Trying to add a pageview controller without success....completely new at this - flutter

Question

I am completely new at coding and of course I am trying to tackle one of the largest projects I can think of.... anyways. I am running into a huge wall when it comes to my current stage of coding. I have a defaultTabController at the upper portion of the screen with the functionality to switch in between two tabs. I would also like to have a bottomNavigationBar at the bottom of the application with 5 buttons that navigate to additional pages.
I have been attempting to add this code PageView(controller: _pageController, children: <Widget>[],) to the body of my code, yet I am either getting an overload of errors or only the top or bottom nav bars are active. If someone could show me what I'm doing wrong, I would be so grateful!
class HomeScreen extends StatefulWidget {
#override
_HomeScreenState createState() => _HomeScreenState();
}
class _HomeScreenState extends State<HomeScreen> {
int _currentTab = 0;
PageController _pageController;
#override
void initState() {
super.initState();
_pageController = PageController();
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: DefaultTabController(
length: 2,
child: Scaffold(
extendBodyBehindAppBar: true,
extendBody: true,
appBar: AppBar(
backgroundColor:
Colors.grey.withOpacity(0.5),
title: Text(
'TREBLE',
style: TextStyle(
color: Colors.black,
fontFamily: "treblefont",
fontSize: (33.0)
),
),
bottom: TabBar(
tabs: <Widget>[
Tab(text: "Following"),
Tab(text: "trending"),
],
)
),
body:
TabBarView(
children: <Widget>[
FeedScreen(),
TrendingScreen(),
],
),
bottomNavigationBar: CupertinoTabBar(
currentIndex: _currentTab,
onTap: (int index) {
setState(() {
_currentTab = index;
});
},
activeColor: Colors.black,
backgroundColor: Colors.white.withOpacity(0.5),
items: [
BottomNavigationBarItem(
icon: Icon(
Icons.home,
size: 32.0,
),
),
BottomNavigationBarItem(
icon: Icon(
Icons.search,
size: 32.0,
),
),
BottomNavigationBarItem(
icon: Icon(
Icons.camera_enhance,
size: 32.0,
),
),
BottomNavigationBarItem(
icon: Icon(
Icons.notifications,
size: 32.0,
),
),
BottomNavigationBarItem(
icon: Icon(
Icons.account_circle,
size: 32.0,
),
),
],
),
),
),
);
}
}
I attempt to insert the code here:
)
),
body:
PageView(controller: _pageController, children: <Widget>[],)
TabBarView(
children: <Widget>[
FeedScreen(),
TrendingScreen(),
],
),
bottomNavigationBar: CupertinoTabBar(
currentIndex: _currentTab,
onTap: (int index) {
setState(() {
_currentTab = index;
});
},
line of code screenshot
Specific error readout screenshot