A builder to customize the dropdown buttons corresponding to the
DropdownMenuItems in items.
When a DropdownMenuItem is selected, the widget that will be displayed
from the list corresponds to the DropdownMenuItem of the same index
This sample shows a
with a button with Text
corresponds to but is unique from DropdownMenuItem
To create a local project with this code sample, run:
flutter create --sample=material.DropdownButton.selectedItemBuilder.1 mysample
If this callback is null, the DropdownMenuItem from items
that matches value will be displayed.
final DropdownButtonBuilder? selectedItemBuilder;