What is the BottomNavigationBar widget?
Why Interviewers Ask This
Foundational questions like this help interviewers calibrate the rest of the interview. A confident, accurate answer signals that you have solid Flutter basics — a prerequisite for any developer role.
Answer
BottomNavigationBar displays a row of navigation destinations at the bottom of the screen, following Material Design conventions. It is placed in the bottomNavigationBar slot of a Scaffold. Each destination is a BottomNavigationBarItem with an icon and a label. The currentIndex property tracks the selected tab, and onTap receives the tapped index. For more than 4 items or complex navigation, consider using NavigationBar (Material 3) instead.
Pro Tip
This topic has Flutter-specific nuances that differ from general programming. Highlighting those nuances in your answer shows expertise rather than generic knowledge.