flutter - 如何在底部导航上方制作 flutter 抽屉

Question

我在 Flutter 项目中有一个简单的抽屉，我想让抽屉在用户滑动/打开时始终位于底部导航栏上方。我玩弄我的代码，但还找不到任何解决方案。

     import 'package:flutter/material.dart';
import 'package:testing2/pages/ChannelsPage.dart';
import 'package:testing2/pages/HomePage.dart';
import 'package:testing2/pages/ExplorePage.dart';
import 'package:testing2/fragments/first_fragment.dart';
import 'package:testing2/fragments/second_fragment.dart';
import 'package:testing2/fragments/third_fragment.dart';
import 'package:testing2/Shared/drawer.dart';

class MyHomePage extends StatefulWidget {

  @override
  _MyBottomNavigationBarState createState() => _MyBottomNavigationBarState();
}

class _MyBottomNavigationBarState extends State<MyHomePage> {
  final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>();
  int _currentSelected = 0;
  GlobalKey<ScaffoldState> _drawerKey = GlobalKey<ScaffoldState>();
  final List<Widget> _children = [
    HomePage(),
    SettingsPage(),
    ContactPage(),
    HomePage()
  ];

  void onTappedBar(int index){
    index == 3
    ? _drawerKey.currentState.openDrawer()
    : setState((){
      _currentSelected = index;
      
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      key: _drawerKey,
      drawer: new Drawer(
        child: ListView(
          children: <Widget>[
            new DrawerHeader(
              child: new Text('Jonathan'),
              decoration: new BoxDecoration(color: Colors.orange),),
              new ListTile(
                leading: const Icon(Icons.notifications),
                title: new Text('Notifications'),
                onTap: (){
                  Navigator.pop(context);
                  Navigator.push(context, new MaterialPageRoute(builder: (context) => new FirstFragment()));
                },
              ),
              new ListTile(
                leading: const Icon(Icons.list),
                title: new Text('Preferences'),
                onTap: (){
                  Navigator.pop(context);
                  Navigator.push(context, new MaterialPageRoute(builder: (context) => new SecondFragment()));
                },
              ),
              new ListTile(
                leading: const Icon(Icons.help),
                title: new Text('Help'),
                onTap: (){
                  Navigator.pop(context);
                  Navigator.push(context, new MaterialPageRoute(builder: (context) => new ThirdFragment()));
                },
              ),
              new ListTile(
                leading: const Icon(Icons.outlined_flag),
                title: new Text('Logout'),
                onTap: (){
                  Navigator.pop(context);
                  Navigator.push(context, new MaterialPageRoute(builder: (context) => new FirstFragment()));
                },
              ),
          ],
        )
      ),
      body:_children[_currentSelected],
      bottomNavigationBar: BottomNavigationBar(
        backgroundColor: Colors.blueGrey[900],  
        type: BottomNavigationBarType.fixed,
        onTap: onTappedBar,
        currentIndex: _currentSelected,
        showUnselectedLabels: true,
        unselectedItemColor: Colors.white,
        selectedItemColor: Color.fromRGBO(10, 135, 255, 1),
        items: <BottomNavigationBarItem> [ 
          BottomNavigationBarItem(icon: new Icon(Icons.home), title: new Text('Home')),
          BottomNavigationBarItem(icon: new Icon(Icons.search), title: new Text('Explore')),
          BottomNavigationBarItem(icon: new Icon(Icons.device_hub), title: new Text('Channels')),
          BottomNavigationBarItem(icon: new Icon(Icons.dehaze), title: new Text('More')),
        ],
      ),     
    );
  }
}
class Page extends StatelessWidget {
  const Page({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container();
  }
}

我按照你告诉我的方式做了，抽屉在底部导航栏的上方，但是打开抽屉的第四个图标不再工作了。

Answer 1

您可以通过以下方式执行此操作。

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  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: Business',
      style: optionStyle,
    ),
    Text(
      'Index 2: School',
      style: optionStyle,
    ),
  ];

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Scaffold(
        body: Center(
          child: _widgetOptions.elementAt(_selectedIndex),
        ),
        appBar: AppBar(
          title: Text("data"),
        ),
        drawer: Drawer(
          child: Center(
            child: RaisedButton(
              child: Text("Press"),
              onPressed: () {
                Navigator.push(
                    context, MaterialPageRoute(builder: (context) => Hello1()));
              },
            ),
          ),
        ),
      ),
      bottomNavigationBar: BottomNavigationBar(
        items: const <BottomNavigationBarItem>[
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            title: Text('Home'),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.business),
            title: Text('Business'),
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.school),
            title: Text('School'),
          ),
        ],
        currentIndex: _selectedIndex,
        selectedItemColor: Colors.amber[800],
        onTap: _onItemTapped,
      ),
    );
  }
}

class Hello1 extends StatelessWidget {
  const Hello1({Key key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        child: Center(
          child: Text("data"),
        ),
      ),
    );
  }
}