RippleAlpha

Class

Common

public class RippleAlpha(
    public val draggedAlpha: Float,
    public val focusedAlpha: Float,
    public val hoveredAlpha: Float,
    public val pressedAlpha: Float,
)

RippleAlpha defines the alpha of the ripple / state layer for different Interactions.

On Android, because the press ripple is drawn using the framework's RippleDrawable, there are constraints / different behaviours for the actual press alpha used on different API versions. Note that this only affects pressedAlpha - the other values are guaranteed to be consistent, as they do not rely on framework code. Specifically:

API 21-27: The actual ripple is split into two 'layers', with the alpha applied to both layers, so there is no uniform 'alpha'. API 28-32: The ripple is just one layer, but the alpha is clamped to a maximum of 0.5f - it is not possible to have a fully opaque ripple. API 33: There is a bug where the ripple is clamped to a minimum of 0.5, instead of a maximum like before - this should be resolved in future versions.