How to use the constraints and sizes of other widgets during the build phase

Question

I want to make sure I cover all cases

1. A Parent widget reads (and possibly uses) a child\'s size or constraints

2. A Child widget reads (and po

Answer 1

Widgets can't do such thing on purpose. A Widget should never depend on the size and position or anything. Not even their children.

If you ever face a situation where you need to, LayoutBuilder should be fine most of the time.

If it's not, what you want to create isn't a Widget. But a RenderObject instead, one of the lower layer of flutter.

Widgets such as Center, Stack or Column are in fact computed using RenderObject.