buildResponderRow.dart

 Widget _buildResponderRow(List<Responder> group) {
    return Container(
      height: 100.0,
      child: ListView.builder(
        itemCount: group.length,
        scrollDirection: Axis.horizontal,
        itemBuilder: (context, index) {
          return _buildResponderView(group[index]);
        },
      ),
    );
  }