GP Calculator Flutter

main.dart

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Gp Calculator',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Vibes and Inshallah GP Calculator'),
    );
  }
}

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

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

class _MyHomePageState extends State<MyHomePage> {
  List<Map<String, dynamic>> gpCalculator = [];

  Map<String, int> grades = {"A": 5, "B": 4, "C": 3, "D": 2, "E": 1, "F": 0};
  final List gradesList = ['A', 'B', 'C', 'D', 'E', 'F'];

  String currentGP = "0";

  void add() {
    setState(() {
      gpCalculator.add({"course": '', 'grade': 'A', 'unit': 0});
    });
  }

  void remove(index) {
    setState(() {
      gpCalculator.removeAt(index);
    });
  }

  void calculate() {
    int TQP = 0;
    int units = 0;

    gpCalculator.forEach((value) {
      var grade = grades[value['grade'].toString()];

      print(value);
      print(grade);

      TQP += int.parse(value['unit']) * grade;
      units += value['unit'];
    });

    print(TQP);
    print(units);

    // setState(() {
    //   currentGP = (TQP / units).toString();
    // });
  }

  Widget buildForm(int index) {
    // dynamic currentItem = gpCalculator[index];
    return Container(
      height: 100,
      width: double.infinity,
      child: Row(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        key: Key('' + index.toString()),
        children: [
          SizedBox(
            child: TextField(
              onChanged: (value) => gpCalculator[index]['course'] = value,
              decoration: InputDecoration(hintText: 'Input Course'),
            ),
            width: 100,
          ),
          SizedBox(
            width: 80,
            child: DropdownButton<dynamic>(
              value: gpCalculator[index]['grade'],
              hint: Text(
                'Select grade',
                style: TextStyle(fontSize: 10),
              ),
              onChanged: (value) {
                setState(() {
                  gpCalculator[index]['grade'] = value;
                });
              },
              items: gradesList.map((value) {
                return DropdownMenuItem<dynamic>(
                  child: Text(value.toString()),
                  value: value,
                );
              }).toList(),
            ),
          ),
          SizedBox(
            width: 100,
            child: TextField(
              keyboardType: TextInputType.number,
              onChanged: (value) => gpCalculator[index]['unit'] = value,
              decoration: InputDecoration(hintText: 'Input Unit'),
            ),
          ),
          IconButton(
            onPressed: () => remove(index),
            icon: Icon(Icons.remove_circle),
            color: Colors.red,
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Container(
        padding: EdgeInsets.all(16),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              currentGP,
              style: TextStyle(fontSize: 20),
            ),
            MaterialButton(
              color: Colors.red,
              child: Text('ADD'),
              onPressed: () => add(),
            ),
            Expanded(
                child: Column(
              children: List.generate(
                  gpCalculator.length, (index) => buildForm(index),
                  growable: true),
            )),
            MaterialButton(
              color: Colors.red,
              child: Text('Calculate!'),
              onPressed: () => calculate(),
            ),
          ],
        ),
      ),
    );
  }
}