Is there anything that helps with understanding wh...

# compose

[Alexander Maryanovsky]

Is there anything that helps with understanding what caused a recomposition, or why a @Compose function is not being skipped?

[Thomas Dougherty]

Some notes I shared with my team the other day about Compose recompostuons:

• Make sure any state objects you have only contain val and no var. This should be easy since state is supposed to be immutable anyways.
• If you are using an interface as part of your state object, the interface has to be marked with @Stable or @Immutable so compose knows it can be used for smart recomposition
• Currently Lists passed in trigger recomposition even if immutable. I believe there's a ticket for this to be fixed, one possible solution is to create a holder data class for lists that is marked immutable.
• Implementing a lambda inline with a composable such as Header(onClick = { vm.handleclick() }) will cause recomposition. A few workarounds are:
◦ Hoisting up all unnecessary state and click handlers above the screen and passing them down
◦ Creating an anonymous object in a remember{} that holds all your click functions
◦ If your onClick takes no parameters, using method reference like ::onClick

[Thomas Dougherty]

Some good resources for recomposition:
• https://proandroiddev.com/understanding-re-composition-in-jetpack-compose-with-a-case-study-9e7d96d98095
• https://www.jetpackcompose.app/articles/donut-hole-skipping-in-jetpack-compose
• https://stackoverflow.com/questions/70257459/jetpack-compose-smart-recomposition
• https://issuetracker.google.com/issues/199496149 <- a guy on the issue tracker said that the list bug may be fixed, I personally haven't updated my libraries yet to confirm

[Alexander Maryanovsky]

Thanks, that’s useful, but is there nothing to help with debugging recomposition causes?

[Thomas Dougherty]

As far as I know there's not support for that yet (I could be wrong as this stuff moves fast)

[Alexander Maryanovsky]

Getting recomposition in a function that takes an enum and a Modifier 🤦

[Alexander Maryanovsky]

What do you all think of this suggestion?
https://issuetracker.google.com/issues/216791427

[Alexander Maryanovsky]

At priority P4 someone may look at this again this century. Need more votes.

[Shakil Karim]

i think i heard from @Adam Powell a while ago, about there will be some debugging tools for getting the information which param cause recomposition.

[Jon Boekenoogen]

Can confirm that streamlined tools are in the works.