Navigation to sub page(nasted Navigation) - flutter

Question

I love to design an app with features like the ones in this Gif
1-Bottom Navigation bar exists on every page(done)
2-pressing on the icon change only part of the page
My Main to move between pages
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int selectedPage = 2;
final _pageOptions = [const PageOne(),const PageTwo(),const PageThree()];
#override
Widget build(BuildContext context) {
return Scaffold(
body: _pageOptions[selectedPage],
bottomNavigationBar: BottomNavigationBar(
items:const [
BottomNavigationBarItem(icon: Icon(Icons.add), label: ""),
BottomNavigationBarItem(icon: Icon(Icons.abc), label: ""),
BottomNavigationBarItem(icon: Icon(Icons.access_alarm), label: ""),
],
onTap: (int index) {
setState(() {
selectedPage = index;
});
},
),
);
}
}
pressing on the icon change only part of the page
Thanks in advance

Answer 1

I used Tabbar in Appbar and use the body of scafoldto change the sub-page
final List<Tab> myTabs = <Tab>[
Tab(text: 'LEFT'),
Tab(text: 'RIGHT'),
];
var Pages=[const PageFour(),const PageFive()];
int pageNum=1;
#override
Widget build(BuildContext context) {
return DefaultTabController(
length: 2,
initialIndex: 1,
child: Scaffold(
appBar: AppBar(
bottom:TabBar(
tabs: myTabs,
onTap: (value) {
setState(() {
pageNum=value;
});
}
),
),
),
)
body: Pages[pageNum],}
I found some solutions using Getx or auto-router but it was difficult to understand it for me as a beginner I hope this answer helps whoever facing the same problem despite I didn't know how to navigate using the page itself as shown in Gif if anyone knows how to do that please answer below.