cpd_2022_energy/lib/main.dart

import 'package:energy/model/EnergyModelProvider.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

void main() {
  runApp(const EnergyProviderApp());
}

class EnergyProviderApp extends StatelessWidget {
  const EnergyProviderApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Energy App',
      theme: ThemeData(
        primarySwatch: Colors.yellow,
      ),
      home: EnergyHomePage(),
    );
  }
}

class EnergyHomePage extends StatelessWidget {
  // Constructor of EnergyHomePage
  EnergyHomePage({Key? key}) : super(key: key);

  final altitudeChangeValue = TextEditingController();
  final velocityChangeValue = TextEditingController();
  final weightValue = TextEditingController();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text('Flutter Energy App')),
      body: ChangeNotifierProvider(
        key: const Key("ChangeNotifierProvider"),
        create: (_) => EnergyModelProvider(),
        child: Center(
          child: Column(
            children: [
              // Textfield to enter altitude change value
              TextField(
                key: const Key("AltitudeChange"),
                controller: altitudeChangeValue,
                keyboardType: TextInputType.number,
                decoration: InputDecoration(
                  labelText: 'Enter altitude change in meter:',
                  suffixText: 'm',
                    suffixIcon: IconButton(
                      onPressed: weightValue.clear,
                      icon: Icon(Icons.clear),
                    )
                  ),
              ),
              // Textfield to enter velocity change value
              TextField(
                key: const Key("VelocityChange"),
                controller: velocityChangeValue,
                keyboardType: TextInputType.number,
                decoration: InputDecoration(
                  labelText: 'Enter velocity change in m/s:',
                  suffixText: 'm/s',
                    suffixIcon: IconButton(
                      onPressed: weightValue.clear,
                      icon: Icon(Icons.clear),
                    )
                ),
              ),
              // Textfield to enter weight value
              TextField(
                key: const Key("WeightValue"),
                controller: weightValue,
                keyboardType: TextInputType.number,
                decoration: InputDecoration(
                  labelText: 'Enter weight of object in kg:',
                  suffixText: 'kg',
                  suffixIcon: IconButton(
                    onPressed: weightValue.clear,
                    icon: Icon(Icons.clear),
                  )
                  ),
              ),
              Consumer<EnergyModelProvider>(
                builder: (context, model, child) => Column(
                  children: [
                    TextButton(
                        key: const Key("ButtonEnergyInJoule"),
                        style: TextButton.styleFrom(
                          foregroundColor: Colors.green,
                        ),
                        onPressed: () => model.calculateEnergyInJoule(weightValue.text, velocityChangeValue.text),
                        child: Text('Press to calculate energy in joule')
                    ),
                    TextButton(
                        key: const Key("ButtonPotentialEnergy"),
                        style: TextButton.styleFrom(
                        foregroundColor: Colors.red,
                      ),
                      onPressed: () => model.calculateEnergyPotential(weightValue.text, altitudeChangeValue.text),
                      child: Text('Press to calculate Potential energy')
                    ),
                    TextButton(
                        key: const Key("ButtonKineticEnergy"),
                        style: TextButton.styleFrom(
                          foregroundColor: Colors.blueAccent,
                        ),
                      onPressed: () => model.calculateEnergyKinetic(weightValue.text, velocityChangeValue.text),
                      child: Text('Press to calculate Kinetic energy')
                    ),
                    TextButton(
                        key: const Key("ButtonLiterWater"),
                        style: TextButton.styleFrom(
                          foregroundColor: Colors.grey,
                        ),
                        onPressed: () => model.calculateLiterToHeatWater(),
                        child: Text('Press to calculate liter to heat water')
                    ),
                    TextButton(
                        key: const Key("ButtonKilogrammIron"),
                        style: TextButton.styleFrom(
                          foregroundColor: Colors.purple,
                        ),
                        onPressed: () => model.calculateKgToHeatIron(),
                        child: Text('Press to calculate kg to heat iron')
                    ),
                    Text(
                        'Energy in Joule: ${model.energyInJoule} J'),
                    Text(
                        'Potential Energy in Joule: ${model.potentialEnergy} J'),
                    Text(
                        'Kinetic Energy in Joule: ${model.kineticEnergy} J'),
                    Text(
                        'Amount of water you could heat water: ${model.literWaterToHeat} L'),
                    Text(
                        'Amount of iron you could heat: ${model.kilogrammIronToHeat} kg'),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
    throw UnimplementedError();
  }
}