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#compose-android
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# compose-android
h
Håkon Pettersen
10/11/2023, 12:37 PMHi, I need some help understanding why my composable undergoes unnecessary recompositions and how to fix it (details in the thread 🧵). Whenever a value in the state is updated,
ListOfItemInCardGenericDetailSettingRowsGenericDetailRowParent composable:
Copy code
@Composable
fun GenericDetailScreen(
settingRows: List<GenericDetailRow.Settings>,
onRowSelected: (GenericDetailRow) -> Unit,
) {
Scaffold { paddingValues ->
Column(
modifier = Modifier
.padding(paddingValues)
.padding(horizontal = dimensionResource(id = R.dimen.content_padding))
.verticalScroll(rememberScrollState()),
verticalArrangement = Arrangement.spacedBy(dimensionResource(id = R.dimen.half_content_padding)),
) {
GenericDetailSettingRows(
settingRows = settingRows,
onRowSelected = onRowSelected,
)
}
}
} Copy code
@Composable
fun GenericDetailSettingRows(
settingRows: List<GenericDetailRow.Settings>,
onRowSelected: (GenericDetailRow.Settings) -> Unit,
) {
if (settingRows.isNotEmpty()) {
HeaderText(text = { it.getString(R.string.settings) })
ListOfItemInCard(
items = settingRows,
withDividers = true,
) { row ->
when (row) {
GenericDetailRow.Settings.AlarmSettings -> {
RowImageTextArrow(
leadingIconRes = R.drawable.ic_alarm_24dp,
text = { it.getString(R.string.generic_detail_page_smart_alarm_settings) },
onClick = { onRowSelected(row) },
)
}
...
}
}
}
} Copy code
return ComposeView(requireContext()).apply {
setContent {
val state = viewModel.state.collectAsStateWithLifecycle(initialValue = GenericDetailState())
EvaTheme {
GenericDetailScreen(
settingRows = state.value.settingRows,
onRowSelected = viewModel::onRowSelected,
)
}
}
} Copy code
data class GenericDetailState(
val name: String = "",
val icon: String = "",
val settingRows: List<GenericDetailRow.Settings> = emptyList(),
...
) Copy code
sealed interface GenericDetailRow {
// Used to ensure consistent ordering of rows in the view.
val priority: Int
sealed class Settings : GenericDetailRow {
object GenericSettings : Settings() {
override val priority = 1
}
... Copy code
compose = "2023.06.00"
compose-compiler = "1.5.1"It seems to be related to the
onRowSelected: (GenericDetailRow.Settings) -> UnitRowImageTextArrowz
Zach Klippenstein (he/him) [MOD]
10/11/2023, 7:47 PMIf it’s not recomposing on every frame continuously, I wouldn’t spend a ton of time trying to track a couple extra recompositions. There just isn’t much payoff, and that number could change between versions.
h
Håkon Pettersen
10/12/2023, 6:48 AMGood point @Zach Klippenstein (he/him) [MOD]. I was bothered by not knowing what was triggering the recompositions. After investigating, I discovered it was due to unstable lambdas. To address this, I created a stable interface which is now utilized by the composables
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@Stable
fun interface RowClickListener {
fun selected()
}z
Zach Klippenstein (he/him) [MOD]
10/12/2023, 1:49 PMIs your view model class marked as stable? If so, does passing
{ viewModel.onRowSelected() }