bottom appbar elevation plus rounded

bootomAppBar.dart

bottomNavigationBar: Padding(
        padding: const EdgeInsets.all(8.0),
        child: Container(
          decoration: BoxDecoration(boxShadow: [
            BoxShadow(
              blurRadius: 4.0,
              offset: Offset(0.0, 0.0),
              color: Colors.grey,
            ),
          ], borderRadius: BorderRadius.circular(36.0)),
          child: ClipRRect(
            borderRadius: BorderRadius.circular(36.0),
            child: BottomAppBar(
              // elevation: 8.0,
              // shape:
              color: Colors.white,
              child: IconTheme(
                data: IconThemeData(
                    color: Theme.of(context).colorScheme.onPrimary),
                child: Row(
                  children: [
                    IconButton(
                      tooltip: 'Open navigation menu',
                      icon: const Icon(
                        Icons.settings,
                        color: Colors.blue,
                      ),
                      onPressed: () {},
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }