[Question] Why not pass topbar as a parameter to Scaffold

[shdmfire]

Why not pass topbar as a parameter to Scaffold?

• I'm also trying a single top level Scaffold, but there are different implementations for topbar and floatingActionButton for different Screens, and the method that needs to be called for clicking on the topbar/floatingActionButton is likely to be the corresponding Screen's state switching , I don't know how to correctly pass that state switching method to the top level Scaffold

While looking up the official specification, I found the code for this project:

        Scaffold(
            modifier = modifier.semantics {
                testTagsAsResourceId = true
            },
            containerColor = Color.Transparent,
            contentColor = MaterialTheme.colorScheme.onBackground,
            contentWindowInsets = WindowInsets(0, 0, 0, 0),
            snackbarHost = {
                SnackbarHost(
                    snackbarHostState,
                    modifier = Modifier.windowInsetsPadding(
                        WindowInsets.safeDrawing.exclude(
                            WindowInsets.ime,
                        ),
                    ),
                )
            },
        ) { padding ->
            Column(
                Modifier
                    .fillMaxSize()
                    .padding(padding)
                    .consumeWindowInsets(padding)
                    .windowInsetsPadding(
                        WindowInsets.safeDrawing.only(
                            WindowInsetsSides.Horizontal,
                        ),
                    ),
            ) {
                // Show the top app bar on top level destinations.
                val destination = appState.currentTopLevelDestination
                var shouldShowTopAppBar = false

                if (destination != null) {
                    shouldShowTopAppBar = true
                    NiaTopAppBar(
                        titleRes = destination.titleTextId,
                        navigationIcon = NiaIcons.Search,
                        navigationIconContentDescription = stringResource(
                            id = settingsR.string.feature_settings_top_app_bar_navigation_icon_description,
                        ),
                        actionIcon = NiaIcons.Settings,
                        actionIconContentDescription = stringResource(
                            id = settingsR.string.feature_settings_top_app_bar_action_icon_description,
                        ),
                        colors = TopAppBarDefaults.topAppBarColors(
                            containerColor = Color.Transparent,
                        ),
                        onActionClick = { onTopAppBarActionClick() },
                        onNavigationClick = { appState.navigateToSearch() },
                    )
                }

Why do we need to do this? According to the official specification, we need to pass the topbar as a parameter to Scaffold.