Question

编写一个Java小应用程序，设计4个按钮，分别命名为“加”、“差”、“积”、“除”...

编写一个Java小应用程序，设计4个按钮，分别命名为“加”、“差”、“积”、“除”以及3个文本框。单击相应的按钮，两个文本框的数字做算术运算，在第3个文本框中显示结果。要求处理NumberFormatException。

本题是Java小程序，题来自JAVA 2 实用教程(第二版) 清华大学出版社。
130页 第十章 习题3

急需这道题的完整代码。
请各位Java行家 写清楚。
不是jsp做

恩，最迟在明天下午两点之前。我就回学校了。在这先谢谢各位了。

回答者：little_goblin - 初入江湖 二级 7-7 09:19
很感谢你的回答，但这似乎不是我要的，我不要jsp的

Answer 1

 
 
 
可以这样写：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class SimpleCalc extends JApplet implements ActionListener {
    public static void main(String[] args) {    // 这 main 方法只在调试时用到
        SimpleCalc sc = new SimpleCalc();
        sc.init();

        JFrame f = new JFrame();
        f.add(sc);
        f.pack();
        f.setVisible(true);
        f.setLocationRelativeTo(null);
        f.setDefaultCloseOperation(f.EXIT_ON_CLOSE);
    }

    private JTextField num1 = new JTextField(),
                       num2 = new JTextField(),
                       result = new JTextField(20);

    public void init() {
        setLayout(new GridLayout(0, 2, 2, 2));
        add(num1);
        add(num2);
        for (String cmd: new String[]{"加", "差", "积", "除"}) {
            JButton b = new JButton(cmd);
            b.addActionListener(this);
            add(b);
        }
        add(new JLabel("结果：", JLabel.TRAILING));
        add(result);
        result.setEditable(false);
        getRootPane().setBorder(BorderFactory.createRaisedBevelBorder());
    }

    public void actionPerformed(ActionEvent e) {
        try {
            double n1 = Double.valueOf(num1.getText()),
                   n2 = Double.valueOf(num2.getText());
            String cmd = e.getActionCommand();
            if (cmd == "加") result.setText(n1 + n2 + "");
            if (cmd == "差") result.setText(n1 - n2 + "");
            if (cmd == "积") result.setText(n1 * n2 + "");
            if (cmd == "除") result.setText(n1 / n2 + "");

        } catch (NumberFormatException nfe) {
            JOptionPane.showMessageDialog(this, "数字个数或格式错误！",
                    "", JOptionPane.ERROR_MESSAGE);
        }
    }
}
 
 
 

Answer 2

//呵呵，俺又来了......
//这次是运行过的,绝对没问题，保存为Canlulater.java就可以直接运行了
//如果你不满意,还有要求直接加我qq,我就不信我不行----516041982
import java.awt.Toolkit;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import java.awt.Dimension;
import java.awt.*;

import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.Rectangle;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Canlulater {
boolean packFrame = false;

public Jsq() {
JsqFrame frame = new JsqFrame();

if (packFrame) {
frame.pack();
} else {
frame.validate();
}

// Center the window
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
Dimension frameSize = frame.getSize();
if (frameSize.height > screenSize.height) {
frameSize.height = screenSize.height;
}
if (frameSize.width > screenSize.width) {
frameSize.width = screenSize.width;
}
frame.setLocation((screenSize.width - frameSize.width) / 2,
(screenSize.height - frameSize.height) / 2);
frame.setVisible(true);
}

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
try {
UIManager.setLookAndFeel(UIManager.
getSystemLookAndFeelClassName());
} catch (Exception exception) {
exception.printStackTrace();
}

new Jsq();
}
});
}
}

class JsqFrame extends JFrame {
JPanel contentPane;
JLabel lblFirst = new JLabel();
JLabel lblThird = new JLabel();
JTextField txtFirst = new JTextField();
JTextField txtThird = new JTextField();
JLabel lblFifth = new JLabel();
JTextField txtForth = new JTextField();
JButton btn1 = new JButton();
JButton btn2 = new JButton();
JButton btn3 = new JButton();
JButton btn4 = new JButton();
public JsqFrame() {
try {
setDefaultCloseOperation(EXIT_ON_CLOSE);
jbInit();
} catch (Exception exception) {
exception.printStackTrace();
}
}

/**
* Component initialization.
*
* @throws java.lang.Exception
*/
private void jbInit() throws Exception {
this.setResizable(false);
contentPane = (JPanel) getContentPane();
contentPane.setLayout(null);
setSize(new Dimension(400, 300));
setTitle("Frame Title");
lblFirst.setFont(new java.awt.Font("宋体", Font.PLAIN, 16));
lblFirst.setText("第一个数");
lblFirst.setBounds(new Rectangle(56, 28, 93, 34));
lblThird.setFont(new java.awt.Font("宋体", Font.PLAIN, 16));
lblThird.setText("第二个数");
lblThird.setBounds(new Rectangle(56, 91, 93, 34));
txtFirst.setBounds(new Rectangle(176, 28, 118, 34));
txtThird.setBounds(new Rectangle(176, 86, 118, 34));
lblFifth.setText("结果");
lblFifth.setBounds(new Rectangle(91, 202, 57, 34));
lblFifth.setFont(new java.awt.Font("宋体", Font.PLAIN, 18));
txtForth.setBounds(new Rectangle(179, 202, 135, 34));
btn1.setBounds(new Rectangle(36, 158, 49, 23));
btn1.setText("+");
btn1.addActionListener(new JsqFrame_btn1_actionAdapter(this));
btn2.setBounds(new Rectangle(112, 157, 48, 23));
btn2.setText("-");
btn2.addActionListener(new JsqFrame_jButton2_actionAdapter(this));
btn3.setBounds(new Rectangle(201, 158, 44, 23));
btn3.setText("*");
btn3.addActionListener(new JsqFrame_btn3_actionAdapter(this));
btn4.setBounds(new Rectangle(286, 158, 48, 23));
btn4.setText("/");
btn4.addActionListener(new JsqFrame_btn4_actionAdapter(this));
contentPane.add(lblFirst, null);
contentPane.add(txtFirst);
contentPane.add(txtThird);
contentPane.add(lblThird);
contentPane.add(btn1);
contentPane.add(btn2);
contentPane.add(btn4);
contentPane.add(btn3);
contentPane.add(txtForth);
contentPane.add(lblFifth);
}

public void btnFirst_actionPerformed(ActionEvent e) {

}

public void jButton2_actionPerformed(ActionEvent e) {
float a,b,c=0;
String m;
a = Integer.parseInt(txtFirst.getText());
b = Integer.parseInt(txtThird.getText());
c = a - b;
m = ""+c;
txtForth.setText(m);

}

public void btn1_actionPerformed(ActionEvent e) {
float a,b,c=0;
String m;
a = Integer.parseInt(txtFirst.getText());
b = Integer.parseInt(txtThird.getText());
c =a + b;
m = ""+c;
txtForth.setText(m);
}

public void btn4_actionPerformed(ActionEvent e) {
float a,b,c=0;
String m;
a = Integer.parseInt(txtFirst.getText());
b = Integer.parseInt(txtThird.getText());
c = a/b;
m = ""+c;
txtForth.setText(m);
}

public void btn3_actionPerformed(ActionEvent e) {
float a,b,c=0;
String m;
a = Integer.parseInt(txtFirst.getText());
b = Integer.parseInt(txtThird.getText());
c = a*b;
m = ""+c;
txtForth.setText(m);
}
}

class JsqFrame_btn3_actionAdapter implements ActionListener {
private JsqFrame adaptee;
JsqFrame_btn3_actionAdapter(JsqFrame adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.btn3_actionPerformed(e);
}
}

class JsqFrame_btn4_actionAdapter implements ActionListener {
private JsqFrame adaptee;
JsqFrame_btn4_actionAdapter(JsqFrame adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.btn4_actionPerformed(e);
}
}

class JsqFrame_btn1_actionAdapter implements ActionListener {
private JsqFrame adaptee;
JsqFrame_btn1_actionAdapter(JsqFrame adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.btn1_actionPerformed(e);
}
}

class JsqFrame_jButton2_actionAdapter implements ActionListener {
private JsqFrame adaptee;
JsqFrame_jButton2_actionAdapter(JsqFrame adaptee) {
this.adaptee = adaptee;
}

public void actionPerformed(ActionEvent e) {
adaptee.jButton2_actionPerformed(e);
}
}

Answer 3

唉。。。k！
我的电脑有点问题！要不帮你做一做！
看吧！如果你的问题今天还没解决--我帮你！
电脑的问题我得弄会----看情况吧！估计晚上就好了--最迟明天！
楼主不着急把？

呵呵，今天晚上试一试！好久没做Java了。
最好你把你的一个邮箱告诉我，我把代码发过去！

我了个大概：
http://hi.baidu.com/solzmice/blog/item/681fdc3f4deeeec07c1e7170.html
楼住去看看吧 ！
你可以自己设置，改改，嘿嘿！

Answer 4

APPLET 现在还有人用么?

Answer 5

编写一个Java小应用程序，设计4个按钮，分别命名为“加”、“差”、“积”、“除”以及3个文本框。单击相应的按钮，两个文本框的数字做算术运算，在第3个文本框中显示结果。要求处理NumberFormatException。
我也不知道诶~~~~~~~~。。。。。。。。