weight_tracker flutter app

main.dart

import 'package:flutter/material.dart';
import 'dart:math';
import 'package:intl/intl.dart';

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

class MyApp extends StatelessWidget {
//  var _routes = <String, WidgetBuilder>{
//    AddContact.routeName: (BuildContext context) => new AddContact(title: 'Add Contact'),
//  };

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Weight Tracker',
      theme: ThemeData(
        primarySwatch: Colors.green,
      ),
      home: MyHomePage(title: 'Weight Tracker'),
//      routes: _routes,
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  List<WeightSave> weightSaves = new List();

  void _addWeightSave() {
    setState(() {
      weightSaves.add(new WeightSave(
          new DateTime.now(), new Random().nextInt(100).toDouble()));
    });
  }

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: new ListView(
        children: weightSaves.map((WeightSave weightSave) {
          //calculating difference
          double difference = weightSaves.first == weightSave
              ? 0.0
              : weightSave.weight -
                  weightSaves[weightSaves.indexOf(weightSave)].weight;
        }).toList(),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: () => _addWeightSave(),
        tooltip: 'Add new weight entry',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class WeightSave {
  DateTime dateTime;
  double weight;

  WeightSave(this.dateTime, this.weight);
}

class WeightListItem extends StatelessWidget {
  final WeightSave weightSave;
  final double weightDifference;

  WeightListItem(this.weightSave, this.weightDifference);

  @override
  Widget build(BuildContext context) {
    return new Padding(
      padding: new EdgeInsets.all(16.0),
      child: new Row(children: [
        new Expanded(
            child: new Column(children: [
              new Text(
                new DateFormat.yMMMMd().format(weightSave.dateTime),
                textScaleFactor: 0.9,
                textAlign: TextAlign.left,
              ),
              new Text(
                new DateFormat.EEEE().format(weightSave.dateTime),
                textScaleFactor: 0.8,
                textAlign: TextAlign.right,
                style: new TextStyle(
                  color: Colors.grey,
                ),
              ),
            ], crossAxisAlignment: CrossAxisAlignment.start)),
        new Expanded(
            child: new Text(
              weightSave.weight.toString(),
              textScaleFactor: 2.0,
              textAlign: TextAlign.center,
            )),
        new Expanded(
            child: new Text(
              weightDifference.toString(),
              textScaleFactor: 1.6,
              textAlign: TextAlign.right,
            )),
      ]),
    );
  }
}

pubspec.yaml

name: tutorial
description: A new Flutter project.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+1

environment:
  sdk: ">=2.0.0-dev.68.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2
  intl: ^0.15.7

dev_dependencies:
  flutter_test:
    sdk: flutter


# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.io/assets-and-images/#resolution-aware.

  # For details regarding adding assets from package dependencies, see
  # https://flutter.io/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.io/custom-fonts/#from-packages