Scratching my head. I'm copy/pasting some previous...

# getting-started

[Travis Griggs]

Scratching my head. I'm copy/pasting some previous code I prototyped, using a LazyColumn and the items() builder like so:

items(items = sortedPlans, key = { plan -> plan.oid })

oid is just a UInt. However, this fails. Digging through Logcat, I find this gem:

java.lang.IllegalArgumentException: Type of the key 2 is not supported. On Android you can only use types which can be stored inside the Bundle.

Going back and looking at what I was doing before, I actually had a Pair there. So I just changed the above code to first:

items(items = sortedPlans, key = { plan -> 'p' to plan.oid })

and that worked!?! As did this:

items(items = sortedPlans, key = { plan -> plan.oid.toInt() })

What strange magic is this? I can't use a UInt? But I can if I wrap it in a pair? Why would that be the case?

[ephemient]

kotlin.Pair implements java.io.Serializable on JVM, which makes it pass the saveable test

[ephemient]

of course it'll fail at runtime because the UInt wrapper class isn't serializable, but the generic Pair class can't know that

[Travis Griggs]

But it didn't fail at runtime, it worked

[ephemient]

it doesn't get saved actually saved to a bundle until the app need to be stopped

[Travis Griggs]

like on a rotate?