When I m trying to use a custom layout on a composable that contains content i always get an exception This is just an example but it shows my issue I guess im doing something completely wrong here ``` Composable fun Test content Composable gt Unit Box Modifier layout measurable constraints gt layout constraints minWidth constraints minHeight val placeable = measurable measure constraints placeable place 0 0 content Preview Composable fun TestPreview Test Text text = test ```

When I’m trying to use a custom layout on a composable that contains content, i always get an exception. This is just an example, but it shows my issue. I guess im doing something completely wrong here.

@Composable
fun Test(
	content: @Composable () -> Unit
) {
	Box(
		Modifier.layout { measurable, constraints ->
			layout(constraints.minWidth, constraints.minHeight){
				val placeable = measurable.measure(constraints)
				placeable.place(0,0)
			}
		}
	) {
		content()
	}
}

@Preview
@Composable
fun TestPreview() {
	Test(){
		Text(text = "test")
	}
}

Chrimaeon

12/27/2021, 7:38 PM

Can you share the error? I guess you have to measure the measurable outside the layout block

Mikael Alfredsson

12/27/2021, 7:38 PM

ava.lang.IllegalStateException: Measurable could be only measured from the parent's measure or layout block.Parents state is NeedsRelayout

since the modifier only works on one measurable, i guess there is no way to actually override the behaviour for a component that has content [components]?

Chrimaeon

12/27/2021, 7:42 PM

Measurables usually is a list. So you should use for each and move it outside the layout block. So first let the “view” calculate how much space they want do have and then use that information to lay them out.

Mikael Alfredsson

12/27/2021, 7:44 PM

the Modifier.layout only gives one item back (as far as I understand it). For a full Layout component I get a list instead

Chrimaeon

12/27/2021, 7:46 PM

ah, I see. I have never used the modifier. did you follow this https://developer.android.com/jetpack/compose/layouts/custom#layout-modifier the

measure

is still outside the

layout

Mikael Alfredsson

12/27/2021, 7:47 PM

your right, I’ll check

Thanks.

Chrimaeon

12/27/2021, 7:53 PM

Welcome 🙂

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