How to observe current screen in backstack?

[berhram]

For example, in my RootNode I have Scaffold with bottom and top bar. How can I observe what screen in active and recompose my Scaffold each time when screen changed. I tried val scaffoldState = remember(backstack.activeElement) { ... } but it doesn't work (remember doesn't trigger)?

[KovalevAndrey]

Hi @berhram you can implement your own extension that transforms BackStack element into a State like this:

val <T : Any> BackStack<T>.activeElementState: State<T?>
    @Composable
    get() = elements.map { it.activeElement }.collectAsState(initial = null)

and your client code would look like this:

val activeElement by backStack.activeElementState

LaunchedEffect(activeElement) {
    // do something with your active element
}

In the meantime we can add support of this to the library

[berhram]

Thanks!