Flutter Widget Code

bottomnavigationbar.dart

class Nav extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _TestState();
  }
}

class _NavState extends State<Nav> {
  int _count = 0;

  int _selectIndex = 0;
  final _options = [
    Text('AA'),
    Text('BB'),
    Text('CC'),
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Test'),
      ),
      body: Center(child: _options[_selectIndex]),
      bottomNavigationBar: BottomNavigationBar(
        items: <BottomNavigationBarItem>[
          BottomNavigationBarItem(icon: Icon(Icons.chat), title: Text('A')),
          BottomNavigationBarItem(icon: Icon(Icons.headset), title: Text('B')),
          BottomNavigationBarItem(icon: Icon(Icons.settings), title: Text('C')),
        ],
        currentIndex: _selectIndex,
        fixedColor: Colors.cyan,
        onTap: (int index) {
          setState(() {
            _selectIndex = index;
          });
        },
      ),
    );
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Nav(),
    );
  }
}

Column.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      title: 'Fultter',
      home: Scaffold(
        appBar: new AppBar(
          title: new Text('Title'),
        ),
        body: Center(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Text('aaa'),
              Text('basdasdbb'),
              Text('ccc')
            ],
          )
        )
      )
    );
  }
}

dynamic-ListView.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp(
  items: new List<String>.generate(1000, (i) => "Item $i")
));

class MyApp extends StatelessWidget {
  final List<String> items;

  MyApp({Key key, @required this.items}): super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: new AppBar(title: new Text('Title')),
        body: new ListView.builder(
          itemCount: items.length,
          itemBuilder: (context, index){
            return new ListTile(
              title: new Text('${items[index]}')
            );
          },
        )
      )
    );
  }
}

GridView.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: new AppBar(title: new Text('Title')),
        body: GridView(
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: 3,
            mainAxisSpacing: 4,
            crossAxisSpacing: 4,
            childAspectRatio: 0.7
          ),
          children: <Widget>[
            new Image.network('https://images.unsplash.com/photo-1542841791-c3cc44abdbbb?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=934&q=80'),
            new Image.network('https://images.unsplash.com/photo-1542841366-ddfe55c504a3?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1510520434124-5bc7e642b61d?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1502898295-455afaf0f015?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1509503643053-8fc818177382?ixlib=rb-1.2.1&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1433954558247-ba7696b9af19?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1512477815698-9ba49ad36d22?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1440589473619-3cde28941638?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60'),
            new Image.network('https://images.unsplash.com/photo-1494790108377-be9c29b29330?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=800&q=60')
          ],
        )
      )
    );
  }
}

navigator.dart

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',
      home: new MyHomePage(),
      routes: <String, WidgetBuilder>{
        '/settings': (BuildContext context) => new SettingsPage(),
      },
    );
  }
}

class MyHomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          title: new Text('TestProject'),
        ),
        body: new Center(
            child: new FlatButton(
                child: const Text('Go to Settings'),
                onPressed: () => Navigator.of(context).pushNamed('/settings')
            )
        )
    );
  }
}

class SettingsPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
        appBar: new AppBar(
          title: new Text('SettingsPage'),
        ),
        body: new Center(
            child: new Text('Settings')
        )
    );
  }
}

row.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // TODO: implement build
    return MaterialApp(
      title: 'Fultter',
      home: Scaffold(
        appBar: new AppBar(
          title: new Text('Title'),
        ),
        body: new Row(
          children: <Widget>[
            Expanded(
              child: new RaisedButton(
                onPressed: (){},
                color: Colors.blue,
                textColor: Colors.white,
                child: new Text('1button'),
              )
            ),
            Expanded(
                child: new RaisedButton(
                  onPressed: (){},
                  color: Colors.blue,
                  textColor: Colors.white,
                  child: new Text('2button'),
                )
            ),
            new RaisedButton(
              onPressed: (){},
              color: Colors.blue,
              textColor: Colors.white,
              child: new Text('bbbbutton'),
            )
          ],
        )
      )
    );
  }
}

Stack.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // 抽组件
    var stack = new Stack(
      alignment: const FractionalOffset(0.5, 0.5),
      children: <Widget>[
        new CircleAvatar(
          backgroundImage: new NetworkImage('https://images.unsplash.com/photo-1542841791-c3cc44abdbbb?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=934&q=80'),
          radius: 100,
        ),
        new Container(
          decoration: new BoxDecoration(
            color: Colors.blue,
          ),
          padding: EdgeInsets.all(5),
          child: Text('riskers'),
        )
      ],  
    );
    
    return MaterialApp(
      title: 'Fultter',
      home: Scaffold(
        appBar: new AppBar(
          title: new Text('Title'),
        ),
        body: Center(
          child: stack
        )
      )
    );
  }
}

static-ListView.dart

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter',
      home: Scaffold(
        appBar: new AppBar(title: new Text('Title')),
        body: new ListView(
          children: <Widget>[
            new ListTile(
              leading: new Icon(Icons.access_time),
              title: new Text('abc'),
            ),
            new ListTile(
              leading: new Icon(Icons.access_alarms),
              title: new Text('abc'),
            ),
            new ListTile(
              leading: new Icon(Icons.access_time),
              title: new Text('abc'),
            ),
          ],
        )
      )
    );
  }
}