backgroundColor property
final
The color of the NavigationBar itself.
If null, NavigationBarThemeData.backgroundColor is used. If that is also null, then if ThemeData.useMaterial3 is true, the value is ColorScheme.surfaceContainer. If that is false, the default blends ColorScheme.surface and ColorScheme.onSurface using an ElevationOverlay.
Implementation
final Color? backgroundColor;