플러터 계산기 남의 코드 읽기 4 -> 원가계산기 어플 만들때 참조할것

출처 -fluttercalculator/home_page.dart at master · iampawan/fluttercalculator (github.com)

 

import 'package:flutter/material.dart';

 

1. 함수읽기 

StatefulWidget 사용 -> var 추론으로 변수 num1, num2 , sum = 0  선언 

TextEditingController  사용  -> t1 , t2로 변수 선언 text  기본값으로 0 

 

함수식만들기 

doAddition -> 더하기 함수 이름 

t1,t2에 입력된 값은 -> num1,num2로 불러와지고 sum = num1+num2

 

 

더하기 버튼을 만들고 

 MaterialButton(
                  child: new Text("+"),
                  color: Colors.greenAccent,
                  onPressed: doAddition, -> 버튼을 누르면 doAddition 함수 실행으로 연결되게 만듬 

 

 

클리어 함수 

void doClear() {
    setState(() {
      t1.text = "0";
      t2.text = "0";
    });
  }

 

2.위젯읽기 

 

텍스트컨트롤러 t1, t2로 입력 , hint 기능을 사용해서 숫자만 입력하게끔 알려줌 

t1,t2로 불러드린 값들이 num1,num2으로 저장되고 sum의 값은 아래 위젯에 보여주게됨

new Container(
        padding: const EdgeInsets.all(40.0),
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            new Text(
              "Output : $sum",
              style: new TextStyle(
                  fontSize: 20.0,
                  fontWeight: FontWeight.bold,
                  color: Colors.purple),

class HomePage extends StatefulWidget {
  @override
  State createState() => new HomePageState();
}

class HomePageState extends State<HomePage> {
  var num1 = 0, num2 = 0, sum = 0;

  final TextEditingController t1 = new TextEditingController(text: "0");
  final TextEditingController t2 = new TextEditingController(text: "0");

  void doAddition() {
    setState(() {
      num1 = int.parse(t1.text);
      num2 = int.parse(t2.text);
      sum = num1 + num2;
    });
  }

  void doSub() {
    setState(() {
      num1 = int.parse(t1.text);
      num2 = int.parse(t2.text);
      sum = num1 - num2;
    });
  }

  void doMul() {
    setState(() {
      num1 = int.parse(t1.text);
      num2 = int.parse(t2.text);
      sum = num1 * num2;
    });
  }

  void doDiv() {
    setState(() {
      num1 = int.parse(t1.text);
      num2 = int.parse(t2.text);
      sum = num1 ~/ num2;
    });
  }

  void doClear() {
    setState(() {
      t1.text = "0";
      t2.text = "0";
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text("Calculator"),
      ),
      body: new Container(
        padding: const EdgeInsets.all(40.0),
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new Text(
              "Output : $sum",
              style: new TextStyle(
                  fontSize: 20.0,
                  fontWeight: FontWeight.bold,
                  color: Colors.purple),
            ),
            new TextField(
              keyboardType: TextInputType.number,
              decoration: new InputDecoration(hintText: "Enter Number 1"),
              controller: t1,
            ),
            new TextField(
              keyboardType: TextInputType.number,
              decoration: new InputDecoration(hintText: "Enter Number 2"),
              controller: t2,
            ),
            new Padding(
              padding: const EdgeInsets.only(top: 20.0),
            ),
            new Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: <Widget>[
                new MaterialButton(
                  child: new Text("+"),
                  color: Colors.greenAccent,
                  onPressed: doAddition,
                ),
                new MaterialButton(
                  child: new Text("-"),
                  color: Colors.greenAccent,
                  onPressed: doSub,
                ),
              ],
            ),
            new Padding(
              padding: const EdgeInsets.only(top: 20.0),
            ),
            new Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: <Widget>[
                new MaterialButton(
                  child: new Text("*"),
                  color: Colors.greenAccent,
                  onPressed: doMul,
                ),
                new MaterialButton(
                  child: new Text("/"),
                  color: Colors.greenAccent,
                  onPressed: doDiv,
                ),
              ],
            ),
            new Padding(
              padding: const EdgeInsets.only(top: 20.0),
            ),
            new Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                new MaterialButton(
                  child: new Text("Clear"),
                  color: Colors.greenAccent,
                  onPressed: doClear,
                ),
              ],
            )
          ],
        ),
      ),
    );
  }
}