When using a scaffold with a conditional FAB, I fi...

# compose

[samueldple]

When using a scaffold with a conditional FAB, I find I have to cast to compile:

floatingActionButton = if (condition) { 
    @Composable {
        FloatingActionButton(onClick = {backStack.push(Routing.EditDrink(null))}) {
            Icon(Icons.Default.Add)
        }
    } as @Composable() () -> Unit
} else null

Or I get an "Expected type was Nothing?" error, but when casting the cast shows as a useless cast. Am I doing something stupid?

[Dominaezzz]

What is the declaration of floatingActionButton ?

[samueldple]

floatingActionButton: @Composable (() -> Unit)? = null,

[Dominaezzz]

Shouldn't that be floatingActionButton: (@Composable () -> Unit)? = null ?

[matvei]

Hello! I don't think parenthesis matter, I will try it, thanks.

In the mean time, do you really need to return null?

you can do

floatingActionButton = {
    if (condition) { 
        FloatingActionButton(onClick = {backStack.push(Routing.EditDrink(null))}) {
            Icon(Icons.Default.Add)
        }
}

and it should work just fine

[samueldple]

That worked perfectly, thanks!

[Dominaezzz]

Do the parenthesis not matter?

[samueldple]

I don't think so - they're just there for grouping for the nullibility. Other than that it's just @Composable (() -> Unit) vs @Composable () -> Unit, and in both cases the @Composable applies to the whole function type