```@OptIn(ExperimentalMaterialApi::class) private ...

# compose

[ursus]

@OptIn(ExperimentalMaterialApi::class)
private val MyRippleConfiguration =
    RippleConfiguration(color = Color.Red, rippleAlpha = MyRippleAlpha)

In the docs the ripple config instance is cached (in a top level val)

what is the preferred way to cache this if the given color comes from Material.colors which is @Composable?

I cannot just access Color.x statically like they do

The color is effectivelly static all time, so having a single instance for all is reasonable, but remember { .. } probably doesn' make much sense, since that would scope it to composition, and I have multiple components that need this at the same time

[Louis Pullen-Freilich [G]]

This seems more like you are trying to change ripple behavior across your application, LocalRippleConfiguration is more for specific per component overrides, it isn’t intended to be used to define complex theming logic.

Material ripples use LocalContentColor - if this doesn’t work for you at an app-wide level, then you probably would be better off building your own ripple / components that use your ripple

[Louis Pullen-Freilich [G]]

https://developer.android.com/develop/ui/compose/touch-input/user-interactions/migrate-indication-ripple#globally-change-ripples

There’s some more information here

[ursus]

No no, I'm creating a SelectableCard which is a wrapper around Card which adds border when selected - and the border is blue, so I want the ripple to be blue as well

Only for this one component

[ursus]

@OptIn(ExperimentalMaterialApi::class)
@Composable
fun SelectableCard(
    modifier: Modifier = Modifier,
    selected: Boolean,
    enabled: Boolean = true,
    backgroundColor: Color = MaterialTheme.colors.surface,
    onClick: () -> Unit,
    content: @Composable () -> Unit
) {
    val strokeColor = if (selected) {
        MaterialTheme.colors.secondary
    } else {
        MaterialTheme.colors.whatever
    }
    CompositionLocalProvider(
        LocalRippleConfiguration provides RippleConfiguration(
            color = MaterialTheme.colors.secondary
        ),
    ) {
        Card(
            onClick = onClick,
            modifier = modifier,
            border = BorderStroke(1.dp, SolidColor(value = strokeColor)),
            backgroundColor = backgroundColor,
            elevation = 0.dp,
            content = content
        )
    }
}

all there is to it

and the question is now how should I cache the RippleConfiguration instance, or if I should at all?

[Louis Pullen-Freilich [G]]

I see, I don’t think there’s much value in caching it then

[ursus]

(I simplified the snippet now)

[Louis Pullen-Freilich [G]]

It’s just a simple class, so it should be ok to create a new one when the theme colors change

[ursus]

okay so some sort of lazy-init caching is not work much?

[ursus]

okay great thank you

[Louis Pullen-Freilich [G]]

given that the ripple configuration object is just a simple class with two properties, any caching you try and do is probably going to be more expensive than just creating a new one