How can I close all opened previous screens when click on BottomNavigationBar to open new screen?

Question

How can I close all opened previous screens when click on BottomNavigationBar to open new

screen ?

When I navigate through screens and click on a BottomNavigationBar item

to open a new screen, and after go back to the previous screen, it stays the same as when

I left it.

Does anyone can help me ?

This is my code.

import 'package:flutter/material.dart';
import 'home.dart';
import 'caes.dart';
import 'titulos.dart';
import 'vacinas.dart';
import 'cios.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  final colorFundo = Colors.white;
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
//      localizationsDelegates: [
//        GlobalMaterialLocalizations.delegate,
//        GlobalWidgetsLocalizations.delegate
//      ],
//      supportedLocales: [const Locale('pt', 'BR')],
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        scaffoldBackgroundColor: colorFundo,
      ),
      home: MyBottomNavigationBar(),
    );
  }
}

class MyBottomNavigationBar extends StatefulWidget {
  @override
  State<MyBottomNavigationBar> createState() => _MyBottomNavigationBarState();
}

class _MyBottomNavigationBarState extends State<MyBottomNavigationBar> {
  int _currentIndex = 0;

  final _page1 = GlobalKey<NavigatorState>();
  final _page2 = GlobalKey<NavigatorState>();
  final _page3 = GlobalKey<NavigatorState>();
  final _page4 = GlobalKey<NavigatorState>();
  final _page5 = GlobalKey<NavigatorState>();

  void onTabTapped(int index) {
    setState(() {
      _currentIndex = index;
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: AppBar(
        backgroundColor: Color.fromRGBO(1, 87, 155, 1),
        title: Center(
          child: Text("South Sweet Kennel"),
        ),
        iconTheme: const IconThemeData(color: Colors.black),
      ),
      //body: _children[_currentIndex],
      body: IndexedStack(
        index: _currentIndex,
        children: <Widget>[
          Navigator(
            key: _page1,
            onGenerateRoute: (route) => MaterialPageRoute(
              settings: route,
              builder: (context) => Home(),
            ),
          ),
          Navigator(
            key: _page2,
            onGenerateRoute: (route) => MaterialPageRoute(
              settings: route,
              builder: (context) => CaesPage(),
            ),
          ),
          Navigator(
            key: _page3,
            onGenerateRoute: (route) => MaterialPageRoute(
              settings: route,
              builder: (context) => TitulosPage(),
            ),
          ),
          Navigator(
            key: _page4,
            onGenerateRoute: (route) => MaterialPageRoute(
              settings: route,
              builder: (context) => VacinasPage(),
            ),
          ),
          Navigator(
            key: _page5,
            onGenerateRoute: (route) => MaterialPageRoute(
              settings: route,
              builder: (context) => CiosPage(),
            ),
          ),
        ],
      ),

      bottomNavigationBar: BottomNavigationBar(
        type: BottomNavigationBarType.fixed,
        onTap: (int index) {
          setState(() {
            _currentIndex = index;
          });
        },
        currentIndex: _currentIndex,
        backgroundColor: Color.fromRGBO(1, 87, 155, 1),
        elevation: 15,
        iconSize: 30,
        selectedFontSize: 20,
        selectedIconTheme: IconThemeData(color: Colors.white, size: 40),
        selectedItemColor: Colors.white,
        selectedLabelStyle: TextStyle(fontWeight: FontWeight.bold),
        unselectedIconTheme: IconThemeData(
          color: Colors.lightBlue[200],
        ),
        unselectedItemColor: Colors.white,
        items: const <BottomNavigationBarItem>[
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: 'Home',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.pets),
            label: "Cães",
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.workspace_premium_outlined),
            label: 'Títulos',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.vaccines),
            label: 'Vacinas',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.visibility_outlined),
            label: 'Cios',
          ),
        ],
      ),
    );
  }
}