Flutter Bottom Navigaton

Question

I want bottom navigation to change if I press any button or link on other tab. For example

If I am on this page and I click on "weekdays" list item, I go to this next page.

Now, my first page is in "Home" tab and my second page is in "Configuration" tab. How do I switch the tab while showing user this page? my origin page for "Configuration" tab is this next one.

My code for bottomNavigation bar is this.

index.dart

import 'package:flutter/material.dart';
import 'package:soneilcharging/Pages/settings/settings.dart';
import 'package:soneilcharging/tabNavigator.dart';

// functional widgets
import 'Pages/home.dart';
import 'Pages/configuration/configuration.dart';
import 'Pages/record/records.dart';
import 'Pages/scheduling/schedule.dart';

// welcome page

// navigation

class indexWidget extends StatefulWidget {
  const indexWidget({Key? key}) : super(key: key);

  @override
  State<indexWidget> createState() => _indexWidgetState();
}

class _indexWidgetState extends State<indexWidget> {
  int _selectedIndex = 0;
  String _currentPage = "Home";
  PageController pageController = PageController();
  List<String> pageKeys = ["Home", "Configuration", "History"];
  Map<String, GlobalKey<NavigatorState>> _navigatorKeys = {
    "Home": GlobalKey<NavigatorState>(),
    "Configuration": GlobalKey<NavigatorState>(),
    "History": GlobalKey<NavigatorState>(),
  };

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
  }

  void _onItemTapped(int index) {
    _selectTab(pageKeys[index], index);
    /* pageController.animateToPage(index,
        duration: Duration(milliseconds: 500), curve: Curves.ease); */
  }

  void pageChanged(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }

  Widget _buildOffstageNavigator(String tabItem) {
    return Offstage(
      offstage: _currentPage != tabItem,
      child: TabNavigator(
        navigatorKey: _navigatorKeys[tabItem]!,
        tabItem: tabItem,
      ),
    );
  }

  void _selectTab(String tabItem, int index) {
    if (tabItem == _currentPage) {
      _navigatorKeys[tabItem]!.currentState!.popUntil((route) => route.isFirst);
    } else {
      setState(() {
        _currentPage = pageKeys[index];
        _selectedIndex = index;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return WillPopScope(
      onWillPop: () async {
        final isFirstRouteInCurrentTab =
            !await _navigatorKeys[_currentPage]!.currentState!.maybePop();
        if (isFirstRouteInCurrentTab) {
          if (_currentPage != "Home") {
            _selectTab("Home", 0);

            return false;
          }
        }
        // let system handle back button if we're on the first route
        return isFirstRouteInCurrentTab;
      },
      child: Scaffold(
        bottomNavigationBar: BottomNavigationBar(
          backgroundColor: Colors.black,
          items: const <BottomNavigationBarItem>[
            BottomNavigationBarItem(
              icon: Icon(Icons.home),
              label: 'Home',
              backgroundColor: Colors.black,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.schedule),
              label: 'Configuration',
              backgroundColor: Colors.black,
            ),
            BottomNavigationBarItem(
              icon: Icon(Icons.history),
              label: 'History',
              backgroundColor: Colors.black,
            ),
          ],
          currentIndex: _selectedIndex,
          unselectedItemColor: Colors.grey,
          onTap: _onItemTapped,
          type: BottomNavigationBarType.fixed,
          fixedColor: Colors.white,
          iconSize: 20,
        ),
        body: Stack(
          children: [
            _buildOffstageNavigator("Home"),
            _buildOffstageNavigator("Configuration"),
            _buildOffstageNavigator("History"),
          ],
        ),
      ),
    );
  }
}

tabNavigator.dart

import 'package:flutter/material.dart';
import 'package:soneilcharging/Pages/home.dart';

import 'Pages/record/records.dart';
import 'Pages/scheduling/schedule.dart';

class TabNavigatorRoutes {
  static const String root = '/';
  static const String detail = '/detail';
}

class TabNavigator extends StatelessWidget {
  final GlobalKey<NavigatorState> navigatorKey;
  final String tabItem;
  TabNavigator({required this.navigatorKey, required this.tabItem});

  @override
  Widget build(BuildContext context) {
    Widget? child;
    if (tabItem == "Home") {
      child = HomeWidget(onButtonPressed: () => {});
    } else if (tabItem == "Configuration") {
      child = const scheduleWidget();
    } else if (tabItem == "History") {
      child = const Records();
    }

    return Navigator(
      key: navigatorKey,
      onGenerateRoute: (routeSettings) {
        return MaterialPageRoute(builder: (context) => child!);
      },
    );
  }
}

And the way I am navigating from my settings page to schedule page is this:

Navigator.of(context).push(createRoute(departureWidget(
                                    pageMod: PageModeSched.Edit,
                                    editSetTimes: setTimes,
                                    editViewTimes: viewListTimes,
                                    editIndex: index,
                                  )))
                                  .then((value) => {
                                        isScheduleCharge = true,
                                        setState(
                                          () => {},
                                        )
                                      });

Any Idea how do I do this? I only want my schedule page to have single instance throughout the app. Currently, home tab creates its own version and configuration tab creates its own version.