how to add drawer in appbar in flutter code example

Example 1: app drawer in flutter

class navigationDrawer extends StatelessWidget {
 @override
 Widget build(BuildContext context) {
   return Drawer(
     child: ListView(
       padding: EdgeInsets.zero,
       children: <Widget>[
         createDrawerHeader(),
         createDrawerBodyItem(
           icon: Icons.home,text: 'Home'),
         createDrawerBodyItem(
           icon: Icons.account_circle,text: 'Profile'),

         createDrawerBodyItem(
           icon: Icons.event_note,text: 'Events'),
         Divider(),
         createDrawerBodyItem(
           icon: Icons.notifications_active,text: 'Notifications'),
         createDrawerBodyItem(
           icon: Icons.contact_phone,text: 'Contact Info'),
         ListTile(
           title: Text('App version 1.0.0'),
           onTap: () {},
         ),
       ],
     ),
   );
 }
}

Example 2: flutter navigation drawer

Widget _createHeader() {  return DrawerHeader(      margin: EdgeInsets.zero,      padding: EdgeInsets.zero,      decoration: BoxDecoration(          image: DecorationImage(              fit: BoxFit.fill,              image:  AssetImage('path/to/header_background.png'))),      child: Stack(children: <Widget>[        Positioned(            bottom: 12.0,            left: 16.0,            child: Text("Flutter Step-by-Step",                style: TextStyle(                    color: Colors.white,                    fontSize: 20.0,                    fontWeight: FontWeight.w500))),      ]));}