How to refresh state in the Bottom Navigation Bar

Question

I'm using a IndexedStack for my BottomNavigationBar(BNB) and I want to refresh the state of the Screen whenever I press it. If I select Screen2 for example, I want to refresh the state again, at this point it is only storing current state and it shows the screen on the initial state when I call the BNB widget. Since it is a stack, it only shows the screen that is clicked, but I want to refresh the state of that screen every time I press on it. Here is the code:

import 'package:flutter/material.dart';

class BottomNavBar extends StatefulWidget {
  static const String id = 'bottom_navbar_screen';
  @override
  _BottomNavBarState createState() => _BottomNavBarState();
}

class _BottomNavBarState extends State<BottomNavBar> {

  int _selectedIndex = 0;

  /// list of screen that will render inside the BNB
  List<Navigation> _items = [
    Navigation(
        widget: Screen1(), navigationKey: GlobalKey<NavigatorState>()),
    Navigation(
        widget: Screen2(), navigationKey: GlobalKey<NavigatorState>()),
    Navigation(
        widget: Screen3(), navigationKey: GlobalKey<NavigatorState>()),
  ];

  /// function that renders components based on selected one in the BNB

  void _onItemTapped(int index) {
    if (index == _selectedIndex) {
      _items[index]
          .navigationKey
          .currentState
          .popUntil((route) => route.isFirst);
    } else {
      setState(() {
        _selectedIndex = index;
      });
    }
  }

  /// navigation Tab widget for a list of all the screens and puts them in a Indexed Stack
  Widget _navigationTab(
      {GlobalKey<NavigatorState> navigationKey, Widget widget}) {
    return Navigator(
      key: navigationKey,
      onGenerateRoute: (routeSettings) {
        return MaterialPageRoute(builder: (context) => widget);
      },
    );
  }

  @override
  Widget build(BuildContext context) {
  
    return WillPopScope(
      onWillPop: () async {
        final isFirstRouteInCurrentTab =
            !await _items[_selectedIndex].navigationKey.currentState.maybePop();
        if (isFirstRouteInCurrentTab) {
          if (_selectedIndex != 0) {
            _onItemTapped(1);
            return false;
          }
        }

        /// let system handle back button if we're on the first route
        return isFirstRouteInCurrentTab;
      },
      child: Scaffold(
        body: IndexedStack(
          index: _selectedIndex,
          children: _items
              .map((e) => _navigationTab(
                  navigationKey: e.navigationKey, widget: e.widget))
              .toList(),
        ),
        bottomNavigationBar: BottomNavigationBar(
          items: <BottomNavigationBarItem>[
            BottomNavigationBarItem( 
              label: Screen1,
            ),
            BottomNavigationBarItem(
              label: Screen2,
            ),
            BottomNavigationBarItem(
              label: Screen3,
            ),
          ],
          currentIndex: _selectedIndex,
          showUnselectedLabels: true,
          onTap: _onItemTapped,
        ),
      ),
    );
  }
}

How is this achievable with this type of BNB? Thanks in advance for your help!