What is the difference or what would the reasoning be behind using rememberScaffoldState as a peramitor instead of in the function itself. Such as... @Composable fun MyScreen( state: UiState<List<Movie>>, scaffoldState: ScaffoldState = rememberScaffoldState() ) { // Instead of // val scaffoldState = rememberScaffoldState() // If the UI state contains an error, show snackbar if (state.hasError) { //

LaunchedEffect

will cancel and re-launch if //

scaffoldState.snackbarHostState

changes LaunchedEffect(scaffoldState.snackbarHostState) { // Show snackbar using a coroutine, when the coroutine is cancelled the // snackbar will automatically dismiss. This coroutine will cancel whenever //

state.hasError

is false, and only start when

state.hasError

is true // (due to the above if-check), or if

scaffoldState.snackbarHostState

changes. scaffoldState.snackbarHostState.showSnackbar( message = "Error message", actionLabel = "Retry message" ) } } Scaffold(scaffoldState = scaffoldState) { /* ... */ } }

This is useful when you want to keep track of the changes in that scaffold state higher up in your hierarchy. So for example, passing

MutableInteractionSource

to a button lets you "inject" interactions to emulate programmatic changes to the pressed / hovered / focused / ... state. Or to pass a

ScrollState

and then programmatically call

animateScrollTo

based on a certain condition - outside the specific inner logic of that scrollable component.

Whoa whoa whoa, lol my brain is still hurting from the last thing I learned. Could you use an example with scaffold state? The relevancy would help me put the why with the when.

Sorry, I haven't worked with that particular component yet. But that's the idea, to have sort of a communication channel between the "parent" and the "child" composable beyond the data state.

So would you ever want to do that with navcontroller? I guess what I'm most confused with is if for example @Composable fun ANavControler() Val navcontroller = rememberNavcontroller() NavHost(navController) @Composable fun someScreen(navController: Navcontroller) @Composable fun anotherScreen(navcontroller = rememberNavController) What is the difference? In some screen is it recieving the remembered navcontroller and anotherScreen isn't? Would there ever be a reason to do it like anotherScreen? The only examples I've seen have never used it with navcontroller why is that?

The difference between

someScreen

and

anotherScreen

is that the first one requires you to pass a controller, and the second one provides a default one if you don't need that communication channel and are OK with that default.

Ohhhhh...  🤯