[JAVA] 계산기 예제 (swing, event, awt, util)

Java 연습겸 어떤 분이 계산기를 올려주셨길래 따라쳐보면서 연습했습니다.

( 원본 : http://djsdj222.blog.me/220170288062 )

import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.util.*; public class Calc extends JFrame { JLabel label; JButton bNum[] = new JButton[10]; JButton plus, minus, multi, div, equal, clear; String inputValue; int result; char lastOp; public static void main(String[] args) { new Calc(); } public Calc() { super("Calcurator"); setBounds(200, 200, 300, 300); setResizable(false); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); label = new JLabel("0", JLabel.RIGHT); label.setFont(new Font("궁서", Font.BOLD, 20)); add(label, BorderLayout.NORTH); JPanel p = new JPanel(new GridLayout(4, 4, 1, 1)); add(p, BorderLayout.CENTER); plus = new JButton("+"); minus = new JButton("-"); multi = new JButton("*"); div = new JButton("/"); equal = new JButton("="); clear = new JButton("C"); int i; for( i=0;i<bNum.length;i++ ) { bNum[i] = new JButton(Integer.toString(i)); } p.add(bNum[7]); p.add(bNum[8]); p.add(bNum[9]); p.add(plus); p.add(bNum[4]); p.add(bNum[5]); p.add(bNum[6]); p.add(minus); p.add(bNum[1]); p.add(bNum[2]); p.add(bNum[3]); p.add(multi); p.add(bNum[0]); p.add(equal); p.add(clear); p.add(div); NumberHandler nh = new NumberHandler(); for( i=0;i<bNum.length;i++ ) { bNum[i].addActionListener(nh); } CalcHandler ch = new CalcHandler(); plus.addActionListener(ch); minus.addActionListener(ch); multi.addActionListener(ch); div.addActionListener(ch); equal.addActionListener(ch); clear.addActionListener(ch); setVisible(true); } // number Event class NumberHandler implements ActionListener { public void actionPerformed(ActionEvent e) { String s = e.getActionCommand(); if(inputValue == null) { if( s.equals("0")) return ; else inputValue = new String(); } if( inputValue.length() >= 9) return; inputValue += s; label.setText(inputValue); } } // other button Event class CalcHandler implements ActionListener { public void actionPerformed(ActionEvent e) { JButton source = (JButton)e.getSource(); int value; if( source == clear ) { label.setText("0"); inputValue = null; lastOp = 0; result = 0; return ; } if( inputValue != null ) { value = Integer.parseInt(inputValue); switch(lastOp) { case '+': result += value; break; case '-': result -= value; break; case '*': result *= value; break; case '/': result /= value; break; default : result = value; break; } label.setText(Integer.toString(result)); } inputValue = null; lastOp = source.getText().charAt(0); } } }