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jamesshah/calculator.dart

Created August 4, 2020 12:12
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  1. jamesshah created this gist Aug 4, 2020.
    243 changes: 243 additions & 0 deletions calculator.dart
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,243 @@
    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(debugShowCheckedModeBanner: false, home: Calculator());
    }
    }

    class Calculator extends StatefulWidget {
    @override
    _CalculatorState createState() => _CalculatorState();
    }

    class _CalculatorState extends State<Calculator> {
    dynamic displaytxt = 20;

    Widget buildButton(String buttonText, Color buttonColor, Color textColor) {
    return Container(
    child: RaisedButton(
    onPressed: () => calculation(buttonText),
    child: Text(
    "$buttonText",
    style: TextStyle(fontSize: 30, color: textColor),
    ),
    shape: CircleBorder(),
    color: buttonColor,
    padding: EdgeInsets.all(20),
    ),
    );
    }

    @override
    Widget build(BuildContext context) {
    return Scaffold(
    backgroundColor: Colors.black,
    body: Padding(
    padding: EdgeInsets.symmetric(horizontal: 3),
    child: Column(
    mainAxisAlignment: MainAxisAlignment.end,
    children: [
    Row(
    mainAxisAlignment: MainAxisAlignment.end,
    children: <Widget>[
    Padding(
    padding: const EdgeInsets.all(10.0),
    child: Text(
    text,
    textAlign: TextAlign.left,
    style: TextStyle(
    color: Colors.white,
    fontSize: 100,
    ),
    ),
    )
    ],
    ),
    Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
    buildButton("AC", Colors.grey, Colors.black),
    buildButton("+/-", Colors.grey, Colors.black),
    buildButton("%", Colors.grey, Colors.black),
    buildButton("/", Colors.amber[700], Colors.black)
    ],
    ),
    SizedBox(
    height: 10,
    ),
    Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
    buildButton("7", Colors.grey[850], Colors.white),
    buildButton("8", Colors.grey[850], Colors.white),
    buildButton("9", Colors.grey[850], Colors.white),
    buildButton("x", Colors.amber[700], Colors.black)
    ],
    ),
    SizedBox(
    height: 10,
    ),
    Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
    buildButton("4", Colors.grey[850], Colors.white),
    buildButton("5", Colors.grey[850], Colors.white),
    buildButton("6", Colors.grey[850], Colors.white),
    buildButton("-", Colors.amber[700], Colors.black)
    ],
    ),
    SizedBox(
    height: 10,
    ),
    Row(
    mainAxisAlignment: MainAxisAlignment.spaceEvenly,
    children: [
    buildButton("1", Colors.grey[850], Colors.white),
    buildButton("2", Colors.grey[850], Colors.white),
    buildButton("3", Colors.grey[850], Colors.white),
    buildButton("+", Colors.amber[700], Colors.black)
    ],
    ),
    SizedBox(
    height: 10,
    ),
    Row(
    children: [
    RaisedButton(
    onPressed: () => calculation("0"),
    padding: EdgeInsets.fromLTRB(34, 20, 124, 20),
    shape: StadiumBorder(),
    child: Text(
    "0",
    style: TextStyle(fontSize: 30, color: Colors.white),
    ),
    color: Colors.grey[850],
    ),
    buildButton(".", Colors.grey[850], Colors.white),
    buildButton("=", Colors.grey[850], Colors.white),
    ],
    ),
    SizedBox(
    height: 10,
    )
    ],
    ),
    ),
    );
    }

    dynamic text = '0';
    dynamic res = '';
    double numOne = 0;
    double numTwo = 0;

    dynamic result = '';
    dynamic finalResult = '';
    dynamic op = '';
    dynamic preOp = '';

    void calculation(btnText) {
    if (btnText == 'AC') {
    text = '0';
    res = '';
    numOne = 0;
    numTwo = 0;
    result = '';
    finalResult = '0';
    op = '';
    preOp = '';
    } else if (op == '=' && btnText == '=') {
    if (preOp == '+') {
    finalResult = add();
    } else if (preOp == '-') {
    finalResult = sub();
    } else if (preOp == 'x') {
    finalResult = mul();
    } else if (preOp == '/') {
    finalResult = div();
    }
    } else if (btnText == '+' ||
    btnText == '-' ||
    btnText == 'x' ||
    btnText == '/' ||
    btnText == '=') {
    if (numOne == 0) {
    numOne = double.parse(result);
    } else {
    numTwo = double.parse(result);
    }

    if (op == '+') {
    finalResult = add();
    } else if (op == '-') {
    finalResult = sub();
    } else if (op == 'x') {
    finalResult = mul();
    } else if (op == '/') {
    finalResult = div();
    }
    preOp = op;
    op = btnText;
    result = '';
    } else if (btnText == '%') {
    result = numOne / 100;
    finalResult = doesContainDecimal(result);
    } else if (btnText == '.') {
    if (!result.toString().contains('.')) {
    result = result.toString() + '.';
    }
    finalResult = result;
    } else if (btnText == '+/-') {
    result.toString().startsWith('-')
    ? result = result.toString().substring(1)
    : result = '-' + result.toString();
    finalResult = result;
    } else {
    result = result + btnText;
    finalResult = result;
    }
    setState(() {
    text = finalResult;
    });
    }

    String add() {
    result = (numOne + numTwo).toString();
    numOne = double.parse(result);
    return doesContainDecimal(result);
    }

    String sub() {
    result = (numOne - numTwo).toString();
    numOne = double.parse(result);
    return doesContainDecimal(result);
    }

    String mul() {
    result = (numOne * numTwo).toString();
    numOne = double.parse(result);
    return doesContainDecimal(result);
    }

    String div() {
    result = (numOne / numTwo).toString();
    numOne = double.parse(result);
    return doesContainDecimal(result);
    }

    String doesContainDecimal(dynamic result) {
    if (result.toString().contains('.')) {
    List<String> splitDecimal = result.toString().split('.');
    if (!(int.parse(splitDecimal[1]) > 0))
    return result = splitDecimal[0].toString();
    }
    return result;
    }
    }