자바 이벤트, 간단한 계산기 연습, 메세지 다이얼로그

package test;

import java.awt.Container;

import java.awt.FlowLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JTextField;

public class Test6 extends JFrame {

JTextField tf1 = new JTextField(10);

JTextField tf2 = new JTextField(10);

JTextField tfResult = new JTextField(10);

JButton btnAdd = new JButton("덧셈");

JButton btnSubtract = new JButton("뺄셈");

JButton btnMultiply = new JButton("곱셈");

JButton btnDivide = new JButton("나눗셈");

public Test6() {

setTitle("간단한 계산기 연습");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Container c = getContentPane();

c.setLayout(new FlowLayout());

c.add(new JLabel("숫자1 : "));

c.add(tf1);

c.add(new JLabel("숫자2 : "));

c.add(tf2);

c.add(btnAdd);

c.add(btnSubtract);

c.add(btnMultiply);

c.add(btnDivide);

c.add(tfResult);

btnAdd.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String strNum1 = tf1.getText().trim();

String strNum2 = tf2.getText().trim();

int num1 = Integer.parseInt(strNum1);

int num2 = Integer.parseInt(strNum2);

int sum = num1 + num2;

tfResult.setText(Integer.toString(sum));

}

});

btnSubtract.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String strNum1 = tf1.getText().trim();

String strNum2 = tf2.getText().trim();

int num1 = Integer.parseInt(strNum1);

int num2 = Integer.parseInt(strNum2);

int sum = num1 - num2;

tfResult.setText(Integer.toString(sum));

}

});

btnMultiply.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String strNum1 = tf1.getText().trim();

String strNum2 = tf2.getText().trim();

int num1 = Integer.parseInt(strNum1);

int num2 = Integer.parseInt(strNum2);

int sum = num1 * num2;

tfResult.setText(Integer.toString(sum));

}

});

btnDivide.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

String strNum1 = tf1.getText().trim();

String strNum2 = tf2.getText().trim();

int num1 = Integer.parseInt(strNum1);

int num2 = Integer.parseInt(strNum2);

int sum = num1 / num2;

tfResult.setText(Integer.toString(sum));

}

});

setSize(220, 250);

setVisible(true);

}

public static void main(String[] args) {

new Test6();

}

}

package test;

import java.awt.Container;

import java.awt.FlowLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JOptionPane;

import javax.swing.JTextField;

public class Test7 extends JFrame {

JTextField tf1 = new JTextField(10);

JTextField tf2 = new JTextField(10);

JTextField tfResult = new JTextField(10);

JButton btnAdd = new JButton("덧셈");

JButton btnSubtract = new JButton("뺄셈");

JButton btnMultiply = new JButton("곱셈");

JButton btnDivide = new JButton("나눗셈");

ActionListener listener = new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

JButton btn = (JButton)e.getSource();

String btnName = btn.getText();

String strNum1 = tf1.getText().trim();

String strNum2 = tf2.getText().trim();

int num1 = Integer.parseInt(strNum1);

int num2 = Integer.parseInt(strNum2);

int result = 0;

if ("덧셈".equals(btnName)) {

result = num1 + num2;

} else if ("뺄셈".equals(btnName)) {

result = num1 - num2;

} else if ("곱셈".equals(btnName)) {

result = num1 * num2;

} else if ("나눗셈".equals(btnName)) {

result = num1 / num2;

}

tfResult.setText(Integer.toString(result));

JOptionPane.showMessageDialog(Test7.this, "결과값:" + result, "결과", JOptionPane.ERROR_MESSAGE);

// JOptionPane.showMessageDialog(Test7.this, "결과값:" + result, "결과", JOptionPane.WARNING_MESSAGE);

// JOptionPane.showMessageDialog(Test7.this, "결과값:" + result, "결과", JOptionPane.INFORMATION_MESSAGE);

}

};

public Test7() {

setTitle("간단한 계산기 연습");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Container c = getContentPane();

c.setLayout(new FlowLayout());

c.add(new JLabel("숫자1 : "));

c.add(tf1);

c.add(new JLabel("숫자2 : "));

c.add(tf2);

c.add(btnAdd);

c.add(btnSubtract);

c.add(btnMultiply);

c.add(btnDivide);

c.add(tfResult);

btnAdd.addActionListener(listener);

btnSubtract.addActionListener(listener);

btnMultiply.addActionListener(listener);

btnDivide.addActionListener(listener);

setSize(220, 250);

setVisible(true);

}

public static void main(String[] args) {

new Test7();

}

}