在此我把源代码整个贴上来，有利于初学者学习哦。
//标准型计算器
package standardCalculator;
import java.awt.*;
import java.awt.event.*;
import java.awt.datatransfer.*;
import java.util.*;
import java.io.*;
import javax.swing.*;
import java.text.*;
public class Calculator1 extends JPanel implements ClipboardOwner{
// declarations of all used components
public JFrame theFrame;
public JLabel memoryLabel;
public JMenuBar theMenuBar;
public JMenu editMenu;
public JMenuItem copyMenuItem, pasteMenuItem;
public JMenu viewMenu;
public ButtonGroup styleButtonGroup;
public JRadioButtonMenuItem staRBMenuItem, sciRBMenuItem;
public JCheckBoxMenuItem chooseNumberGroup;
public JMenu helpMenu;
public JMenuItem helpMenuItem, aboutMenuItem;
public ActionListener copyListener, pasteListener;
public ActionListener styleListener, chooseListener;
public ActionListener helpListener, aboutListener;
public ActionListener buttonListener;
public JTextField theTextField;
public GridBagConstraints gbc;
public Clipboard clipboard = getToolkit().getSystemClipboard();
public int flagSTART = 1;
public int flagCE = 0;
public Double memoryStore = new Double(0);
public double result = 0;
String operator = "NULL";
public String theDisplay = new String();
public Calculator1(){
}
public Calculator1(boolean on){
gbc = new GridBagConstraints();
// creating the JFrame, JMenuBar, JTextField, JPanel
theFrame = new JFrame("Calculator");
theMenuBar = new JMenuBar();
theTextField = new JTextField();
theTextField.setHorizontalAlignment(JTextField.RIGHT);
theTextField.setText("0.");
// creating the menus and menu items
editMenu = new JMenu("Edit");
copyMenuItem = new JMenuItem("Copy");
pasteMenuItem = new JMenuItem("Paste");
pasteMenuItem.setEnabled(false);
//===============================================================
viewMenu = new JMenu("View");
styleButtonGroup = new ButtonGroup();
staRBMenuItem = new JRadioButtonMenuItem("Standard");
sciRBMenuItem = new JRadioButtonMenuItem("Scientific", true);
styleButtonGroup.add(staRBMenuItem);
styleButtonGroup.add(sciRBMenuItem);
//---------------------------------------------------------------
chooseNumberGroup = new JCheckBoxMenuItem("NumberGroup");
//===============================================================
helpMenu = new JMenu("Help");
helpMenuItem = new JMenuItem("Help Contents...");
aboutMenuItem = new JMenuItem("About Calculator...");
// creating JLabel
memoryLabel = new JLabel("");
memoryLabel.setBorder(BorderFactory.createBevelBorder(1));
// creating the action listeners
copyListener = new CopyListener();
pasteListener = new PasteListener();
//===============================================================
styleListener = new StyleListener();
//---------------------------------------------------------------
chooseListener = new ChooseListener();
//===============================================================
helpListener = new HelpListener();
aboutListener = new AboutListener();
//===============================================================
buttonListener = new ButtonListener();
// connecting components to the action listeners
copyMenuItem.addActionListener(copyListener);
pasteMenuItem.addActionListener(pasteListener);
//===============================================================
staRBMenuItem.addActionListener(styleListener);
sciRBMenuItem.addActionListener(styleListener);
//---------------------------------------------------------------
chooseNumberGroup.addActionListener(chooseListener);
//===============================================================
helpMenuItem.addActionListener(helpListener);
aboutMenuItem.addActionListener(aboutListener);
//===============================================================
ContainerListener listener = new ContainerAdapter() {
public void componentAdded(ContainerEvent e) {
Component comp = e.getChild();
if (comp instanceof JButton) ((JButton)comp).addActionListener(buttonListener);
}
};
addContainerListener(listener);
// creating Mnemonics for MenuItems and RadioButtonMenuItems
editMenu.setMnemonic(KeyEvent.VK_E);
copyMenuItem.setMnemonic(KeyEvent.VK_C);
pasteMenuItem.setMnemonic(KeyEvent.VK_P);
//===============================================================
viewMenu.setMnemonic(KeyEvent.VK_V);
staRBMenuItem.setMnemonic(KeyEvent.VK_T);
sciRBMenuItem.setMnemonic(KeyEvent.VK_S);
//---------------------------------------------------------------
chooseNumberGroup.setMnemonic(KeyEvent.VK_G);
//===============================================================
helpMenu.setMnemonic(KeyEvent.VK_H);
helpMenuItem.setMnemonic(KeyEvent.VK_H);
aboutMenuItem.setMnemonic(KeyEvent.VK_A);
// creating Accelerators for MenuItems and RadioButtonMenuItems
copyMenuItem.setAccelerator(KeyStroke.getKeyStroke(
KeyEvent.VK_C, InputEvent.CTRL_MASK, false));
pasteMenuItem.setAccelerator(KeyStroke.getKeyStroke(
KeyEvent.VK_V, InputEvent.CTRL_MASK, false));
// setting tooltips
memoryLabel.setToolTipText("Memory setting flag");
// adding components to menus
editMenu.add(copyMenuItem);
editMenu.add(pasteMenuItem);
//===============================================================
viewMenu.add(staRBMenuItem);
viewMenu.add(sciRBMenuItem);
viewMenu.addSeparator();
//---------------------------------------------------------------
viewMenu.add(chooseNumberGroup);
//===============================================================
helpMenu.add(helpMenuItem);
helpMenu.addSeparator();
helpMenu.add(aboutMenuItem);
// adding menus to JMenuBar
theMenuBar.add(editMenu);
theMenuBar.add(viewMenu);
theMenuBar.add(helpMenu);
// adding components to JFrame
gbc.weightx = 1.0;
gbc.weighty = 1.0;
gbc.fill = GridBagConstraints.BOTH;
gbc.gridwidth = 6;
addGB(this, theMenuBar, 0, 0);
addGB(this, theTextField, 0, 1);
//添加数字JButton
gbc.gridwidth = 1;
for(int row=5; row>2; row--)
for(int column=1; column<4; column++)
addGB(this, new JButton(" "+(15+column-3*row)+" "), column, row);
//添加其它JButton
addGB(this, new JButton("0"), 1, 6);
addGB(this, new JButton("＋／－"), 2, 6);
addGB(this, new JButton("."), 3, 6);
addGB(this, new JButton("＋"), 4, 6);
addGB(this, new JButton("－"), 4, 5);
addGB(this, new JButton("×"), 4, 4);
addGB(this, new JButton("÷"), 4, 3);
addGB(this, new JButton("＝"), 5, 6);
addGB(this, new JButton(" 1／x "), 5, 5);
addGB(this, new JButton("％"), 5, 4);
addGB(this, new JButton("√￣"), 5, 3);
addGB(this, new JButton("C"), 2, 2 );
addGB(this, new JButton("CE"), 3, 2);
gbc.gridwidth = 2;
addGB(this, new JButton("Backspace"), 4, 2);
gbc.gridwidth = 1;
gbc.ipadx = 50;
addGB(this, memoryLabel, 0, 2);
gbc.ipadx = 0;
addGB(this, new JButton("MC"), 0, 3);
addGB(this, new JButton("MR"), 0, 4);
addGB(this, new JButton("MS"), 0, 5);
addGB(this, new JButton("M＋"), 0, 6);
} // end of constructing Calculator1(boolean on)
public void addGB(Container cont, Component comp, int x, int y) {
if ((cont.getLayout() instanceof GridBagLayout) == false)
cont.setLayout(new GridBagLayout());
gbc.gridx = x;
gbc.gridy = y;
cont.add(comp, gbc);
}
class CopyListener implements ActionListener{
public void actionPerformed(ActionEvent e){
copy();
}
}
public void copy(){
String srcData = theTextField.getText();
if(srcData != null){
StringSelection contents = new StringSelection(srcData);
clipboard.setContents(contents, this);
pasteMenuItem.setEnabled(true);
}
}
class PasteListener implements ActionListener{
public void actionPerformed(ActionEvent e){
paste();
}
}
public void paste(){
Transferable content = clipboard.getContents(this);
if(content != null){
try{
String dstData = (String)content.getTransferData(DataFlavor.stringFlavor);
theTextField.setText(dstData);
}catch (Exception e){
System.out.println("Couldn't get contents in format: "+
DataFlavor.stringFlavor.getHumanPresentableName());
}
}
}
class StyleListener implements ActionListener{
public void actionPerformed(ActionEvent e){
}
}
class ChooseListener implements ActionListener{
public void actionPerformed(ActionEvent e){
NumberFormat numberFormat = NumberFormat.getInstance(Locale.getDefault());
if(chooseNumberGroup.getState() == true){
double operand = Double.parseDouble(theDisplay);
((DecimalFormat)numberFormat).setGroupingSize(3);
numberFormat.setGroupingUsed(true);
theTextField.setText(new Double(numberFormat.format(operand)).toString());
}
else numberFormat.setGroupingUsed(false);
}
}
class HelpListener implements ActionListener{
public void actionPerformed(ActionEvent e){
}
}
class AboutListener implements ActionListener{
public void actionPerformed(ActionEvent e){
}
}
class ButtonListener implements ActionListener{
public void actionPerformed(ActionEvent e){
if(e.getActionCommand().trim().equals("C")){
theDisplay = "0.";
theTextField.setText(theDisplay);
result = 0;
flagSTART = 1;
return;
}
else if(e.getActionCommand().trim().equals("CE")){
flagCE = 1;
theDisplay = "0.";
theTextField.setText(theDisplay);
flagSTART = 1;
return;
}
else if(e.getActionCommand().trim().equals("Backspace")){
int lengeth = theDisplay.length();
if(lengeth > 1){
theTextField.setText(theDisplay.substring(0,lengeth-1));
return;
}
theTextField.setText("");
return;
}
else if(e.getActionCommand().trim().equals("MS")){
memoryLabel.setText("M");
memoryLabel.setVerticalAlignment(JLabel.CENTER);
memoryLabel.setHorizontalAlignment(JLabel.CENTER);
memoryStore = Double.valueOf(theDisplay);
return;
}
else if(e.getActionCommand().trim().equals("MC")){
memoryLabel.setText("");
memoryStore = new Double(0);
return;
}
else if(e.getActionCommand().trim().equals("MR")){
theDisplay = memoryStore.toString();
theTextField.setText(theDisplay);
return;
}
else if(e.getActionCommand().trim().equals("M＋")){
memoryStore = new Double(memoryStore.doubleValue()
+ Double.parseDouble(theDisplay));
return;
}
else if(e.getActionCommand().trim().equals("＋／－")){
theDisplay = new Double(0.0 - Double.parseDouble(theDisplay)).toString();
theTextField.setText(theDisplay);
return;
}
else if(e.getActionCommand().trim().equals("1／x")){
theDisplay = new Double(1.0 / Double.parseDouble(theDisplay)).toString();
theTextField.setText(theDisplay);
return;
}
else if(e.getActionCommand().trim().equals("√￣")){
theDisplay = new Double(Math.sqrt(Double.parseDouble(theDisplay))).toString();
theTextField.setText(theDisplay);
return;
}
else if(e.getActionCommand().trim().equals("％")){
theDisplay = new Double(Double.parseDouble(theDisplay) / 100.0).toString();
theTextField.setText(theDisplay);
return;
}
else if(!isOperator(e.getActionCommand().trim())){
if(flagSTART == 1){
flagCE = 0;
theDisplay = e.getActionCommand().trim();
theTextField.setText(theDisplay);
flagSTART = 0;
return;
}
theDisplay = theDisplay + e.getActionCommand().trim();
theTextField.setText(theDisplay);
return;
}
// is operator
if(flagCE == 1){
flagCE = 0;
operator = e.getActionCommand().trim();
return;
}
else if(operator.equals("NULL")||operator.equals("＝")){
result = Double.parseDouble(theDisplay);
}
else if(operator.equals("＋")){
result = result + Double.parseDouble(theDisplay);
}
else if(operator.equals("－")){
result = result - Double.parseDouble(theDisplay);
}
else if(operator.equals("×")){
result = result * Double.parseDouble(theDisplay);
}
else if(operator.equals("÷")){
result = result / Double.parseDouble(theDisplay);
}
flagSTART = 1;
operator = e.getActionCommand().trim();
theDisplay = new Double(result).toString();
theTextField.setText(theDisplay);
return;
}
}
boolean isOperator(String operator){
if(operator.equals("＋")||operator.equals("－")||operator.equals("×")
||operator.equals("÷")||operator.equals("＝")) return true;
else return false;
}
public void lostOwnership(Clipboard clipboard, Transferable contents){
System.out.println("Clipboard contents replaced");
}
private void launchFrame(){
//JFrame theFrame = new JFrame("Calculator");
theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
theFrame.setSize(420,220);
theFrame.setLocation(100,100);
theFrame.setContentPane(new Calculator1(true));
theFrame.setVisible(true);
}
public static void main(String[] args){
Calculator1 calculator1 = new Calculator1(true);
calculator1.launchFrame();
}
}