javaSwing 计算器代码

package yjq.com.cn;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.ArrayList;
import java.util.EmptyStackException;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.event.MenuEvent;
import javax.swing.event.MenuListener;
public class MyCaculator implements MenuListener, ActionListener {
 JPanel mainp,p1,p2,p3,p4;
 JTextField jt1;
 JMenuItem mnuCopy;
 JMenuItem mnuPaste;
 JButton bM;
 
 boolean isDouble = false;// 是否为实数
 double op1 = 0, op2 = 0;// 操作数1，操作数2
 double n3;
 boolean op2IsEmpty = true;
 boolean op1IsEmpty = true;
 MyStack<Integer> opPool = new MyStack<Integer>();//操作符堆栈
 
 StringBuffer buf = new StringBuffer(20);
 StringBuffer copyBoard = new StringBuffer(20);// 剪贴板
 StringBuffer memory = new StringBuffer(20);// M系列
 StringBuffer str = new StringBuffer();//缓冲器
 
 public MyCaculator()
  {   
  p1=new JPanel();
  p1.setLayout(new GridLayout(2,1,10,10));
  JMenuBar mnuNotepad=new JMenuBar();
  JMenu mnuEdit=new JMenu("编辑(E)");
  mnuEdit.setMnemonic(KeyEvent.VK_E);
  JMenu mnuCheck=new JMenu("查看(V)");
  mnuCheck.setMnemonic(KeyEvent.VK_V);
  JMenu mnuHelp=new JMenu("帮助(H)");
  mnuCopy=new JMenuItem("复制(C)");
  mnuPaste=new JMenuItem("粘贴(P)");
     JMenuItem mnuVisit=new JMenuItem("查看帮助(V)");
     JMenuItem mnuAbout=new JMenuItem("关于计算器(A)");
     
     JSeparator sep=new JSeparator();
     jt1=new JTextField("0.");
  jt1.setHorizontalAlignment(JTextField.RIGHT);
  
  jt1.setSelectedTextColor(Color.yellow);
  jt1.setEditable(true);
  
  mnuEdit.addMenuListener(this);
  mnuCheck.addMenuListener(this);
  mnuHelp.addMenuListener(this);
  mnuCopy.addActionListener(this);
  mnuPaste.addActionListener(this);
  mnuVisit.addActionListener(this);
  mnuAbout.addActionListener(this);
  mnuNotepad.add(mnuEdit);
  mnuNotepad.add(mnuCheck);
  mnuNotepad.add(mnuHelp);
  mnuEdit.add(mnuCopy);
  mnuEdit.add(mnuPaste);
  mnuEdit.add(sep);
  mnuHelp.add(mnuVisit);
  mnuHelp.add(sep);
  mnuHelp.add(mnuAbout);
  p1.add(mnuNotepad);
  p1.add(jt1);
  p2=new JPanel();
  p2.setLayout(new FlowLayout(FlowLayout.CENTER));
  bM = new JButton(" ");
  bM.setEnabled(false);
  p2.add(bM);
  JButton b25=new JButton("Backspace");
  b25.addActionListener(this);
  JButton b26=new JButton("CE");
  b26.addActionListener(this);
  JButton b27=new JButton("C");
  b27.addActionListener(this);
  p2.add(b25);
  p2.add(b26);
  p2.add(b27);
  p3=new JPanel();
  p3.setLayout(new GridLayout(4,6));
  
  JButton button1=new JButton("MC");
  button1.addActionListener(this);
  JButton button2=new JButton("7");
  button2.addActionListener(this);
  JButton button3=new JButton("8");
  button3.addActionListener(this);
  JButton button4=new JButton("9");
  button4.addActionListener(this);
  JButton button5=new JButton("/");
  button5.addActionListener(this);
  JButton button6=new JButton("sqrt");
  button6.addActionListener(this);
  JButton button7=new JButton("MR");
  button7.addActionListener(this);
  JButton button8=new JButton("4");
  button8.addActionListener(this);
  JButton button9=new JButton("5");
  button9.addActionListener(this);
  JButton button10=new JButton("6");
  button10.addActionListener(this);
  JButton button11=new JButton("*");
  button11.addActionListener(this);
  JButton button12=new JButton("%");
  button12.addActionListener(this);
  JButton button13=new JButton("MS");
  button13.addActionListener(this);
  JButton button14=new JButton("1");
  button14.addActionListener(this);
  JButton button15=new JButton("2");
  button15.addActionListener(this);
  JButton button16=new JButton("3");
  button16.addActionListener(this);
  JButton button17=new JButton("-");
  button17.addActionListener(this);
  JButton button18=new JButton("1/x");
  button18.addActionListener(this);
  JButton button19=new JButton("M+");
  button19.addActionListener(this);
  JButton button20=new JButton("0");
  button20.addActionListener(this);
  JButton button21=new JButton("+/-");
  button21.addActionListener(this);
  JButton button22=new JButton(".");
  button22.addActionListener(this);
  JButton button23=new JButton("+");
  button23.addActionListener(this);
  JButton button24=new JButton("=");
  button24.addActionListener(this);
  p3.add(button1);p3.add(button2);
  p3.add(button3);p3.add(button4);
  p3.add(button5);p3.add(button6);
  p3.add(button7);p3.add(button8);
  p3.add(button9);p3.add(button10);
  p3.add(button11);p3.add(button12);
  p3.add(button13);p3.add(button14);
  p3.add(button15);p3.add(button16);
  p3.add(button17);p3.add(button18);
  p3.add(button19);p3.add(button20);
  p3.add(button21);p3.add(button22);
  p3.add(button23);p3.add(button24);
  p3.setSize(250,250);
  mainp=new JPanel();
  mainp.setLayout(new GridLayout(3,1));
  mainp.add(p1);
  mainp.add(p2);
  mainp.add(p3);
  
  JFrame f = new JFrame();
  f.getContentPane().add(mainp);
  f.setTitle("计算器");
  f.setSize(350,350);
  f.setVisible(true);
  f.addWindowListener(new WindowAdapter(){
   public void windowClosing(WindowEvent e){
    System.exit(0);
   }});
 }
public void menuCanceled(MenuEvent e) {
}
public void menuDeselected(MenuEvent e) {
}
public void menuSelected(MenuEvent e) {
}
 public void actionPerformed(ActionEvent e) {
  String s= e.getActionCommand();
  
  if(s.equals("复制(C)")){
   String temp = jt1.getText().trim();  
   copyBoard.replace(0, copyBoard.length(), temp);
  }
  
  else if(s.equals("粘贴(P)")){
   jt1.setText(copyBoard.toString());  
  }
  
  else if(s.equals("查看帮助(V)")){
   
  }
  
  else if(s.equals("关于计算器(A)")){
   JOptionPane.showMessageDialog(null, "designed by YJQ!");
  }
  
  else if(s.equals("Backspace")){
   if (!jt1.getText().trim().equals("0.")) {
    // 如果文本框中有内容
    str.setLength(0);
    str.append(jt1.getText().trim());
    if (str.length() != 1 && str.length() != 0) {
     str.setLength(str.length() - 1);
     jt1.setText(str.toString());
    } 
    else {
     jt1.setText("0.");
     str.setLength(0);
    }
   }
  }
  else if(s.equals("CE")){
   jt1.setText("0.");
  }
  else if(s.equals("C")){
   isDouble = false;
   jt1.setText("0.");
   op1 = op2 = 0;
   str.replace(0,str.length(),"");
   opPool.clear();
   op2IsEmpty = true;
   op1IsEmpty = true;
  }
  else if(s.equals("MC")){
   // 如果是MC则清除缓冲区
   memory.setLength(0);
   bM.setText(" "); 
  }
  else if(s.equals("MR")){
   // 如果按键为MR则恢复缓冲区的数到文本框
   jt1.setText(memory.toString());
  }
  else if(s.equals("MS")){
  // 如果按键为MS则将文本框的数存入缓冲区
   try{
    n3 = Double.parseDouble(jt1.getText().trim());
    memory.setLength(0);
    memory.append(n3);
    bM.setText("M");
   }
   catch(Exception ex){
    ex.printStackTrace();
    JOptionPane.showMessageDialog(null, "文本不是实数，不能被存储！");
   };
  }
  
  else if(s.equals("M+")){
   // 如果按键为MS则将文本框值与缓冲区的数相加但不显示结果
   String temp1 = jt1.getText().trim();
   double dtemp = Double.parseDouble(temp1);
   String temp2 = memory.toString();
   dtemp += Double.parseDouble(temp2);
   temp1 = String.valueOf(dtemp);
   memory.replace(0, memory.length(), temp1);   
   
  }
  else if(s.equals("sqrt")){
   String temp = jt1.getText().trim();
   double dtemp = Double.parseDouble(temp);
   if(dtemp >= 0){
    jt1.setText("" + Math.sqrt(dtemp));
    str.setLength(0);
    str.append(jt1.getText().trim());
    op2 = Double.parseDouble(jt1.getText().trim());
    op1 = op2;
    op1IsEmpty = false;
    op2IsEmpty = true;
   }
   else{
    JOptionPane.showMessageDialog(null, "sqrt的操作数不能为负数");
   };
  }
  
  else if(s.equals("+/-")){
   op2 = Double.parseDouble(jt1.getText().trim());
   if(op1IsEmpty) {
    op1 = -op2;
    op1IsEmpty = false;
    op2 = 0;
    op2IsEmpty = true;
    jt1.setText("" + op1);
   }
   else{
    op2 = -op2;
    jt1.setText("" + op2);
    
   }
  }
  
  else if(s.equals("%")){
   if(isDouble){
   n3 = Double.parseDouble(jt1.getText().trim())*100;
   jt1.setText(""+n3+"%");
   }
  }
  
  else if(s.equals("1/x")){
   String temp = jt1.getText().trim();
   double dtemp = Double.parseDouble(temp);
   op2 = dtemp;
   if(op2 != 0){
    op2 = 1/op2;
    str.setLength(0);
    str.append("" + op2);
    jt1.setText(str.toString());
    op1 = op2;
    op2IsEmpty = true;
   }
   else{
    JOptionPane.showMessageDialog(null, "1/x的操作数不能为0");
   }
  }
  
  else if(s.equals("+")){
   if(op1IsEmpty) {
    op1 = op2;
    op1IsEmpty = false;
    op2IsEmpty = true;
   }
   if (opPool.isEmpty()||op2IsEmpty){
    opPool.clear();
    opPool.push(1);
    jt1.setText("" + op1);
   }
   else {
    switch (opPool.pop()) {
    case 1:
     op1 += op2;
     jt1.setText("" + op1);
     
     break;
    case 2:
     op1 -= op2;
     jt1.setText("" + op1);
     break;
    case 3:
     op1 *= op2;
     jt1.setText("" + op1);
     break;
    case 4:
     if(op2 != 0) op1 /= op2;
     else JOptionPane.showMessageDialog(null, "除数不能为0");
     jt1.setText("" + op1);
     break;
    }
    opPool.push(1);
    op2IsEmpty= true;
   }
   str.setLength(0);
  }
  else if(s.equals("-")){
   if(op1IsEmpty&&!op2IsEmpty) {
    op1 = op2;
    op1IsEmpty = false;
    op2 = 0;
    op2IsEmpty = true;
   }
   if (opPool.isEmpty()||op2IsEmpty){
    opPool.clear();
    opPool.push(2);
    jt1.setText("" + op1);
   }
   else {
    switch (opPool.pop()) {
    case 1:
     op1 += op2;
     jt1.setText("" + op1);
     
     break;
    case 2:
     op1 -= op2;
     jt1.setText("" + op1);
     break;
    case 3:
     op1 *= op2;
     jt1.setText("" + op1);
     break;
    case 4:
     if(op2 != 0) op1 /= op2;
     else JOptionPane.showMessageDialog(null, "除数不能为0");
     jt1.setText("" + op1);
     break;
    }
    opPool.push(2);
    op2 = 0;
    op2IsEmpty = true;
   }
   str.setLength(0);
  }
  else if(s.equals("*")){
   if(op1IsEmpty&&!op2IsEmpty) {
    op1 = op2;
    op1IsEmpty = false;
    op2 = 0;
    op2IsEmpty = true;
   }
   str.setLength(0);
   if (opPool.isEmpty()||op2IsEmpty){
    opPool.clear();
    opPool.push(3);
    jt1.setText("" + op1);
   }
   else {
    switch (opPool.pop()) {
    case 1:
     op1 += op2;
     jt1.setText("" + op1);
     
     break;
    case 2:
     op1 -= op2;
     jt1.setText("" + op1);
     break;
    case 3:
     op1 *= op2;
     jt1.setText("" + op1);
     break;
    case 4:
     if(op2 != 0) op1 /= op2;
     else JOptionPane.showMessageDialog(null, "除数不能为0");
     jt1.setText("" + op1);
     break;
    }
    opPool.push(3);
    op2 = 0;
    op2IsEmpty = true;
   }
   str.setLength(0);
  }
  else if(s.equals("/")){
   if(op1IsEmpty&&!op2IsEmpty) {
    op1 = op2;
    op1IsEmpty = false;
    op2 = 0;
    op2IsEmpty = true;
   }
   
   if (opPool.isEmpty()||op2IsEmpty){
    opPool.clear();
    opPool.push(4);
    jt1.setText("" + op1);
   }
   else {
    switch (opPool.pop()) {
    case 1:
     op1 += op2;
     jt1.setText("" + op1);
     
     break;
    case 2:
     op1 -= op2;
     jt1.setText("" + op1);
     break;
    case 3:
     op1 *= op2;
     jt1.setText("" + op1);
     break;
    case 4:
     if(op2 != 0) op1 /= op2;
     else JOptionPane.showMessageDialog(null, "除数不能为0");
     jt1.setText("" + op1);
     break;
    }
    opPool.push(4);
    op2IsEmpty = true;
   }
   str.setLength(0);
  }
  else if(s.equals(".")){
   if(jt1.getText().trim().indexOf(".") == -1 ){
     str.append(s);
     jt1.setText(str.toString());
   }
   isDouble = true;
  }
  
  else if(s.equals("=")){
   if(op1IsEmpty&&!op2IsEmpty) {
    op1 = op2;
    op1IsEmpty = false;
    op2 = 0;
    op2IsEmpty = true;
   }
   if (opPool.isEmpty()||op2IsEmpty){
    opPool.clear();
    jt1.setText("" + op1);
   }
   else {
    switch (opPool.pop()) {
    case 1:
     op1 += op2;
     jt1.setText("" + op1);
     
     break;
    case 2:
     op1 -= op2;
     jt1.setText("" + op1);
     break;
    case 3:
     op1 *= op2;
     jt1.setText("" + op1);
     break;
    case 4:
     if(op2 != 0) op1 /= op2;
     else JOptionPane.showMessageDialog(null, "除数不能为0");
     jt1.setText("" + op1);
     break;
    }
    op2 = 0;
    op2IsEmpty = true;
   }
   str.setLength(0);
  }
  
  else if (s.equals("0")){  // 如果选择的是"0"这个数字键
   if (jt1.getText().trim().equals("0.")) {
    str.replace(0,str.length(),"0.");
    if(isDouble){ //为浮点数时  0加到   str 中去
     jt1.setText(str.append(s).toString());
     op2 = Double.parseDouble(str.toString().trim());
     op2IsEmpty = false;
    }
    else{
    }
   } 
   else { 
    jt1.setText(str.append(s).toString());
    op2 = Double.parseDouble(str.toString().trim());
    op2IsEmpty = false;
   }
  }
  
  else{
   jt1.setText(str.append(s).toString());
   op2 = Double.parseDouble(str.toString().trim());
   op2IsEmpty = false;
  }
 }
 public static void main(String args[]){
  new MyCaculator();
 }
}
class MyStack<Object>{
 private List<Object> pool= new ArrayList<Object>();
 
 public MyStack(){
  
 }
 
 public void clear() {   
  pool.clear();   
 } 
 
 public boolean isEmpty(){
  return pool.isEmpty();   
 }
 /**  
  * 获取栈顶元素
  * */
 public Object  getTopObjcet() {
  if (isEmpty()) {return null;}
  return pool.get(0);
  
 }
 /**  
  * 弹出栈操作  
  * */
 public Object pop(){
   if (isEmpty()) {throw new EmptyStackException();} 
   return pool.remove(pool.size() - 1);
 }
 
 /**  
  * 压入栈操作  
  * */
 public void push(Object i){
  pool.add(i);
 }
 /**  
 * 获取当前栈大小  
 * */  
 public int getStackSize(){
  if (isEmpty()) {throw new EmptyStackException();}
  return pool.size();
 }
}