxSize() .padding(paddingValues) ) { items(200) { index -> Text(modifier = Modifier.fillMaxWidth(), text = "Title $index") } } } } @Composable fun IconButton(imageVector: ImageVector, onClick: () -> Unit) { IconButton(onClick = onClick) { Icon( imageVector = imageVector, contentDescription = null ) } }

it works, thanks! Wondering why there isn't a more intuitive way to achieve this. Seems a pretty common topbar usage for it to be this “tricky” @dmortal
@FerranLP Unfortunately I don't work for Google, so I can't give you an exact answer. I think they make some common component, where you can add any action, not only search, but also menu for example (with Navigation drawer opening).
This doesn't work for me :( I get empty topbar when I use this code. It seems that topBar parameter is expecting a @Composable () -> Unit parameter and then executes what is inside, so, as soon as I add the Crossfade {} wrapper, it stops showing any appbar. Any suggestion on how to fix this?
OK. I found the issue...Apparently, my CustomizedAppBar was already returning a () -> Unit function instead of returning just Unit, so I changed the returning type of the CustomizedAppBar and now I could do it like this. Thank you very much!

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