用java编写一个简易的计算器代码

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

/*使用java 语言开发一个简易计算器

*

*

*/

public class TestJsq extends JFrame implements ActionListener, KeyListener { private JTextField jtf;

private JButton jb_bk, jb_ce, jb_c;

private String xs = "";

private double sum = 0;

private int fh;

public static void main(String[] args) {

new TestJsq().creatCUI();

}

public void creatCUI() {

JFrame jf = new JFrame();

jf.setTitle("计算器");

jtf = new JTextField("0.");

jtf.setHorizontalAlignment(JTextField.RIGHT);

jf.add(jtf, BorderLayout.NORTH);

JPanel jp_main = new JPanel(new BorderLayout());

jf.add(jp_main);

JPanel jp1 = new JPanel(new GridLayout(1, 3, 1, 1));

jb_bk = new JButton("Backspace");

jb_bk.setForeground(Color.RED);

jb_bk.addActionListener(this);

jb_ce = new JButton("CE");

jb_ce.setForeground(Color.RED);

jb_ce.addActionListener(this);

jb_c = new JButton("C");

jb_c.setForeground(Color.RED);

jb_c.addActionListener(this);

jp1.add(jb_bk);

jp1.add(jb_ce);

jp1.add(jb_c);

jp_main.add(jp1, BorderLayout.NORTH);

JPanel jp2 = new JPanel(new GridLayout(4, 5, 1, 1));

String str[] = { "7", "8", "9", "/", "sqrt", "4", "5", "6", "*", "%", "1", "2", "3", "-", "1/x", "0", "+/-", ".", "+", "=" };

for (int i = 0; i < 20; i++) {

JButton jb = new JButton(str[i]);

jb.addActionListener(this);

jb.setForeground(Color.blue);

if (i == 3 || i == 8 || i == 13 || i == 18 || i == 19) {

jb.setForeground(Color.RED);

}

jp2.add(jb);

}

jp_main.add(jp2, BorderLayout.CENTER);

jf.setResizable(false);

jf.setBounds(50, 50, 350, 350);

jf.setVisible(true);

}

@Override

public void actionPerformed(ActionEvent e) {

String s = e.getActionCommand();

if (s.equals("CE") || s.equals("C")) {

xs = "";

jtf.setText("0.");

} else if (s.equals("Backspace")) {

String str = xs.substring(0, xs.length() - 1);

xs = str;

jtf.setText(xs);

} else if (s.equals("7") || s.equals("8") || s.equals("9")

|| s.equals("4") || s.equals("5") || s.equals("6")

|| s.equals("1") || s.equals("2") || s.equals("3")

|| s.equals("0") || s.equals(".")) {

xs = xs + s;