Why doesn't dimensionResource in Jetpack Compose use remember, and what happens if we add it?

Javad Vatan — Sun, 02 Feb 2025 10:12:23 +0000

In Jetpack Compose, we use **dimensionResource **to retrieve a dimension value from resources and convert it to Dp. The built-in function is defined as:

@Composable @ReadOnlyComposable fun dimensionResource(@DimenRes id: Int): Dp { val context = LocalContext.current val density = LocalDensity.current val pxValue = context.resources.getDimension(id) return Dp(pxValue / density.density) }

This function does not use remember.

My questions:

Why doesn't dimensionResource internally use remember to cache the
result and prevent redundant recomputation during recomposition?
What would happen if I wrapped it in remember like this?

@Composable fun rememberedDimensionResource(@DimenRes id: Int): Dp { val context = LocalContext.current val density = LocalDensity.current return remember(id) { val pxValue = context.resources.getDimension(id) Dp(pxValue / density.density) } }

Would this improve performance by avoiding unnecessary resource lookups, or is there a reason why dimensionResource is designed without remember?

I'm trying to understand the implications of caching dimension values in Jetpack Compose and whether this would provide a real optimization.

Any insights would be greatly appreciated.

DEV Community: Javad Vatan

Why doesn't dimensionResource in Jetpack Compose use remember, and what happens if we add it?