Im having some animation issues, my intention is t...

# compose

[Zoltan Demant]

Im having some animation issues, my intention is to slide in a piece of content over the current; but if the piece is running animations itself, the sliding animation breaks. 🧵👀

[Chris Sinco [G]]

Hmm what APIs are you using? Have you tried AnimatedContent?

[Zoltan Demant]

I think it happens due to the piece switching its contents, crossfading between a loading indicator and its actual contents the first time around. The sliding animation runs perfectly when the piece no longer starts off with its loading indicator. I thought the contentKey would solve this, but it seems that it doesnt.

Any clues on how I can make it work? Related discussion.

This is what the piece animation looks like:

val transition = updateTransition(
            targetState = content,
            label = null
        )

        transition.Crossfade(
            contentKey = { content ->
                content != null 
            },
            animationSpec = spring(
                stiffness = Spring.StiffnessMediumLow,
                visibilityThreshold = 0.01f
            ),
            content = { content ->
                when {
                    content != null -> {
                        Render(content)
                    }
                    else -> {
                        Loading()
                    }
                }
            }
        )

[Zoltan Demant]

I think I figured it out! Ironic how Ive been looking into this forever, and only managed to find the solution after posting about it 🤷🏽‍♂️

Since Im rendering a backstack, I only want to animate changes to its size. For cases where the difference is 0, I specify a `ContentTransform(None)`; but that seems to also snap the current animation to its end values, which is the case when the loading-to-content transition is running during this animation.

Specifying the same animation for cases where the difference >= 0 (instead of >0) seems to solve this!