Is there anything wrong in using the `by remember` inside the `composable` function? Without it, the...

# compose

[Luca Nicoletti]

Is there anything wrong in using the by remember inside the composable function? Without it, the edit text field value has a weird behaviour.

class MyState(val text: String)
class MyViewModel(initialState: MyState) {
    internal val mState: MutableStateFlow<MyState> = MutableStateFlow(initialState)
    val state: StateFlow<MyState> = mState.stateIn(
        scope = viewModelScope,
        started = SharingStarted.WhileSubscribed(5000),
        initialValue = initialState,
    )
}

@Composable
fun MyScreenState(state: MyState, onValueChange: (String) -> Unit) {
    var rememberText by remember { mutableStateOf(state.text) }
    OutlinedTextField(
        value = rememberText,
        onValueChange = { rememberText = it; onValueChange(it) }
    )
}

[Luca Nicoletti]

I feel like that remember is an extra-step, forcing us to do things “twice” on the ValueChange callback as well

[abbic]

this looks odd to me, if your state is a stateflow then all you should need to do in your composable is
val state by viewmodel.state.observeAsState()

[Luca Nicoletti]

weird behaviour: typing and cancelling really quickly moves the cursor at random positions, and inputs are messed up

[Luca Nicoletti]

we have that already:

viewModel.state.collectAsState().value

[Luca Nicoletti]

is used as input of the MyScreenState

[abbic]

right

[Stylianos Gakis]

Why do you have two sources of truth regarding what OutlinedTextField shows?
Now you default the rememberText to the intial value of what the VM holds, and then keep a local state from that point on.
Can you show how you had it before you added the by as you say? If you do that maybe it will show why it was having this weird behavior.

[Luca Nicoletti]

Before the remember I had it inlined inside the TextField( value = state.text

[Luca Nicoletti]

But this caused the weird behaviours I wrote above

[Stylianos Gakis]

Since I don’t know exactly how all of your code looked like before by trying to piece things together, I will just say that it may be that this https://medium.com/androiddevelopers/effective-state-management-for-textfield-in-compose-d6e5b070fbe5 is what you were experiencing.
The source of truth from which a TextField should be reading the text from should be mutableState optimally. And in any case, it should hopefully come from 1 source of truth instead of trying to sync one source locally and then one in the VM. Problems with having it in a StateFlow is that if you are introducing any sort of delays from changing it to emitting it you may be giving some delays which are not really supposed to happen with a TextField.
All this is explained in very good detail in this blog. Give it a read and it may be what you are looking for.