https://github.com/codingspecialist/Flutter-BMI

font_awesome_flutter: ^10.7.0

import 'package:flutter/material.dart';
import '../constants.dart';

class BottomButton extends StatelessWidget {
  BottomButton({required this.onTap, required this.buttonTitle});

  final onTap;
  final String buttonTitle;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        child: Center(
            child: Text(
              buttonTitle,
              style: kLargeButtonTextStyle,
            )),
        color: kBottomContainerColor,
        margin: EdgeInsets.only(top: 10.0),
        width: double.infinity,
        height: kBottomContainerHeight,
      ),
    );
  }
}

import 'package:flutter/material.dart';
import '../constants.dart';

class IconContent extends StatelessWidget {
  final IconData mIcon;
  final String mLabel;

  IconContent({required this.mIcon, required this.mLabel});

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Icon(
          mIcon,
          size: 80.0,
        ),
        SizedBox(
          height: 15.0,
        ),
        Text(
          mLabel,
          style: kLabelTextStyle,
        )
      ],
    );
  }
}

import 'package:flutter/material.dart';

class ReusableCard extends StatelessWidget {
  final mColor;
  final cardChild;
  final onPress;

  ReusableCard({required this.mColor, this.cardChild, this.onPress});

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onPress,
      child: Container(
        child: cardChild,
        margin: EdgeInsets.all(15.0),
        decoration: BoxDecoration(
            color: mColor, borderRadius: BorderRadius.circular(10.0)),
      ),
    );
  }
}

import 'package:flutter/material.dart';

class RoundIconButton extends StatelessWidget {
  RoundIconButton({required this.icon, required this.onPressed});

  final icon;
  final onPressed; //dynamic type

  @override
  Widget build(BuildContext context) {
    return RawMaterialButton(
      child: Icon(icon),
      onPressed: onPressed,
      elevation: 0.0,
      // 그림자는 버튼이 클릭상태일 때만 발동. 아닐때도 발동하려면 disableElevation 사용
      constraints: BoxConstraints.tightFor(
        width: 56.0,
        height: 56.0,
      ),
      shape: CircleBorder(),
      fillColor: Color(0xFF4C4F5E),
    );
  }
}

import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
import 'package:loginapp/pages/result_page.dart';
import '../calculator_brain.dart';
import '../components/bottom_button.dart';
import '../components/icon_content.dart';
import '../components/reusable_card.dart';
import '../components/round_icon_button.dart';
import '../constants.dart';

enum Gender { male, female }

class InputPage extends StatefulWidget {
  @override
  _InputPageState createState() => _InputPageState();
}

class _InputPageState extends State<InputPage> {
  Gender? selectedGender;
  int height = 180;
  int weight = 60;
  int age = 20;

  @override
  Widget build(BuildContext context) {
    print('BuildContext : ' + context.hashCode.toString());
    return Scaffold(
      appBar: AppBar(
        title: Center(child: Text('BMI CALCULATOR')),
      ),
      body: Column(
        //crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          Expanded(
              child: Row(
                // Row로 감싸면
                children: <Widget>[
                  Expanded(
                    // FlatButton은 material Design이 적용되어 있어서 안에 item크기에 맞춰서
                    // 크기가 줄어들어 버린다. 그래서 GestureDetector를 쓴다.
                    child: ReusableCard(
                      onPress: () {
                        setState(() {
                          selectedGender = Gender.male;
                        });
                      },
                      // ternary operator (삼항 연산자)
                      mColor: selectedGender == Gender.male
                          ? kActiveCardColor
                          : kInactiveCardColor,
                      cardChild: IconContent(
                        mIcon: FontAwesomeIcons.mars,
                        mLabel: 'MALE',
                      ),
                    ),
                  ),
                  Expanded(
                    child: ReusableCard(
                      onPress: () {
                        setState(() {
                          selectedGender = Gender.female;
                        });
                      },
                      mColor: selectedGender == Gender.female
                          ? kActiveCardColor
                          : kInactiveCardColor,
                      cardChild: IconContent(
                        mIcon: FontAwesomeIcons.venus,
                        mLabel: 'FEMALE',
                      ),
                    ),
                  ),
                ],
              )),
          Expanded(
            child: ReusableCard(
              mColor: kActiveCardColor,
              cardChild: Column(
                // 칼럼에 Expanded면 width 비율이 꽉차지 않는다. Row로 감싸면 해결된다. 혹은 strech를 준다.
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Text(
                    'HEIGHT',
                    style: kLabelTextStyle,
                  ),
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.baseline,
                    textBaseline: TextBaseline.alphabetic,
                    // 글자 baseline을 맞출 때 함께 줘야하는 속성
                    children: <Widget>[
                      Text(
                        height.toString(),
                        style: kNumberTextStyle,
                      ),
                      Text(
                        'cm',
                        style: kLabelTextStyle,
                      )
                    ],
                  ),
                  SliderTheme(
                    data: SliderTheme.of(context),
                    child: Slider(
                      value: height.toDouble(),
                      min: 120.0,
                      max: 220.0,
                      onChanged: (double newValue) {
                        setState(() {
                          height = newValue
                              .round(); // toInt는 소수점을 짤라내고 round는 반올림 해서 정수로 만들어준다.
                        });
                      },
                    ),
                  ),
                ],
              ),
            ),
          ),
          Expanded(
            child: Row(
              children: <Widget>[
                Expanded(
                  child: ReusableCard(
                    mColor: kActiveCardColor,
                    cardChild: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: <Widget>[
                        Text(
                          'WEIGHT',
                          style: kLabelTextStyle,
                        ),
                        Text(
                          weight.toString(),
                          style: kNumberTextStyle,
                        ),
                        Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: <Widget>[
                            RoundIconButton(
                              onPressed: () {
                                setState(() {
                                  weight--;
                                });
                              },
                              icon: FontAwesomeIcons.minus,
                            ),
                            SizedBox(
                              width: 10.0,
                            ),
                            RoundIconButton(
                              onPressed: () {
                                setState(() {
                                  weight++;
                                });
                              },
                              icon: FontAwesomeIcons.plus,
                            )
                          ],
                        ),
                      ],
                    ),
                  ),
                ),
                Expanded(
                  child: ReusableCard(
                    mColor: kActiveCardColor,
                    cardChild: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: <Widget>[
                        Text(
                          'AGE',
                          style: kLabelTextStyle,
                        ),
                        Text(
                          age.toString(),
                          style: kNumberTextStyle,
                        ),
                        Row(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: <Widget>[
                            RoundIconButton(
                              onPressed: () {
                                setState(() {
                                  age--;
                                });
                              },
                              icon: FontAwesomeIcons.minus,
                            ),
                            SizedBox(
                              width: 10.0,
                            ),
                            RoundIconButton(
                              onPressed: () {
                                setState(() {
                                  age++;
                                });
                              },
                              icon: FontAwesomeIcons.plus,
                            )
                          ],
                        ),
                      ],
                    ),
                  ),
                ),
              ],
            ),
          ),
          BottomButton(
            buttonTitle: 'CALCULATE',
            onTap: () {
              // context 에 대해서 참고 (builder를 통해 context를 넘길 수 있다.)
              // <https://javaexpert.tistory.com/978>
              print('context : ' + context.hashCode.toString());

              CalculatorBrain calc = CalculatorBrain(height: height, weight: weight);
              print('result ${calc.calculateBMI()}');
              print('height ${height}');
              print('weight ${weight}');
              Navigator.push(context, MaterialPageRoute(builder: (context) {
                print('MaterialPageRoute context : ' +
                    context.hashCode.toString());
                return ResultPage(
                  bmiResult: calc.calculateBMI(),
                  resultText: calc.getResult(),
                  interpretation: calc.getInterpretation(),
                );
              }));
            },
          )
        ],
      ),
    );
  }
}

import 'package:flutter/material.dart';

import '../components/bottom_button.dart';
import '../components/reusable_card.dart';
import '../constants.dart';

class ResultPage extends StatelessWidget {

  final bmiResult;
  final resultText;
  final interpretation;

  ResultPage({required this.bmiResult, required this.resultText, required this.interpretation});

  @override
  Widget build(BuildContext context) {
    print('ResultPage : ' + context.hashCode.toString());
    return Scaffold(
      appBar: AppBar(
        title: Text(
          'BMI CALCULATOR',
        ),
      ),
      body: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: <Widget>[
          Expanded(
            child: Container(
              alignment: Alignment.center,
              child: Text('Your Result',
                  style: kTitleTextStyle),
            ),
          ),
          Expanded(
            flex: 5,
            child: ReusableCard(
              mColor: kActiveCardColor,
              cardChild: Column(
                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: <Widget>[
                  Text(
                    resultText.toUpperCase(),
                    style: kResultTextStyle,
                  ),
                  Text(
                    bmiResult,
                    style: kBMITextStyle,
                  ),
                  Text(
                    interpretation,
                    style: kBodyTextStyle,
                    textAlign: TextAlign.center,
                  ),
                ],
              ),
            ),
          ),
          BottomButton(
            buttonTitle: 'RE-CALCULATE',
            onTap: () {
              Navigator.pop(context);
            },
          ),
        ],
      ),
    );
  }
}

import 'dart:math';

class CalculatorBrain {

  final int height;
  final int weight;
  late double _bmi; // private 변수는 언더스코어를 붙인다.

  CalculatorBrain({required this.height, required this.weight});

  String calculateBMI(){
    _bmi = weight / pow(height/100, 2); // 제곱할 때 사용하는 함수
    print('bmi : ${_bmi}');
    return _bmi.toStringAsFixed(1);  // 소수점 이하 개수 정하는 함수
  }

  String getResult(){
    if(_bmi >= 25){
      return 'Overweight';
    }else if (_bmi > 18.5){
      return 'Normal';
    }else {
      return 'Underweight';
    }
  }

  String getInterpretation(){
    if(_bmi >= 25){
      return 'You have a higher than normal body weight. Try to exercise more.';
    }else if (_bmi > 18.5){
      return 'You have a normal body weight. Good job!';
    }else {
      return 'You have a lower than normal body weight. You can eat a bit more.';
    }
  }

}

import 'package:flutter/material.dart';

// 디자인 파일 naming convention => k with 낙타표기법
const kBottomContainerHeight = 80.0;
const kActiveCardColor = Color(0xFF1D1E33);
const kInactiveCardColor = Color(0xFF111328);
const kBottomContainerColor = Color(0xFFEB1555);

const kLabelTextStyle = TextStyle(
  fontSize: 18.0,
  color: Color(0xFF8D8E98),
);

const kNumberTextStyle = TextStyle(
    fontSize: 50.0,
    fontWeight: FontWeight.w900
);

const kLargeButtonTextStyle = TextStyle(
  fontSize: 25.0,
  fontWeight: FontWeight.bold,
);

const kTitleTextStyle = TextStyle(
  fontSize: 50.0,
  fontWeight: FontWeight.bold,
);

const kResultTextStyle = TextStyle(
  color: Color(0xFF24D876),
  fontSize: 22.0,
  fontWeight: FontWeight.bold,
);

const kBMITextStyle = TextStyle(
  fontSize: 100.0,
  fontWeight: FontWeight.bold,
);

const kBodyTextStyle = TextStyle(
  fontSize: 22.0,
);

import 'package:flutter/material.dart';
import 'package:loginapp/pages/input_page.dart';

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

class BMICalculator extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData.dark().copyWith(
        sliderTheme: SliderTheme.of(context).copyWith(
          activeTrackColor: Colors.white,
          inactiveTrackColor: Color(0xFF8D8E98),
          thumbColor: Color(0xFFEB1555),
          overlayColor: Color(0x1fEB1555),
          thumbShape: RoundSliderThumbShape(enabledThumbRadius: 15.0),
          overlayShape: RoundSliderOverlayShape(overlayRadius: 30.0),
        ),
        primaryColor: Color(0xFF0A0E21),
        scaffoldBackgroundColor: Color(0xFF0A0E21),
      ),
      home: InputPage(),
    );
  }
}