dart实例

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new ScaffoldRoute(),
    );
  }
}

class ScaffoldRoute extends StatefulWidget {
  @override
  _ScaffoldRouteState createState() => _ScaffoldRouteState();
}

class _ScaffoldRouteState extends State<ScaffoldRoute> {
  int _selectedIndex = ;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar( //导航栏
        title: Text("App Name"),
        actions: <Widget>[ //导航栏右侧菜单
          IconButton(icon: Icon(Icons.share), onPressed: () {}),
        ],
      ),
      drawer: new MyDrawer(), //抽屉
        bottomNavigationBar: BottomAppBar(
          color: Colors.white,
          shape: CircularNotchedRectangle(), // 底部导航栏打一个圆形的洞
          child: Row(
            children: [
              IconButton(icon: Icon(Icons.home)),
              SizedBox(), //中间位置空出
              IconButton(icon: Icon(Icons.business)),
            ],
            mainAxisAlignment: MainAxisAlignment.spaceAround, //均分底部导航栏横向空间
          ),
        )
      /*
        bottomNavigationBar: BottomNavigationBar( // 底部导航
        items: <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,
        fixedColor: Colors.blue,
        onTap: _onItemTapped,
      ),
      */
       // floatingActionButton: FloatingActionButton( //悬浮按钮
      //    child: Icon(Icons.add),
      //    onPressed:_onAdd
      //),

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

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

  @override
  Widget build(BuildContext context) {
    return Drawer(
      child: MediaQuery.removePadding(
        context: context,
        // DrawerHeader consumes top MediaQuery padding.
        removeTop: true,
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: <Widget>[
            Padding(
              padding: const EdgeInsets.only(top: 38.0),
              child: Row(
                children: <Widget>[
                  Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 16.0),
                    child: ClipOval(
                      child: Image.asset(
                        "imgs/avatar.png",
                        width: ,
                      ),
                    ),
                  ),
                  Text(
                    "Wendux",
                    style: TextStyle(fontWeight: FontWeight.bold),
                  )
                ],
              ),
            ),
            Expanded(
              child: ListView(
                children: <Widget>[
                  ListTile(
                    leading: const Icon(Icons.add),
                    title: const Text('Add account'),
                  ),
                  ListTile(
                    leading: const Icon(Icons.settings),
                    title: const Text('Manage accounts'),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}