NavigationBar影响页面的其余部分

Question

我正在为导航栏制作另一个文件。问题是当我尝试添加到我的主页时，因为我使用了Scaffold，它只是隐藏了我的主页中包含的所有内容。我如何修改NavigationBar的文件以使其正常工作（仅是一个小部件）并且不影响UI的其余部分。这是代码

import 'package:flutter/material.dart';
import 'google_nav_bar.dart';

class AppBarW extends StatefulWidget {
  @override
  _AppBarState createState() => _AppBarState();
}

class _AppBarState extends State<AppBarW> {
  int _selectedIndex = 0;
  static const TextStyle optionStyle =
      TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
  static const List<Widget> _widgetOptions = <Widget>[
    Text(
      'Index 0: Home',
      style: optionStyle,
    ),
    Text(
      'Index 1: Likes',
      style: optionStyle,
    ),
    Text(
      'Index 2: Search',
      style: optionStyle,
    ),
    Text(
      'Index 3: Profile',
      style: optionStyle,
    ),
  ];
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body:
    Container(
        padding: EdgeInsets.only(top: MediaQuery.of(context).size.height * 0.7),
        child: new BottomAppBar(
          child: Container(
            decoration: BoxDecoration(color: Colors.white, boxShadow: [
              BoxShadow(blurRadius: 20, color: Colors.black.withOpacity(.1))
            ]),
            child: SafeArea(
              child: Padding(
                padding:
                    const EdgeInsets.symmetric(horizontal: 15.0, vertical: 8),
                child: GNav(
                    gap: 8,
                    activeColor: Colors.white,
                    iconSize: 24,
                    padding: EdgeInsets.symmetric(horizontal: 20, vertical: 5),
                    duration: Duration(milliseconds: 800),
                    tabBackgroundColor: Colors.grey[800],
                    tabs: [
                      GButton(
                        icon: Icons.home,
                        text: 'Home',
                      ),
                      GButton(
                        icon: Icons.favorite,
                        text: 'Likes',
                      ),
                      GButton(
                        icon: Icons.search,
                        text: 'Search',
                      ),
                      GButton(
                        icon: Icons.person_pin_circle,
                        text: 'Profile',
                      ),
                    ],
                    selectedIndex: _selectedIndex,
                    onTabChange: (index) {
                      setState(() {
                        _selectedIndex = index;
                      });
                    }),
              ),
            ),
          ),
     ) ));
  }
}