What does layout builder do in Flutter?

In Flutter, LayoutBuilder Widget is similar to the Builder widget except that the framework calls the builder function at layout time and provides the parent widget’s constraints. This is useful when the parent constrains the child’s size and doesn’t depend on the child’s intrinsic size .

LayoutBuilder helps to create a widget tree in the widget flutter which can depend on the size of the original widget . flutter can take the layout builder as a parameter.

mainAxisAlignment is how items are aligned on that axis. crossAxisAlignment is how items are aligned on the other axis .