Hello, Androids! I have an expandable component and I need to know both the height of its expanded a...

# compose

[Lucas Kivi]

Hello, Androids! I have an expandable component and I need to know both the height of its expanded and collapsed states prior to the first layout. I have a semi ugly solution and I am wondering if anyone has anything more graceful! My solution essentially builds an expanded and collapsed instance of the component, measures them, returns the measurements via a callback, and then does not lay them out. If you need me to provide more details I can but the crux of the question is the first sentence: “how can I measure two different states of one component prior to the first layout”.

[jossiwolf]

What's your use case? Why does it need to know the height before layout?
It's a quite nuanced problem so more details would be helpful

[Lucas Kivi]

The variable sized component is the toolbar here:

toolbar.mp4

[Lucas Kivi]

I need these values for setting the anchors for the swipeable bottom sheet.
This is obviously a bare bones toolbar but the real implementation has multiple components that animate as the toolbar expands and collapses.

[Lucas Kivi]

The reason it should know before the first layout is so the bottom sheet can be initialized with the correct anchors

[jossiwolf]

What bottom sheet are we talking about - is it a custom component?

[Lucas Kivi]

it is a custom one!

[Lucas Kivi]

I need four anchors