I wonder why the `matchParentSize` modifier is ava...

# compose

[Vsevolod Ganin]

I wonder why the matchParentSize modifier is available only in BoxScope? It could be useful in any layout scope I think, as well as matchParentWidth and matchParentHeight

[Timo Drick]

Maybe you want to use the fillMaxSize()/fillMaxHeight/Width() modifier?

[Vsevolod Ganin]

Unfortunately it’s not the same. Here is an example

Column {
    Text(...)
    Canvas(modifier = Modifier.fillMaxWidth().height(1.dp)) {
        drawLine(color, Offset(0f, 0f), Offset(size.width, 0f))
    }
    Text(...)
}

And I get

[Vsevolod Ganin]

While I really don’t want to take Canvas into account while measuring, I just want to set it to be in size as the rest of the content dictates

[Timo Drick]

And when you wrap the Canvas into a Box that have .matchParentSize modifier it works?

[Timo Drick]

Oh sorry. No that will not work

[Timo Drick]

Yea i think you are right. It would be nice to have this modifier in every layout.

[romainguy]

Constraints like match parent available in all layouts unfortunately sometimes leads to ambiguous setups

[romainguy]

An obvious example with the View system is a linear layout set to wrap content and all its children set to match parent

[Adam Powell]

it's not available in every layout because it requires some special handling by the parent, and we don't require that every custom layout perform that special handling.

[Adam Powell]

matchParentSize in Box is an instruction to measure that element last, with whatever specific size the Box has already determined for itself, potentially from measuring its other child elements first.

[Adam Powell]

you can get a similar effect along a single dimension by sizing the container using intrinsic measurements; see this example: https://developer.android.com/codelabs/jetpack-compose-layouts#9

[Timo Drick]

Thanks @Adam Powell
Works:

Column(Modifier.preferredWidth(IntrinsicSize.Min)) {
        Text(text = "4")
        Divider(modifier = Modifier.fillMaxWidth().preferredHeight(1.dp),color = Color.Black)
        Text(text = "2")
    }