Why is the first

Text

showing the updated text, but not the second

Text

?

@Preview(showBackground = true)
@Composable
fun WithConstraintsComposable() {
    var text: String by remember {
        mutableStateOf("not set")
    }
    Column {
        BoxWithConstraints {
            text = "My minHeight is $minHeight while my maxWidth is $maxWidth"
            Text(text, modifier = Modifier.background(Color.Green))
        }
        Text(text, modifier = Modifier.background(Color.Red))
    }
}

You shouldn't write to state inline in Compose like that where you do

text =

, this is actually probably a backwards write because BoxWithConstraints is a subcompose layout and so runs after the bottom text. https://developer.android.com/jetpack/compose/performance/bestpractices#avoid-backwards

Thanks Ben, that makes sense. My motivation here was to grab some metric from the first item in the column so that it could be used by the second item. I want to do something quite simple: Make sure the second item in the column is no wider that the first item.

Technically, the original example should work, albeit it is not recommended to write to a state from composition. It should update, maybe with a little delay but still.