出处https://blog.csdn.net/z979451341/article/details/80693122
建议使用demo https://www.jianshu.com/p/9ab9d6d45cc0
超级牛逼的flutter完整项目代码 https://github.com/HappyGhostz
必须学好的flutter调用原生的demo https://www.jianshu.com/p/5e5d54db8c7e
高级flutter内容，编译原理与优化 https://yq.aliyun.com/articles/604052
/show_time_for_flutter

new Text('Hello World', style: new TextStyle(fontSize: 32.0))

new Image.asset('images/myPic.jpg', fit: BoxFit.cover)

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
 
    return new MaterialApp(
      title: 'Flutter base UI Widget',
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('Flutter base UI Widget'),
        ),
        body: new ListView(
          children: <Widget>[
            //add code
            new Text('Hello World', style: new TextStyle(fontSize: 32.0)),
            new Image.asset('images/lake.jpeg', width: 200.0,height: 200.0, fit: BoxFit.cover),
            new Icon(Icons.star, color: Colors.red[500])
 
 
 
          ],
        ),
      ),
    );
  }
  }

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
 
    Widget titleSection = new Container(
      padding: const EdgeInsets.all(32.0),
      child: new Row(
        children: [
          new Expanded(
            child: new Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                new Container(
                  padding: const EdgeInsets.only(bottom: 8.0),
                  child: new Text(
                    'Oeschinen Lake Campground',
                    style: new TextStyle(
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                ),
                new Text(
                  'Kandersteg, Switzerland',
                  style: new TextStyle(
                    color: Colors.grey[500],
                  ),
                ),
              ],
            ),
          ),
          new Icon(
            Icons.star,
            color: Colors.red[500],
          ),
          new Text('41'),
        ],
      ),
    );
 
    return new MaterialApp(
      title: 'Flutter base UI Widget',
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('Flutter base UI Widget'),
        ),
        body: new ListView(
          children: <Widget>[
            //add code
            titleSection
 
 
          ],
        ),
      ),
    );
  }
  }

    Widget titleSection = new Container(
      decoration: new BoxDecoration(
        border: new Border.all(width: 10.0, color: Colors.black38),
        borderRadius:
        const BorderRadius.all(const Radius.circular(8.0)),
 
      ),
      margin: const EdgeInsets.all(32.0),
      padding: const EdgeInsets.all(32.0),
      child: new Row(
 
        children: [
          new Expanded(
 
             // flex:1,
              child: new Text('one')),
          new Expanded(
            flex: 2,
              child: new Text('two')),
          new Expanded(
             // flex:1,
              child: new Text('three'))
        ],
      ),
    );

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}
 
class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
 
  final String title;
 
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}
 
// The images are saved with names pic1.jpg, pic2.jpg...pic30.jpg.
// The List.generate constructor allows an easy way to create
// a list when objects have a predictable naming pattern.
List<Container> _buildGridTileList(int count) {
  List<Container> containers = new List<Container>.generate(
      count,
          (int index) =>
      new Container(child: new Image.asset('images/lake.jpeg',width: 100.0,height: 100.0, fit: BoxFit.cover)));
  return containers;
}
 
Widget buildGrid() {
  return new GridView.extent(
      maxCrossAxisExtent: 150.0,
      padding: const EdgeInsets.all(4.0),
      mainAxisSpacing: 4.0,
      crossAxisSpacing: 4.0,
      children: _buildGridTileList(30));
}
 
class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(widget.title),
      ),
      body: new Center(
        child: buildGrid(),
      ),
    );
  }
}

    var stack = new Stack(
      alignment: const Alignment(0.6, 0.6),
      children: [
        new CircleAvatar(
          backgroundImage: new AssetImage('images/lake.jpeg'),
          radius: 100.0,
        ),
        new Container(
          decoration: new BoxDecoration(
            color: Colors.black45,
          ),
          child: new Text(
            'Mia B',
            style: new TextStyle(
              fontSize: 20.0,
              fontWeight: FontWeight.bold,
              color: Colors.white,
            ),
          ),
        ),
      ],
    );

    var card = new SizedBox(
      height: 95.0,
      child: new Card(
        margin: const EdgeInsets.all(10.0),
        elevation: 10.0,
        child: new Column(
          children: [
            new ListTile(
              title: new Text('1625 Main Street',
                  style: new TextStyle(fontWeight: FontWeight.w500)),
              subtitle: new Text('My City, CA 99984'),
              leading: new Icon(
                Icons.restaurant_menu,
                color: Colors.blue[500],
              ),
            )
          ],
        ),
      ),
    );