IssueTracker

A problem I had was passing the insets to a LazyColumn. The LazyColumn was sometimes under the insets and so needed the insets given as its contentPadding parameter. In tablet mode the LazyColumn wasn't under the navigation bar and a parent consumed the insets, but there was no easy way to pass that info to the LazyColumn. The only alternative that I can see is to have the parent that consumed the insets to calculate what the child insets should be manually and then to pass the insets down the tree to where the LazyColumn is. This seems like reinventing the ModifierLocal that handles the consumed insets when it would be easier if that info could be accessed directly.

Thank you. It doesn't look like this will be a trivial solution as yet. However, one of our team members is just now adding a feature that will make this possible. Because the feature is going to be experimental API, we likely won't be able to use it in the foundation library for a few months.

One potential workaround is applying a windowInsetsPadding or windowInsets*Height to an item inside the LazyColumn, as opposed to using contentPadding (since that allows using the ModifierLocal normally. But that may not always be an option (or that has other non-desirable effects).

Any solution that involves composition means that layout will be delayed by 1 frame.

For the above problem, I think we need something like this:

val consumedNavigationBars by remember { MutableWindowInsets() }
Box(
        modifier = Modifier
            .consumedWindowInsets(WindowInsets.navigationBars)
            .withConsumedWindowInsets {
                consumedNavigationBars.insets = WindowInsets.navigationBars.exclude(it)
            }
    ) {
        // will have non-zero insets
        val insets = consumedNavigationBars.asPaddingValues()
    }

class MutableWindowInsets : WindowInsets {
    var insets by mutableStateOf(WindowInsets(0, 0, 0, 0))
    fun getLeft(density: Density, layoutDirection: LayoutDirection): Int = insets.getLeft(density, layoutDirection)
    fun getTop(density: Density): Int = insets.getTop(density)
    fun getRight(density: Density, layoutDirection: LayoutDirection): Int = insets.getRight(density, layoutDirection)
    fun getBottom(density: Density): Int = insets.getBottom(density)
}

This bug was linked in a change in the following release(s):

• androidx.compose.foundation:foundation-layout:1.3.0-beta03