import 'package:flutter/material.dart';
void main() {
  runApp(
    new Center(
      child: new Text(
        'Hello, world!',
        textDirection: TextDirection.ltr,
      ),
    ),
  );
}

import 'package:flutter/material.dart';
void main() {
  runApp(new MaterialApp(
    title: 'Flutter Tutorial',
    home: new TutorialHome(),
  ));
}
class TutorialHome extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        leading: new IconButton(
          icon: new Icon(Icons.menu),
          tooltip: 'Navigation menu',
          onPressed: null,
        ),
        title: new Text('Example title'),
        actions: <Widget>[
          new IconButton(
            icon: new Icon(Icons.search),
            tooltip: 'Search',
            onPressed: null,
          ),
        ],
      ),
      body: new Center(
        child: new Text('Hello, world!'),
      ),
      floatingActionButton: new FloatingActionButton(
        tooltip: 'Add', // used by assistive technologies
        child: new Icon(Icons.add),
        onPressed: null,
      ),
    );
  }
}

class Product {
  const Product({this.name});
  final String name;
}
typedef void CartChangedCallback(Product product, bool inCart);
class ShoppingListItem extends StatelessWidget {
  ShoppingListItem({Product product, this.inCart, this.onCartChanged})
      : product = product,
        super(key: new ObjectKey(product));
  final Product product;
  final bool inCart;
  final CartChangedCallback onCartChanged;
  Color _getColor(BuildContext context) {
    return inCart ? Colors.black54 : Theme.of(context).primaryColor;
  }
  TextStyle _getTextStyle(BuildContext context) {
    if (!inCart) return null;
    return new TextStyle(
      color: Colors.black54,
      decoration: TextDecoration.lineThrough,
    );
  }
  @override
  Widget build(BuildContext context) {
    return new ListTile(
      onTap: () {
        onCartChanged(product, !inCart);
      },
      leading: new CircleAvatar(
        backgroundColor: _getColor(context),
        child: new Text(product.name[0]),
      ),
      title: new Text(product.name, style: _getTextStyle(context)),
    );
  }
}

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'),
        ],
      ),
    );
  //...
}