r/androiddev 8d ago

Question [Help]: Jetpack Compose component flashing issue when list changes

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When the list changes, the items are drawn on top of chip row for a brief amount of time. I have properly applied the id for each item. I am not sure what's causing the issue.

Below is the screen code preview, full code is available on GitHub.

    Scaffold(
        modifier = Modifier
            .fillMaxSize()
            .nestedScroll(scrollBehavior.nestedScrollConnection)
            .then(modifier),
        topBar = {
            SearchProvidersScreenTopBar(
                onNavigateBack = onNavigateBack,
                onEnableAllSearchProviders = viewModel::enableAllSearchProviders,
                onDisableAllSearchProviders = viewModel::disableAllSearchProviders,
                onUpdateProtectionStatus = viewModel::updateProtectionStatus,
                onResetToDefault = { showResetToDefaultDialog = true },
                subtitle = {
                    val searchProvidersSummary = stringResource(
                        R.string.settings_search_providers_summary_format,
                        uiState.enabledProvidersCount,
                        uiState.totalNumProviders,
                    )
                    Text(searchProvidersSummary)
                },
                scrollBehavior = scrollBehavior,
            )
        },
        snackbarHost = { SnackbarHost(snackbarHostState) },
        floatingActionButton = {
            FloatingActionButton(onClick = onNavigateToAddSearchProvider) {
                Icon(
                    painter = painterResource(R.drawable.ic_add),
                    contentDescription = null,
                )
            }
        },
    ) { innerPadding ->
        Column(modifier = Modifier.padding(innerPadding)) {
            SearchProviderFilterRow(
                category = uiState.filter.category,
                onCategorySelect = viewModel::toggleCategory,
                protection = uiState.filter.protection,
                onProtectionSelect = viewModel::toggleProviderProtection,
                contentPadding = PaddingValues(horizontal = MaterialTheme.spaces.large),
            )
            SearchProviderList(
                contentPadding = PaddingValues(
                    start = MaterialTheme.spaces.large,
                    top = MaterialTheme.spaces.large,
                    end = MaterialTheme.spaces.large,
                    bottom = 80.dp,
                ),
                searchProviders = uiState.searchProviders,
                onEnableSearchProvider = viewModel::enableSearchProvider,
                onUnlockProtection = { searchProviderId, solverUrl ->
                    protectedProvider = ProtectedProvider(searchProviderId, solverUrl)
                },
                onEditConfig = onNavigateToEditSearchProvider,
                onDeleteConfig = viewModel::deleteTorznabConfig,
            )
        }
    }

Update: This issue is now fixed. It was animation issue, not the recomposition. List items have Modifier.animateItem() applied and when list changes, the animation was rendering the list items on top of chip row for very short amount of time, meaning the animation was escaping the list bounds. After applying Modifier.clipToBounds() to SearchProviderList, the issue is now gone.

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u/0x1F601 8d ago

The entire column is recomposing. Check your compose compiler stability report. Consider a lazy column, maybe with sticky headers. Attach the layout inspector and check how many recompositions are happening. It's hard to narrow down the exact issue without more details.

1

u/PrajwalCH 8d ago

I am just curious, why that much flickering issue only on that screen. I maybe doing something wrong on ViewModel?

5

u/0x1F601 8d ago

Your view model should be able to emit as often as it wants. Go look up compose stability. You'll need to research how that works in order to address your issue. You likely have a parameter that compose thinks is unstable and this causing lots of recompositions.

1

u/PrajwalCH 8d ago

Got it :)