TIL of produceState <https://developer.android.com/develop/ui/compose/side-effects#producestate> Is ...

# compose-android

[Colton Idle]

TIL of produceState https://developer.android.com/develop/ui/compose/side-effects#producestate
Is that something that people use often? Not sure how I missed it for the past 2 years lol

[Stylianos Gakis]

If you were gonna make a mutable state and then start populating it from a launched effect. Then you do this instead 😅
Here's an example https://github.com/HedvigInsurance/android/blob/develop/app%2Ffeature%2Ffeature-claim-details%2Fsrc%2Fmain%2Fkotlin%2Fcom%2Fhedvig%2Fandroid%2Ffeature%2Fclaim%2Fdetails%2Fui%2FSubmittedAndClosedColumns.kt#L78-L85

But it's definitely kinda niche.

[Francesc]

you can think of it as the opposite of snapshotFlow

[Zach Klippenstein (he/him) [MOD]]

isn’t any snapshot state implementation the opposite of snapshotFlow?

[Sergey Y.]

I use 🫡

[Joel Denke]

If I remember correct, LaunchedEffect using produceState. I used produceState for example rendering pdf in compose or any async state.

[Stylianos Gakis]

It’s the other way around https://cs.android.com/androidx/platform/frameworks/support/+/androidx-main:compose/[…]droidx/compose/runtime/ProduceState.kt;l=76-86?q=produceState
produceState is just a convenience over doing what I said here.

[Joel Denke]

Right, Thanks mixed it up 😁

[Marcin Wisniowski]

I like it for having a “current time” state.
Something like val now = produceState(Instant.now()) { while (true) { delay(333) value = Instant.now() } }
For example for a timestamp text that shows “2 mins ago” and should update itself automatically.