Recomposition in compose does it go through each node compos kotlinlang #compose

Recomposition in compose - does it go through each node(composable) in the tree and checks if that nodes needs to be updated or not based on last state from slot table?

✅ 1

@Composable
fun MainScreen(viewModel:Vm){
  // live-data in vm
  when (viewModel.response.observeAsState().value) {
    //   
  }

  ScreenContent(
    sate = viewModel.emailState.collectAsState().value,
    onValueChanged: viewModel::valueChanged
  )

}

@Composable
fun ScreenContent(
  state:SomeState,
  onValueChanged:(String) -> Unit
){
  TextField(value = state.text, onValueChange = onValueChanged)
}

Why

MainScreen

Composable, is called(recomposed/invalidated) again when

ScreenContent

is changed. I believe only

ScreenContent

should be recomposed in this case.

Adam Powell

03/06/2022, 3:35 AM

ScreenContent

isn't what's reading the

.value

of the snapshot state objects being invalidated,

MainScreen

ritesh

03/06/2022, 3:45 AM

Thanks Adam, i was under the assumption that

re-composition

is based on parameters passed down in the tree hierarchy, and if there is a difference from last state, only that composable will re-compose, not the parent node.

Adam Powell

03/06/2022, 3:54 AM

a parameter's value is controlled by the caller. For a parameter to change the caller must run to pass a new value

👍 2

ritesh

03/06/2022, 10:25 PM

a parameter's value is controlled by the caller. For a parameter to change the caller must run to pass a new value

also, this article by Zach cleared my doubts related to node invalidation

👍 1

9 Views

#compose Join Slack