Java swing实现简单计算器的开发

package calclutor;

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Calculator extends JFrame {

public static void main(String[] args) {
// Create application frame.
Calculator frame = new Calculator();

frame.setTitle("Calculator");
frame.setSize(240, 320);
frame.setResizable(false);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);

frame.init();

// Show frame
frame.setVisible(true);
}

private void init()
{
textField = new JTextField();
textField.setEditable(false);
textField.setHorizontalAlignment (JTextField.RIGHT);
JPanel panel = new JPanel();
panel.setLayout(new GridLayout(4, 4));

Container container = getContentPane();
container.add(textField, BorderLayout.NORTH);
container.add(panel, BorderLayout.CENTER);

panel.add(useButton('7'));
panel.add(useButton('8'));
panel.add(useButton('9'));
panel.add(useButton('+'));
panel.add(useButton('4'));
panel.add(useButton('5'));
panel.add(useButton('6'));
panel.add(useButton('-'));
panel.add(useButton('1'));
panel.add(useButton('2'));
panel.add(useButton('3'));
panel.add(useButton('*'));
panel.add(useButton('0'));
panel.add(useButton('.'));
panel.add(useButton('='));
panel.add(useButton('/'));
}

public JButton useButton (final char key)
{
JButton button = new JButton(String.valueOf(key));

button.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
JButton btn = (JButton) event.getSource();
char key2 = btn.getText().charAt(0);

action(key2);
}
});
button.addKeyListener(new KeyAdapter()
{
public void keyReleased(KeyEvent event)
{
char key2 = event.getKeyChar ();

//if(key2 != key)
//  return;

action(key2);
}
});

return button;
}

private void action(char key2)
{
if(reop)
{
textField.setText("");
reop = false;
}

switch(key2)
{
case '+':
v1 = Double.parseDouble(textField.getText());
textField.setText("");
operator = '+';
break;
case '-':
v1 = Double.parseDouble(textField.getText());
textField.setText("");
operator = '-';
break;
case '*':
v1 = Double.parseDouble(textField.getText());
textField.setText("");
operator = '*';
break;
case '/':
v1 = Double.parseDouble(textField.getText());
textField.setText("");
operator = '/';
break;
case '=':
reop = true;
v2 = Double.parseDouble(textField.getText());
switch(operator)
{
case '+':
value = v1 + v2;
break;
case '-':
value = v1 - v2;
break;
case '*':
value = v1 * v2;
break;
case '/':
value = v1 / v2;
break;
default: ;
}
textField.setText(String.valueOf(value));
break;
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '0':
case '.':
String text = textField.getText() + key2;
textField.setText(text);
break;
default: ;
}
}
private JTextField textField;
private double v1, v2, value;
private char operator;
private boolean reop = false;
}