Coroutine launch is showing error when launched from a composable function. I am trying to show/hide...

# compose

[Ashu]

Coroutine launch is showing error when launched from a composable function. I am trying to show/hide ModalBottomSheetLayout by observing a state flow. How can I resolve this. Also, how do I implement multiple bottom sheets in same Layout?

[Zach Klippenstein (he/him) [MOD]]

What's the error?

[mkrussel]

Are you manually launching and calling collect on the flow inside your composable function.

You should be using https://developer.android.com/reference/kotlin/androidx/compose/runtime/package-summary#(kotlinx.coroutines.flow.StateFlow).collectAsState(kotlin.coroutines.CoroutineContext)

[Ashu]

val hideBottomSheet by hideBottomSheetFlow.collectAsState()

coroutineScope.launch {
    if (hideBottomSheet) bsScaffoldState.hide()
    else bsScaffoldState.show()
}

Here launch is showing "warning error" that Calls to launch should happen inside a LaunchedEffect and not composition

[mkrussel]

You don't need to launch to access data from a state. Just remove the launch. collectAsState does a launch for you inside a LaunchedEffect.

[Zach Klippenstein (he/him) [MOD]]

The ideal approach here is to hoist the scaffold state so that whatever is emitting on hideBottomSheetFlow can just call the show/hide methods itself. If you need to wire up events from a composable like this, you’d want to do something like this:

LaunchedEffect(hideBottomSheetFlow) {
  hideBottomSheetFlow.collect { hideBottomSheet ->
    if (hideBottomSheet) bsScaffoldState.hide() else bsScaffoldState.show()
  }
}

[Zach Klippenstein (he/him) [MOD]]

You don’t need collectAsState here because that flow doesn’t represent state, it’s events.