main.dart

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';

// This app is a stateful, it tracks the user's current choice.
class BasicAppBarSample extends StatefulWidget {
  @override
  _BasicAppBarSampleState createState() => _BasicAppBarSampleState();
}

class _BasicAppBarSampleState extends State<BasicAppBarSample> {
  Choice _selectedChoice = choices[0]; // The app's "state".

  void _select(Choice choice) {
    // Causes the app to rebuild with the new _selectedChoice.
    setState(() {
      _selectedChoice = choice;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Basic AppBar'),
          actions: <Widget>[
            // action button
            IconButton(
              icon: Icon(choices[0].icon),
              onPressed: () {
                _select(choices[0]);
              },
            ),
            // action button
            IconButton(
              icon: Icon(choices[1].icon),
              onPressed: () {
                _select(choices[1]);
              },
            ),
            // overflow menu
            PopupMenuButton<Choice>(
              onSelected: _select,
              itemBuilder: (BuildContext context) {
                return choices.skip(2).map((Choice choice) {
                  return PopupMenuItem<Choice>(
                    value: choice,
                    child: Text(choice.title),
                  );
                }).toList();
              },
            ),
          ],
        ),
        body: Padding(
          padding: const EdgeInsets.all(16.0),
          child: ChoiceCard(choice: _selectedChoice),
        ),
      ),
    );
  }
}

class Choice {
  const Choice({this.title, this.icon});

  final String title;
  final IconData icon;
}

const List<Choice> choices = const <Choice>[
  const Choice(title: 'Car', icon: Icons.directions_car),
  const Choice(title: 'Bicycle', icon: Icons.directions_bike),
  const Choice(title: 'Boat', icon: Icons.directions_boat),
  const Choice(title: 'Bus', icon: Icons.directions_bus),
  const Choice(title: 'Train', icon: Icons.directions_railway),
  const Choice(title: 'Walk', icon: Icons.directions_walk),
];


class GradientText extends StatelessWidget {
  GradientText(
    this.text, {
    @required this.gradient,
  });

  final String text;
  final Gradient gradient;

  @override
  Widget build(BuildContext context) {
    return ShaderMask(
      shaderCallback: (bounds) => gradient.createShader(
        Rect.fromLTWH(0, 0, bounds.width, bounds.height),
      ),
      child: Text(
        text,
        style: TextStyle(
          // The color must be set to white for this to work
          color: Colors.white,
          fontSize: 40,
        ),
      ),
    );
  }
}

class ChoiceCard extends StatelessWidget {
  const ChoiceCard({Key key, this.choice}) : super(key: key);

  final Choice choice;

  @override
  Widget build(BuildContext context) {
    final Shader linearGradient = LinearGradient(
  colors: <Color>[Color(0xff000000), Color(0xffffffff)],
).createShader(Rect.fromLTWH(0.0, 0.0, 200.0, 70.0));
    
    
    //final TextStyle textStyle = Theme.of(context).textTheme.headline4;
    final TextStyle textStyle = new TextStyle(
            fontSize: 60.0,
            fontWeight: FontWeight.bold,
            foreground: Paint()..shader = linearGradient);
    return Card(
      color: Colors.white,
      child: Container(decoration: BoxDecoration(
            gradient: LinearGradient(
              begin: Alignment.topRight,
              end: Alignment.bottomLeft,
              colors: [Colors.blue, Colors.red])),
                       child: Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Icon(choice.icon, size: 128.0, color: Colors.black),
            Text(choice.title, style: textStyle),
          ],
        ),
      )),
    );
  }
}

void main() {
  runApp(BasicAppBarSample());
}