Anyone know what the status is on shared element transitions in compose navigation ?

# compose

[nlindberg]

Anyone know what the status is on shared element transitions in compose navigation ?

[Jakub Syty]

Early stages, but you can experiment with this: https://github.com/skydoves/Orbital

[nlindberg]

Is the Orbital lib in anyway related to what is being worked on in accompanist?

[Jakub Syty]

i don't think so, it's related to LookaheadLayout

[nlindberg]

Aight thanks, will check it out 👍

[Ian Lake]

LookaheadLayout has been ~superceded by usages of LookaheadScope as part of yesterday's release https://developer.android.com/jetpack/androidx/releases/compose-animation#1.5.0-alpha02 (see for example the example experiment at https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]mpose/animation/demos/lookahead/AnimateBoundsModifier.kt;l=47 which implements animating the bounds of a view with just a modifier)

[Ian Lake]

That LookaheadScope part is what needs to be applied to APIs like AnimatedContent first. That would allow shared elements between screens you display in AnimatedContent

[Ian Lake]

And it is AnimatedContent that powers Accompanist Navigation Compose, so as soon as AnimatedContent gains such super powers, so will the Navigation Compose integration

[NielsLindberg]

Thanks a lot for the update Ian, is there any issue tracker or similar where we can follow the status on Accompanist or AnimatedContent?

[Ian Lake]

https://issuetracker.google.com/issues/202470191 is the issue for supporting shared elements, which would include up through AnimatedContent

[Ian Lake]

And https://issuetracker.google.com/issues/197140101 is for moving Accompanist Navigation Animation back into Navigation Compose itself (which is possible now that AnimatedContent is no longer experimental - it'll be part of the Navigation 2.7 release)

[NielsLindberg]

Aight looking forward to the new features 🎂 Will there be lots of API changes compared to how Accompanist Navigation is now?

[Ian Lake]

I don't know - do you like the Accompanist Navigation API? 🙂

[NielsLindberg]

😄 Was more out of a sense of curiosity on how it will change. I'm not very attached to it, as long as I can create UI flows with shared elements i'm happy 😁

[Ian Lake]

ha, no changes expected, but everything is tbd until we see what the shared element API looks like

[Ian Lake]

I'd love a Modifier based approach though, ala https://kotlinlang.slack.com/archives/CJLTWPH7S/p1654836389534839?thread_ts=1654793995.106589&cid=CJLTWPH7S

[Ian Lake]

Which would preclude needing specific APIs at the Navigation level

[NielsLindberg]

Read through the thread you linked, I like the modifier approach as well. Is there any of these changes that would make having shared elements in a nested graph ?

e.g. on the official example:

NavHost(navController, startDestination = "home") {
    ...
    // Navigating to the graph via its route ('login') automatically
    // navigates to the graph's start destination - 'username'
    // therefore encapsulating the graph's internal routing logic
    navigation(startDestination = "username", route = "login") {
        SharedElementLoginLevel()
        composable("username") { ... }
        composable("password") { ... }
        composable("registration") { ... }
    }
    ...
}

So a shared element between all login routes.