list view like sliverbuilder in flutter code example

Example 1: flutter listview builder

List litems = ["1","2","Third","4"];
body: new ListView.builder
  (
    itemCount: litems.length,
    itemBuilder: (BuildContext ctxt, int index) {
     return new Text(litems[index]);
    }
  )

Example 2: listviewbuilder flutter firebase

return new ListView.builder( 
    scrollDirection: Axis.vertical, 
    itemCount: snapshot.data.documents.length, 
    itemBuilder: (context, index) { 
        if (index == 0) {
            return someWidget, // return the widget you want as "header" here
        } else {
           return _buildList( context, snapshot.data.documents[index-1]), 
        }
    }
);