import 'package:flutter/material.dart';
import 'package:english_words/english_words.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: 'Startup Name Generator',
        home: RandomWords(),
    );
  }
}

class RandomWordsState extends State<RandomWords> {
  final _suggestions = <WordPair>[];
  final _biggerFont = const TextStyle(fontSize: 18.0);

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Startup Name Generator'),
      ),
      body: _buildSuggestions(),
    );
  }

  Widget _buildSuggestions() {
    return ListView.builder(
        padding: const EdgeInsets.all(16.0),
        itemBuilder: /*1*/ (context, i) {
          if (i.isOdd) return Divider(); /*2*/

          final index = i ~/ 2; /*3*/
          if (index >= _suggestions.length) {
            _suggestions.addAll(generateWordPairs().take(10)); /*4*/
          }
          return _buildRow(_suggestions[index]);
        });
  }
  Widget _buildRow(WordPair pair) {
    return ListTile(
      title: Text(
        pair.asPascalCase,
        style: _biggerFont,
      ),
    );
  }
}

class RandomWords extends StatefulWidget {
  @override
  RandomWordsState createState() => RandomWordsState();
}

import 'package:flutter/material.dart';

void main() => runApp(MaterialApp(
  home: Home()
));

class Home extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('my first app'),
        centerTitle: true,
        backgroundColor: Colors.red[600],
      ),
      body: Center(
        child: Text(
          'hello ninjas!',
          style: TextStyle(
              fontSize: 20.0,
              fontWeight: FontWeight.bold,
              letterSpacing: 2.0,
              color: Colors.grey[600],
              fontFamily: 'IndieFlower'
          ),
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {},
        child: Text('click'),
        backgroundColor: Colors.red[600],
      ),
    );
  }
}

import 'dart:math';

void main() {
  final square = Square(side: 10.0);
  printArea(square);
  final circle = Circle(radius: 5.0);
  printArea(circle);
}

void printArea(Shape shape) {
  print(shape.area);
}

abstract class Shape {
  double get area;
}

class Square implements Shape {
  Square({this.side});
  final double side;
  double get area => side * side;
}

class Circle implements Shape {
  Circle({this.radius});
  final double radius;
  double get area => radius * radius * pi;
}

void main() {
  final employee = Employee(name: 'Andrea', age: 34, height: 1.84, taxCode: 'AB12', salary: 50000);
  employee.sayName();
  print(employee);
}

class Person {
  Person({this.name, this.age, this.height});
  String name;
  int age;
  double height;

  @override
  String toString() => 'name: $name, age: $age, height: $height';
  String describe() =>
      "Hello, I'm $name. I'm $age years old, I'm $height metters tall";

  void sayName() => print("Hello, I'm $name");
}

class Employee extends Person {
  Employee({String name,int age, double height, this.taxCode, this.salary})
    : super(name: name, age: age, height: height);
  final String taxCode;
  final int salary;
  @override
  String toString() => "${super.toString()}, taxCode: $taxCode, salary: $salary";
}

const Scaffold({
Key key,
PreferredSizeWidget appBar,   //
Widget body,    //
Widget floatingActionButton,    //
FloatingActionButtonLocation floatingActionButtonLocation,//
FloatingActionButtonAnimator floatingActionButtonAnimator,//
List<Widget> persistentFooterButtons,//
Widget drawer,  //
Widget endDrawer,  //
Widget bottomNavigationBar,
Widget bottomSheet,
Color backgroundColor,
bool resizeToAvoidBottomPadding,
bool resizeToAvoidBottomInset,
bool primary: true,
DragStartBehavior drawerDragStartBehavior: DragStartBehavior.start,
bool extendBody: false,
Color drawerScrimColor
})

class $1 extends StatefulWidget {
  const $1();
  @override
  _$2 createState() => _$2();
}

class $2 extends State<$1> {

  const $2();

  Widget build(BuildContext context) {
      return Padding(
                   padding: EdgeInsets.only(top: 16.0),
                   child: OrientationBuilder(
                     builder: (BuildContext context, Orientation orientation) {
                       if (orientation == Orientation.portrait) {
                         return OrientationPortrait();
                       } else {
                         return OrientationLandscape();
                       }
                     },
                   ),
                 );
  }
}

import 'package:flutter/material.dart';
import 'package:meta/meta.dart';

import 'category.dart';
import 'unit.dart';

const _padding = EdgeInsets.all(16.0);

class UnitConverter extends StatefulWidget {
  final Category category;

  const UnitConverter({
    @required this.category,
  }) : assert(category != null);

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

class _UnitConverterState extends State<UnitConverter> {
  Unit _fromValue;
  Unit _toValue;
  double _inputValue;
  String _convertedValue = '';
  List<DropdownMenuItem> _unitMenuItems;
  bool _showValidationError = false;
  final _inputKey = GlobalKey(debugLabel: 'inputText');

  @override
  void initState() {
    super.initState();
    _createDropdownMenuItems();
    _setDefaults();
  }

  @override
  void didUpdateWidget(UnitConverter old) {
    super.didUpdateWidget(old);
    if (old.category != widget.category) {
      _createDropdownMenuItems();
      _setDefaults();
    }
  }

  void _createDropdownMenuItems() {
    var newItems = <DropdownMenuItem>[];
    for (var unit in widget.category.units) {
      newItems.add(DropdownMenuItem(
        value: unit.name,
        child: Container(
          child: Text(
            unit.name,
            softWrap: true,
          ),
        ),
      ));
    }
    setState(() {
      _unitMenuItems = newItems;
    });
  }

  void _setDefaults() {
    setState(() {
      _fromValue = widget.category.units[0];
      _toValue = widget.category.units[1];
    });
    if (_inputValue != null) {
      _updateConversion();
    }
  }

  String _format(double conversion) {
    var outputNum = conversion.toStringAsPrecision(7);
    if (outputNum.contains('.') && outputNum.endsWith('0')) {
      var i = outputNum.length - 1;
      while (outputNum[i] == '0') {
        i -= 1;
      }
      outputNum = outputNum.substring(0, i + 1);
    }
    if (outputNum.endsWith('.')) {
      return outputNum.substring(0, outputNum.length - 1);
    }
    return outputNum;
  }

  void _updateConversion() {
    setState(() {
      _convertedValue =
          _format(_inputValue * (_toValue.conversion / _fromValue.conversion));
    });
  }

  void _updateInputValue(String input) {
    setState(() {
      if (input == null || input.isEmpty) {
        _convertedValue = '';
      } else {
        try {
          final inputDouble = double.parse(input);
          _showValidationError = false;
          _inputValue = inputDouble;
          _updateConversion();
        } on Exception catch (e) {
          print('Error: $e');
          _showValidationError = true;
        }
      }
    });
  }

  Unit _getUnit(String unitName) {
    return widget.category.units.firstWhere(
      (Unit unit) {
        return unit.name == unitName;
      },
      orElse: null,
    );
  }

  void _updateFromConversion(dynamic unitName) {
    setState(() {
      _fromValue = _getUnit(unitName);
    });
    if (_inputValue != null) {
      _updateConversion();
    }
  }

  void _updateToConversion(dynamic unitName) {
    setState(() {
      _toValue = _getUnit(unitName);
    });
    if (_inputValue != null) {
      _updateConversion();
    }
  }

  Widget _createDropdown(String currentValue, ValueChanged<dynamic> onChanged) {
    return Container(
      margin: EdgeInsets.only(top: 16.0),
      decoration: BoxDecoration(
        // This sets the color of the [DropdownButton] itself
        color: Colors.grey[50],
        border: Border.all(
          color: Colors.grey[400],
          width: 1.0,
        ),
      ),
      padding: EdgeInsets.symmetric(vertical: 8.0),
      child: Theme(
        // This sets the color of the [DropdownMenuItem]
        data: Theme.of(context).copyWith(
              canvasColor: Colors.grey[50],
            ),
        child: DropdownButtonHideUnderline(
          child: ButtonTheme(
            alignedDropdown: true,
            child: DropdownButton(
              value: currentValue,
              items: _unitMenuItems,
              onChanged: onChanged,
              style: Theme.of(context).textTheme.title,
            ),
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final input = Padding(
      padding: _padding,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          TextField(
            key: _inputKey,
            style: Theme.of(context).textTheme.display1,
            decoration: InputDecoration(
              labelStyle: Theme.of(context).textTheme.display1,
              errorText: _showValidationError ? 'Invalid number entered' : null,
              labelText: 'Input',
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(0.0),
              ),
            ),
            keyboardType: TextInputType.number,
            onChanged: _updateInputValue,
          ),
          _createDropdown(_fromValue.name, _updateFromConversion),
        ],
      ),
    );

    final arrows = RotatedBox(
      quarterTurns: 1,
      child: Icon(
        Icons.compare_arrows,
        size: 40.0,
      ),
    );

    final output = Padding(
      padding: _padding,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          InputDecorator(
            child: Text(
              _convertedValue,
              style: Theme.of(context).textTheme.display1,
            ),
            decoration: InputDecoration(
              labelText: 'Output',
              labelStyle: Theme.of(context).textTheme.display1,
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(0.0),
              ),
            ),
          ),
          _createDropdown(_toValue.name, _updateToConversion),
        ],
      ),
    );

    final converter = ListView(
      children: [
        input,
        arrows,
        output,
      ],
    );

    return Padding(
      padding: _padding,
      child: OrientationBuilder(
        builder: (BuildContext context, Orientation orientation) {
          if (orientation == Orientation.portrait) {
            return converter;
          } else {
            return Center(
              child: Container(
                width: 450.0,
                child: converter,
              ),
            );
          }
        },
      ),
    );
  }
}

class $1 extends StatefulWidget {
  const $1();
  @override
  _$2 createState() => _$2();
}

class $2 extends State<$1> {
  const $2();

  Widget _buildMyWidgets(Orientation deviceOrientation) {
    if (deviceOrientation == Orientation.portrait) {
          return OrientationPortrait();
        } else {
          return OrientationLandscape();
        }
  }

  Widget build(BuildContext context) {
      return _buildMyWidgets(MediaQuery.of(context).orientation);
  }
}

import 'package:flutter/material.dart';

import 'backdrop.dart';
import 'category.dart';
import 'category_tile.dart';
import 'unit.dart';
import 'unit_converter.dart';
class CategoryRoute extends StatefulWidget {
  const CategoryRoute();

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

class _CategoryRouteState extends State<CategoryRoute> {
  Category _defaultCategory;
  Category _currentCategory;
  final _categories = <Category>[];
  static const _categoryNames = <String>[
    'Length',
    'Area',
    'Volume',
    'Mass',
    'Time',
    'Digital Storage',
    'Energy',
    'Currency',
  ];
  static const _baseColors = <ColorSwatch>[
    ColorSwatch(0xFF6AB7A8, {
      'highlight': Color(0xFF6AB7A8),
      'splash': Color(0xFF0ABC9B),
    }),
    ColorSwatch(0xFFFFD28E, {
      'highlight': Color(0xFFFFD28E),
      'splash': Color(0xFFFFA41C),
    }),
    ColorSwatch(0xFFFFB7DE, {
      'highlight': Color(0xFFFFB7DE),
      'splash': Color(0xFFF94CBF),
    }),
    ColorSwatch(0xFF8899A8, {
      'highlight': Color(0xFF8899A8),
      'splash': Color(0xFFA9CAE8),
    }),
    ColorSwatch(0xFFEAD37E, {
      'highlight': Color(0xFFEAD37E),
      'splash': Color(0xFFFFE070),
    }),
    ColorSwatch(0xFF81A56F, {
      'highlight': Color(0xFF81A56F),
      'splash': Color(0xFF7CC159),
    }),
    ColorSwatch(0xFFD7C0E2, {
      'highlight': Color(0xFFD7C0E2),
      'splash': Color(0xFFCA90E5),
    }),
    ColorSwatch(0xFFCE9A9A, {
      'highlight': Color(0xFFCE9A9A),
      'splash': Color(0xFFF94D56),
      'error': Color(0xFF912D2D),
    }),
  ];

  @override
  void initState() {
    super.initState();
    for (var i = 0; i < _categoryNames.length; i++) {
      var category = Category(
        name: _categoryNames[i],
        color: _baseColors[i],
        iconLocation: Icons.cake,
        units: _retrieveUnitList(_categoryNames[i]),
      );
      if (i == 0) {
        _defaultCategory = category;
      }
      _categories.add(category);
    }
  }

  void _onCategoryTap(Category category) {
    setState(() {
      _currentCategory = category;
    });
  }

  Widget _buildCategoryWidgets(Orientation deviceOrientation) {
    if (deviceOrientation == Orientation.portrait) {
      return ListView.builder(
        itemBuilder: (BuildContext context, int index) {
          return CategoryTile(
            category: _categories[index],
            onTap: _onCategoryTap,
          );
        },
        itemCount: _categories.length,
      );
    } else {
      return GridView.count(
        crossAxisCount: 2,
        childAspectRatio: 3.0,
        children: _categories.map((Category c) {
          return CategoryTile(
            category: c,
            onTap: _onCategoryTap,
          );
        }).toList(),
      );
    }
  }

  List<Unit> _retrieveUnitList(String categoryName) {
    return List.generate(10, (int i) {
      i += 1;
      return Unit(
        name: '$categoryName Unit $i',
        conversion: i.toDouble(),
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    assert(debugCheckHasMediaQuery(context));
    final listView = Padding(
      padding: EdgeInsets.only(
        left: 8.0,
        right: 8.0,
        bottom: 48.0,
      ),
      child: _buildCategoryWidgets(MediaQuery.of(context).orientation),
    );

    return Backdrop(
      currentCategory:
          _currentCategory == null ? _defaultCategory : _currentCategory,
      frontPanel: _currentCategory == null
          ? UnitConverter(category: _defaultCategory)
          : UnitConverter(category: _currentCategory),
      backPanel: listView,
      frontTitle: Text('Unit Converter'),
      backTitle: Text('Select a Category'),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:meta/meta.dart';
import 'unit.dart';

const _padding = EdgeInsets.all(16.0);
class ConverterRoute extends StatefulWidget {
  final String name;

  final Color color;

  final List<Unit> units;

  const ConverterRoute({
    @required this.name,
    @required this.color,
    @required this.units,
  })  : assert(name != null),
        assert(color != null),
        assert(units != null);

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

class _ConverterRouteState extends State<ConverterRoute> {
  Unit _fromValue;
  Unit _toValue;
  double _inputValue;
  String _convertedValue = '';
  List<DropdownMenuItem> _unitMenuItems;
  bool _showValidationError = false;

  @override
  void initState() {
    super.initState();
    _createDropdownMenuItems();
    _setDefaults();
  }

  void _createDropdownMenuItems() {
    var newItems = <DropdownMenuItem>[];
    for (var unit in widget.units) {
      newItems.add(DropdownMenuItem(
        value: unit.name,
        child: Container(
          child: Text(
            unit.name,
            softWrap: true,
          ),
        ),
      ));
    }
    setState(() {
      _unitMenuItems = newItems;
    });
  }

  void _setDefaults() {
    setState(() {
      _fromValue = widget.units[0];
      _toValue = widget.units[1];
    });
  }

  String _format(double conversion) {
    var outputNum = conversion.toStringAsPrecision(7);
    if (outputNum.contains('.') && outputNum.endsWith('0')) {
      var i = outputNum.length - 1;
      while (outputNum[i] == '0') {
        i -= 1;
      }
      outputNum = outputNum.substring(0, i + 1);
    }
    if (outputNum.endsWith('.')) {
      return outputNum.substring(0, outputNum.length - 1);
    }
    return outputNum;
  }

  void _updateConversion() {
    setState(() {
      _convertedValue =
          _format(_inputValue * (_toValue.conversion / _fromValue.conversion));
    });
  }

  void _updateInputValue(String input) {
    setState(() {
      if (input == null || input.isEmpty) {
        _convertedValue = '';
      } else {
        try {
          final inputDouble = double.parse(input);
          _showValidationError = false;
          _inputValue = inputDouble;
          _updateConversion();
        } on Exception catch (e) {
          print('Error: $e');
          _showValidationError = true;
        }
      }
    });
  }

  Unit _getUnit(String unitName) {
    return widget.units.firstWhere(
      (Unit unit) {
        return unit.name == unitName;
      },
      orElse: null,
    );
  }

  void _updateFromConversion(dynamic unitName) {
    setState(() {
      _fromValue = _getUnit(unitName);
    });
    if (_inputValue != null) {
      _updateConversion();
    }
  }

  void _updateToConversion(dynamic unitName) {
    setState(() {
      _toValue = _getUnit(unitName);
    });
    if (_inputValue != null) {
      _updateConversion();
    }
  }

  Widget _createDropdown(String currentValue, ValueChanged<dynamic> onChanged) {
    return Container(
      margin: EdgeInsets.only(top: 16.0),
      decoration: BoxDecoration(
        color: Colors.grey[50],
        border: Border.all(
          color: Colors.grey[400],
          width: 1.0,
        ),
      ),
      padding: EdgeInsets.symmetric(vertical: 8.0),
      child: Theme(
        data: Theme.of(context).copyWith(
              canvasColor: Colors.grey[50],
            ),
        child: DropdownButtonHideUnderline(
          child: ButtonTheme(
            alignedDropdown: true,
            child: DropdownButton(
              value: currentValue,
              items: _unitMenuItems,
              onChanged: onChanged,
              style: Theme.of(context).textTheme.title,
            ),
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final input = Padding(
      padding: _padding,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          TextField(
            style: Theme.of(context).textTheme.display1,
            decoration: InputDecoration(
              labelStyle: Theme.of(context).textTheme.display1,
              errorText: _showValidationError ? 'Invalid number entered' : null,
              labelText: 'Input',
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(0.0),
              ),
            ),
            keyboardType: TextInputType.number,
            onChanged: _updateInputValue,
          ),
          _createDropdown(_fromValue.name, _updateFromConversion),
        ],
      ),
    );

    final arrows = RotatedBox(
      quarterTurns: 1,
      child: Icon(
        Icons.compare_arrows,
        size: 40.0,
      ),
    );

    final output = Padding(
      padding: _padding,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          InputDecorator(
            child: Text(
              _convertedValue,
              style: Theme.of(context).textTheme.display1,
            ),
            decoration: InputDecoration(
              labelText: 'Output',
              labelStyle: Theme.of(context).textTheme.display1,
              border: OutlineInputBorder(
                borderRadius: BorderRadius.circular(0.0),
              ),
            ),
          ),
          _createDropdown(_toValue.name, _updateToConversion),
        ],
      ),
    );

    final converter = Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        input,
        arrows,
        output,
      ],
    );

    return Padding(
      padding: _padding,
      child: converter,
    );
  }
}

class $1 extends StatefulWidget {
  const $1();
  @override
  _$2 createState() => _$2();
}

class $2 extends State<$1> {

  const $2();

  @override
  void initState() {
    super.initState();
  }

  void _updateInputValue(String input) {
    setState(() {

    });
  }

  Widget build(BuildContext context) {
      return Container(
                  onChanged: _updateInputValue,
                 );
  }
}

class CategoryRoute extends StatefulWidget {
  const CategoryRoute();

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

class _CategoryRouteState extends State<CategoryRoute> {
  final _categories = <Category>[];

  static const _categoryNames = <String>[
    'Length',
    'Area',
    'Volume',
    'Mass',
    'Time',
    'Digital Storage',
    'Energy',
    'Currency',
  ];

  static const _baseColors = <Color>[
    Colors.teal,
    Colors.orange,
    Colors.pinkAccent,
    Colors.blueAccent,
    Colors.yellow,
    Colors.greenAccent,
    Colors.purpleAccent,
    Colors.red,
  ];

  @override
  void initState() {
    super.initState();
    for (var i = 0; i < _categoryNames.length; i++) {
      _categories.add(Category(
        name: _categoryNames[i],
        color: _baseColors[i],
        iconLocation: Icons.cake,
        units: _retrieveUnitList(_categoryNames[i]),
      ));
    }
  }

  Widget _buildCategoryWidgets() {
    return ListView.builder(
      itemBuilder: (BuildContext context, int index) => _categories[index],
      itemCount: _categories.length,
    );
  }

  List<Unit> _retrieveUnitList(String categoryName) {
    return List.generate(10, (int i) {
      i += 1;
      return Unit(
        name: '$categoryName Unit $i',
        conversion: i.toDouble(),
      );
    });
  }

  @override
  Widget build(BuildContext context) {
    final listView = Container(
      color: _backgroundColor,
      padding: EdgeInsets.symmetric(horizontal: 8.0),
      child: _buildCategoryWidgets(),
    );

    final appBar = AppBar(
      elevation: 0.0,
      title: Text(
        'Unit Converter',
        style: TextStyle(
          color: Colors.black,
          fontSize: 30.0,
        ),
      ),
      centerTitle: true,
      backgroundColor: _backgroundColor,
    );

    return Scaffold(
      appBar: appBar,
      body: listView,
    );
  }
}

class $2 extends State<$1> {
  final p1 = <T1>[];
  
  const $2();
  static const _listValues1 = <String>[
    'v1',
    'v2',
    'v3',
  ];
  
  @override
  void initState() {
    super.initState();
    for (var i = 0; i < _listValues1.length; i++) {
      p1.add(T1(value: _listValues1[i]));
    }
  }
  
  _buildP1Widgets(List<Widget> p1) {
    return ListView.builder(
          itemBuilder: (BuildContext context, int index) => p1[index],
          itemCount: p1.length,
        );
  }
  
  Widget build(BuildContext context) {
      return Container(
                  padding: EdgeInsets.symmetric(horizontal: 8.0),
                  child: _buildP1Widgets(p1),
                 );
  }
}

class T1 extends StatelessWidget {
  final T1 v1;
  
  const $1({
    Key key,
    @required this.v1,
  }) : assert( v1 != null ),
       super(key: key);
  
  @override
  Widget build(BuildContext context) {
    return Widget();
  }
}

import 'package:flutter/material.dart';
import 'package:meta/meta.dart';
import 'converter_route.dart';
import 'unit.dart';
final _rowHeight = 100.0;
final _borderRadius = BorderRadius.circular(_rowHeight / 2);

class Category extends StatelessWidget {
  final String name;
  final ColorSwatch color;
  final IconData iconLocation;
  final List<Unit> units;

  const Category({
    Key key,
    @required this.name,
    @required this.color,
    @required this.iconLocation,
    @required this.units,
  })  : assert(name != null),
        assert(color != null),
        assert(iconLocation != null),
        assert(units != null),
        super(key: key);

  void _navigateToConverter(BuildContext context) {
    Navigator.of(context).push(MaterialPageRoute<Null>(
      builder: (BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            elevation: 1.0,
            title: Text(
              name,
              style: Theme.of(context).textTheme.display1,
            ),
            centerTitle: true,
            backgroundColor: color,
          ),
          body: ConverterRoute(
            color: color,
            name: name,
            units: units,
          ),
        );
      },
    ));
  }

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.transparent,
      child: Container(
        height: _rowHeight,
        child: InkWell(
          borderRadius: _borderRadius,
          highlightColor: color,
          splashColor: color,
          onTap: () => _navigateToConverter(context),
          child: Padding(
            padding: EdgeInsets.all(8.0),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Padding(
                  padding: EdgeInsets.all(16.0),
                  child: Icon(
                    iconLocation,
                    size: 60.0,
                  ),
                ),
                Center(
                  child: Text(
                    name,
                    textAlign: TextAlign.center,
                    style: Theme.of(context).textTheme.headline,
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

class T1 extends StatelessWidget {
  final T1 v1;
  
  const $1({
    Key key,
    @required this.v1,
  }) : assert( v1 != null ),
       super(key: key);
  
  void _navigateToWidget(BuildContext context) {
    Navigator.of(context).push(MaterialPageRoute<Null>(
       builder: (BuildContext context) {
         return Scaffold(
           appBar: Widget(),
           body: Widget(),
         );
         },
     ));
  }
  
  @override
  Widget build(BuildContext context) {
    return Widget(
        onTap: () => _navigateToWidget(context),
    );
  }
}

class T1 extends StatelessWidget {
  final T1 v1;
  
  const $1({
    Key key,
    @required this.v1,
  }) : assert( v1 != null ),
       super(key: key);
  
  @override
  Widget build(BuildContext context) {
    return Widget();
  }
}

class CategoryRoute extends StatelessWidget {
  const CategoryRoute();

  static const _categoryNames = <String>[
    'Length',
    'Area',
    'Volume',
    'Mass',
    'Time',
    'Digital Storage',
    'Energy',
    'Currency',
  ];

  static const _baseColors = <Color>[
    Colors.teal,
    Colors.orange,
    Colors.pinkAccent,
    Colors.blueAccent,
    Colors.yellow,
    Colors.greenAccent,
    Colors.purpleAccent,
    Colors.red,
  ];

  /// Makes the correct number of rows for the list view.
  ///
  /// For portrait, we construct a [ListView] from the list of category widgets.
  Widget _buildCategoryWidgets(List<Widget> categories) {
    return ListView.builder(
      itemBuilder: (BuildContext context, int index) => categories[index],
      itemCount: categories.length,
    );
  }

  @override
  Widget build(BuildContext context) {
    final categories = <Category>[];

    for (var i = 0; i < _categoryNames.length; i++) {
      categories.add(Category(
        name: _categoryNames[i],
        color: _baseColors[i],
        iconLocation: Icons.cake,
      ));
    }

    final listView = Container(
      color: _backgroundColor,
      padding: EdgeInsets.symmetric(horizontal: 8.0),
      child: _buildCategoryWidgets(categories),
    );

    final appBar = AppBar(
      elevation: 0.0,
      title: Text(
        'Unit Converter',
        style: TextStyle(
          color: Colors.black,
          fontSize: 30.0,
        ),
      ),
      centerTitle: true,
      backgroundColor: _backgroundColor,
    );

    return Scaffold(
      appBar: appBar,
      body: listView,
    );
  }
 }

class $1 extends StatelessWidget {
  const $1();
  static const _listValues1 = <String>[
    'v1',
    'v2',
    'v3',
  ];
  
  _buildP1Widgets(List<Widget> p1) {
    return ListView.builder(
          itemBuilder: (BuildContext context, int index) => p1[index],
          itemCount: p1.length,
        );
  }
  
  Widget build(BuildContext context) {
      final p1 = <T1>[];
  
      for (var i = 0; i < _listValues1.length; i++) {
        p1.add(T1(value: _listValues1[i]));
      }
      
      return Container(
                  padding: EdgeInsets.symmetric(horizontal: 8.0),
                  child: _buildP1Widgets(p1),
                 );
  }
}