Firstly, let’s set up the object class for drawer items:

class DrawerItem {
 String title;
 IconData icon;
 DrawerItem(this.title, this.icon);
}

Next, the essential variables:

int _selectedDrawerIndex = 0;

final _drawerItems = [
  DrawerItem(“Pizza”, Icons.local_pizza),
  DrawerItem(“Drink”, Icons.local_drink),
];

Then, we need to build the navigation items:

List<Widget> _buildNavigationItems()
{
  List<Widget> list = [];

  for (int i=0; i < _drawerItems.length; i++)
  {
    list.add(ListTile(
      leading: Icon(_drawerItems[i].icon),
      title: Text(
        _drawerItems[i].title,
        style: TextStyle(fontSize: 16.0),
      ),
      selected: i == _selectedDrawerIndex,
      onTap: () => _onItemSelected(i),
    ));
  }

  return list;
}

_onItemSelected(int index) {
  setState(() => _selectedDrawerIndex = index);
  Navigator.of(context).pop();
}

Lastly, a method to set the page according to the index selected in the drawer:

_getPage(int index) {
  switch (index) {
    case 0:
      return First(); // from first.dart
    case 1:
      return Second(); // from second.dart
  }
}

The full code is available below.