java编一个计算器的代码

JAVA 编写计算器 要代码最简单的~

学java的时候自己编的，很简单，能够连续输入计算式后进行计算
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.NumberFormat;
import java.util.ArrayList;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
/**简易计算器，能够进行简单的计算
*
* @see 2008.12.9
*/
public class CalculatorA
implements ActionListener{

private JFrame frame;
private JTextField field;
private JButton[] allButtons;
private JButton clearButton;
// private JButton backButton;
String result="";//保存结果
StringBuilder sb = new StringBuilder();//保存要进行的计算式
int x = 0; //用来判断上一次的事件类型
String str = "123+456-789*0.=/";
ArrayList arrayList = new ArrayList();//保存计算式，通过方法进行运算

public CalculatorA(){

frame = new JFrame("我的计算器v1.1");
frame.setLocation(300,300);

field = new JTextField(25);

allButtons = new JButton[16];
for(int i=0;i<allButtons.length;i++){
allButtons[i]= new JButton(str.substring(i,i+1));
}
clearButton = new JButton("CLEAR");
// backButton = new JButton("<——");

init();
setFondAndColor();
addEventHander();
}

public void init(){
frame.setLayout(new BorderLayout());

JPanel northPanel = new JPanel();
JPanel centerPanel = new JPanel();
JPanel southPanel = new JPanel();

northPanel.setLayout(new FlowLayout());
centerPanel.setLayout(new GridLayout(4,4));
southPanel.setLayout(new FlowLayout());

northPanel.add(field);
for(int i=0;i<allButtons.length;i++){
centerPanel.add(allButtons[i]);
}
southPanel.add(clearButton);
//southPanel.add(backButton);

frame.add(northPanel,BorderLayout.NORTH);
frame.add(centerPanel,BorderLayout.CENTER);
frame.add(southPanel,BorderLayout.SOUTH);
}
//设置输入字体
public void setFondAndColor(){
field.setFont(new Font("宋体",Font.BOLD,24));
field.setBackground(new Color(100,200,200));
field.setForeground(Color.RED);
//设置字体从右起始
field.setHorizontalAlignment(JTextField.RIGHT);
}

public void showMi(){
frame.pack();
frame.setResizable(false);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public void addEventHander(){
for(int i=0;i<allButtons.length;i++){
allButtons[i].addActionListener(this);
}
clearButton.addActionListener(this);
// backButton.addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
String str = e.getActionCommand();//取得当前事件返回的值
if("0123456789.".indexOf(str)!=-1){
if(x == 0){ //当x为0时表示还没有进行输入
result=str;
sb.append(str);
field.setText(str);
x = 1;
}
else if(x == 1){
result = result +str;
sb.append(str);
field.setText(result);
x = 1;
}
else if(x == 2){
sb.delete(0,sb.length());
result = result+str;
sb.append(str);
field.setText(result);
x = 1;
}
else if(x == 3){
result = str;
sb.delete(0,sb.length());
arrayList.clear();
field.setText(str);
sb.append(str);
field.setText(str);
x = 1;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
result = str;
sb.append(str);
field.setText(str);
x = 1;
}
else{
result = result +str;
sb.append(str);
field.setText(result);
x = 1;
}
}
else if("+*-/".indexOf(str)!=-1){
if(x == 0){
field.setText("");
x = 2;
}
else if(x == 1){
result = result + str;
arrayList.add(sb.toString());
arrayList.add(str);
sb.append(str);
field.setText(result);
x = 2;
}
else if(x == 2){
x = 2;
}
else if(x == 3){
field.setText(result+str);
arrayList.add(result);
arrayList.add(str);
result = result+str;
x = 2;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
x = 2;
}
else{
field.setText(result+str);
arrayList.add(result);
arrayList.add(str);
result = result+str;
x = 2;
}
}
else if("=".equals(str)){
if(x == 0){
field.setText("0");
arrayList.clear();
result = "0";
x = 3;
}
else if(x == 1){
try{
arrayList.add(sb.toString());
arrayList = getResult(arrayList);
result = arrayList.get(0);
field.setText(result);
arrayList.clear();
x = 3;
}catch(Exception e1){
field.setText("数据格式异常");
x = 0;
}
}
else if(x == 2){
field.setText("数据格式错误.....");
arrayList.clear();
x = 0;
}
else if(x == 3){
field.setText(result);
x = 3;
}
else if(x == 4){
result ="";
sb.delete(0,sb.length());
arrayList.clear();
x = 3;
}
else {
try{
arrayList.add(sb.toString());
arrayList = getResult(arrayList);
result = arrayList.get(0);
field.setText(result);
arrayList.clear();
x = 3;
}catch(Exception e1){
field.setText("数据格式异常");
x = 0;
}
}
}
else if("CLEAR".equals(str)){
arrayList.clear();
field.setText("0");
arrayList.add("0");
x = 4;
}
else{
if(result.length()>1){
result = result.substring(0,result.length()-1);
if(sb.length()>0){
sb.delete(sb.length()-1,sb.length());
}
else {
sb.delete(0,1);
}
field.setText(result);
x = 5;
}
else{
result = "";
sb.delete(0,sb.length());
arrayList.clear();
field.setText("0");
x = 0;
}
}
}
public static ArrayList getResult(ArrayList list){
String res = null;
String[] s = {"/","*","-","+"};
int i=0;
if(list.size()>1){
for(;i<s.length;){
if(s[i].equals("/")){
for(int j=0;j<list.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))/Double.parseDouble(list.get(j+1)));
//本地的数据格式
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else if(s[i].equals("*")){
for(int j=0;j<list.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))*Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else if(s[i].equals("-")){
for(int j=0;j<list.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))-Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getNumberInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
else {
for(int j=0;j<list.size();j++){
if(list.get(j).equals(s[i])){
res = Double.toString(Double.parseDouble(list.get(j-1))+Double.parseDouble(list.get(j+1)));
NumberFormat nf = NumberFormat.getInstance();
res = nf.format(Double.parseDouble(res));
res = getChange(res);
list.set(j-1,res);
list.remove(j);
list.remove(j);
getResult(list);
}
}
i++;
}
}
}
return list;
}
//对数字字符串进行排除不必要符号
public static String getChange(String res){
String s_temp = "";
char[] c = new char[res.length()];
for(int k=0;k<c.length;k++){
c[k] = res.charAt(k);
}
for(int k=0;k<c.length;k++){
if((c[k]>= '0' && c[k]<= '9')|| c[k] == '.'){
s_temp += c[k];
}
}
return s_temp;
}
public static void main(String[] args){
new CalculatorA().showMi();
}
}

下面，将此Java程序分享一下（详细描述见注释）：
/*
* @(#)JCalculator.java 1.00 12/29/2009
*
* Email: light_warm@163.com
*/

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

/**
* A simple calculator program.
* I saw this program in a QQ group, and help a friend correct it.
*
* @author Singyuen Yip
* @version 1.00 12/29/2009
* @see JFrame
* @see ActionListener
*/
public class JCalculator extends JFrame implements ActionListener {
/**
* Serial Version UID
*/
private static final long serialVersionUID = -169068472193786457L;
/**
* This class help close the Window.
* @author Singyuen Yip
*
*/
private class WindowCloser extends WindowAdapter {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
}

int i;
// Strings for Digit & Operator buttons.
private final String[] str = { "7", "8", "9", "/", "4", "5", "6", "*","1",
"2", "3", "-", ".", "0", "=", "+" };
// Build buttons.
JButton[] buttons = new JButton[str.length];
// For cancel or reset.
JButton reset = new JButton("CE");
// Build the text field to show the result.
JTextField display = new JTextField("0");

/**
* Constructor without parameters.
*/
public JCalculator() {
super("Calculator");
// Add a panel.
JPanel panel1 = new JPanel(new GridLayout(4, 4));
// panel1.setLayout(new GridLayout(4,4));
for (i = 0; i < str.length; i++) {
buttons[i] = new JButton(str[i]);
panel1.add(buttons[i]);
}
JPanel panel2 = new JPanel(new BorderLayout());
// panel2.setLayout(new BorderLayout());
panel2.add("Center", display);
panel2.add("East", reset);
// JPanel panel3 = new Panel();
getContentPane().setLayout(new BorderLayout());
getContentPane().add("North", panel2);
getContentPane().add("Center", panel1);
// Add action listener for each digit & operator button.
for (i = 0; i < str.length; i++)
buttons[i].addActionListener(this);
// Add listener for "reset" button.
reset.addActionListener(this);
// Add listener for "display" button.
display.addActionListener(this);
// The "close" button "X".
addWindowListener(new WindowCloser());
// Initialize the window size.
setSize(800, 800);
// Show the window.
// show(); Using show() while JDK version is below 1.5.
setVisible(true);
// Fit the certain size.
pack();
}

public void actionPerformed(ActionEvent e) {
Object target = e.getSource();
String label = e.getActionCommand();
if (target == reset)
handleReset();
else if ("0123456789.".indexOf(label) > 0)
handleNumber(label);
else
handleOperator(label);
}
// Is the first digit pressed?
boolean isFirstDigit = true;
/**
* Number handling.
* @param key the key of the button.
*/
public void handleNumber(String key) {
if (isFirstDigit)
display.setText(key);
else if ((key.equals(".")) && (display.getText().indexOf(".") < 0))
display.setText(display.getText() + ".");
else if (!key.equals("."))
display.setText(display.getText() + key);
isFirstDigit = false;
}

/**
* Reset the calculator.
*/
public void handleReset() {
display.setText("0");
isFirstDigit = true;
operator = "=";
}

double number = 0.0;
String operator = "=";

/**
* Handling the operation.
* @param key pressed operator's key.
*/
public void handleOperator(String key) {
if (operator.equals("+"))
number += Double.valueOf(display.getText());
else if (operator.equals("-"))
number -= Double.valueOf(display.getText());
else if (operator.equals("*"))
number *= Double.valueOf(display.getText());
else if (operator.equals("/"))
number /= Double.valueOf(display.getText());
else if (operator.equals("="))
number = Double.valueOf(display.getText());
display.setText(String.valueOf(number));
operator = key;
isFirstDigit = true;
}

public static void main(String[] args) {
new JCalculator();
}
}

界面漂亮堪比系统自带计算器，功能完美加减乘除开平方等等全部具备，还有清零按钮，小数点的使用，连加连乘功能完全参考系统官方计算器经过长期调试改进而成，马上拷贝代码拿去试试看吧，绝不后悔！

代码如下：

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

public class Counter {

public static void main(String[] args) {

CounterFrame frame = new CounterFrame();

frame.show();
}
}

class CounterFrame extends JFrame {

public CounterFrame() {

JMenuBar menuBar = new JMenuBar();
JMenu menuFile = new JMenu();
JMenu menuFile1 = new JMenu();
JMenu menuFile2 = new JMenu();
JMenu menuFile3 = new JMenu();
JMenuItem menuFileExit = new JMenuItem();

menuFile.setText("文件");
menuFile1.setText("编辑");
menuFile2.setText("查看");
menuFile3.setText("帮助");

menuFileExit.setText("退出");

menuFileExit.addActionListener
(
new ActionListener() {
public void actionPerformed(ActionEvent e) {
CounterFrame.this.windowClosed();
}
}
);
menuFile.add(menuFileExit);
menuBar.add(menuFile);
menuBar.add(menuFile1);
menuBar.add(menuFile2);
menuBar.add(menuFile3);

setTitle("计算器");
setJMenuBar(menuBar);
setSize(new Dimension(400, 280));

this.getContentPane().add(new Allpanel());

this.addWindowListener
(
new WindowAdapter() {
public void windowClosing(WindowEvent e) {
CounterFrame.this.windowClosed();
}
}
);
}

protected void windowClosed() {

System.exit(0);
}
}

class Tool {

public static Tool instance;
private JTextField field;
private Tool() {
this.field=new JTextField(30);
this.field.setHorizontalAlignment(JTextField.RIGHT);

}

public static Tool getinstance()
{
if(instance==null)
{
instance=new Tool();
}
return instance;

}

public JTextField getfield()
{
return (this.field);
}

}

class Allpanel extends JPanel {

public Allpanel() {
this.setLayout(new BorderLayout(0,7));
Northpanel np=new Northpanel();
Centerpanel cp=new Centerpanel();
this.add(np,BorderLayout.NORTH);
this.add(cp,BorderLayout.CENTER);
}
}

class Centercenter extends JPanel {

static Vector Vec=new Vector();
static Vector vc=new Vector();
static Vector vc1=new Vector();
static Vector vc2=new Vector();
static Vector vc3=new Vector();

static String begin="yes";
static double add;
static double jq;
static double cs;
static double cq;

static double dy;
static String jg;
static String what;
static double tool=0;
static String to="yes";

/**
* Method Centercenter
*
*
*/
public Centercenter() {
// TODO: Add your code here
final JTextField text=Tool.getinstance().getfield();
this.setLayout(new GridLayout(4,5,3,3));
String arg[] ={"7","8","9","/","sqrt","4","5","6","*","%","1","2","3","-","1/x","0","+/-",".","+","="};

for(int i=0;i<20;i++)
{
final JButton b=new JButton(arg[i]);
//this.add(new JButton(arg[i]));
this.add(b);

if(i==0||i==1||i==2||i==5||i==6||i==7||i==10||i==11||i==12||i==15)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String mark=b.getText();
String ma=text.getText();

if(vc3.contains("v3"))
{
text.setText("0."+mark);
vc3.clear();
}

else if(vc.contains("a"))
{
if(vc2.contains("v2"))
{
text.setText("0."+mark);
vc.clear();
vc2.clear();

}
else
{
text.setText(mark);
vc.clear();
Vec.clear();
Vec.add(mark);
}

}
else
{
text.setText(ma.trim()+mark);
Vec.add(mark);
}

begin="no";
to="yes";

}
});
}

if(i==17)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String mar=b.getText();
String m=text.getText();
if("yes".equals(begin))
{
vc3.add("v3");
}

if(vc1.contains("v1"))
{
vc2.add("v2");
vc1.clear();
}

if(!Vec.contains(".")&&!vc.contains("a"))
{
text.setText(m.trim()+mar);
Vec.add(".");
}

}
});
}

if(i==18)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
add=Double.parseDouble(ma);
if(what==null)
{
tool=add;
what="add";
}
else
{
tool=tool+add;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="+";
}
});
}
if(i==13)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
jq=Double.parseDouble(ma);

if(what==null)
{
tool=jq;
what="jq";
}
else
{
tool=tool-jq;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="-";
}
});
}

if(i==3)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
cq=Double.parseDouble(ma);
if(what==null)
{
tool=cq;
what="cq";
}

else
{
tool=tool/cq;
text.setText(String.valueOf((tool)));
}

vc.add("a");
vc1.add("v1");
to="/";
}
});
}

if(i==4)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
cq=Double.parseDouble(ma);

text.setText(String.valueOf(Math.sqrt(cq)));
}
});
}

if(i==8)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
cs=Double.parseDouble(ma);
if(what==null)
{
tool=cs;
what="cs";
}
else
{
tool=tool*cs;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="*";
}
});
}

if(i==19)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
dy=Double.parseDouble(ma);
if(what=="add")
{
jg=String.valueOf((tool+dy));
}
if(what=="jq")
{
jg=String.valueOf((tool-dy));
}
if(what=="cs")
{
jg=String.valueOf((tool*dy));
}
if(what=="cq")
{
jg=String.valueOf((tool/dy));
}
if(what==null)
{
if(to=="+")
{
tool=add;
jg=String.valueOf(tool+dy);
}

else if(to=="-")
{
tool=jq;
jg=String.valueOf(dy-tool);
}

else if(to=="*")
{
tool=cs;
jg=String.valueOf(dy*tool);
}

else if(to=="/")
{
tool=cq;
jg=String.valueOf(dy/tool);
}

else
{
jg=String.valueOf(dy);
}
}

text.setText(jg);

Vec.clear();
Vec.add(".");
vc.add("a");
vc1.add("v1");
what=null;
tool=0;

}
});
}

}

}

}

class Centernorth extends JPanel {

public Centernorth() {

final JTextField text=Tool.getinstance().getfield();

JButton jb1=new JButton("Backspace");
JButton jb2=new JButton(" CE ");
JButton jb3=new JButton(" C ");
this.add(jb1);
this.add(jb2);
this.add(jb3);

jb1.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e)
{
String back=Tool.getinstance().getfield().getText();
text.setText(backmethod(back));
Centercenter.Vec.remove(Centercenter.Vec.size()-1);

}

});

jb3.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e)
{

text.setText("0.");
Centercenter.Vec.clear();
Centercenter.Vec.add(".");
Centercenter.vc.add("a");
Centercenter.begin="yes";
Centercenter.vc1.clear();
Centercenter.what=null;
Centercenter.tool=0;

}

});

}

public String backmethod(String str)
{
return str.substring(0,str.length()-1);
}

}

class Centerpanel extends JPanel {

public Centerpanel() {
this.setLayout(new BorderLayout(8,7));
Centernorth cn=new Centernorth();
Centercenter cc=new Centercenter();
Centerwest cw=new Centerwest();
this.add(cn,BorderLayout.NORTH);
this.add(cc,BorderLayout.CENTER);
this.add(cw,BorderLayout.WEST);
}
}

class Centerwest extends JPanel {

public Centerwest() {
this.setLayout(new GridLayout(4,1,3,3));
this.add(new JButton("MC"));
this.add(new JButton("MR"));
this.add(new JButton("MS"));
this.add(new JButton("M+"));

}

}

class Northpanel extends JPanel {

private JTextField tf;

public Northpanel() {
tf=Tool.getinstance().getfield();
this.add(tf);
}
}

---------------------------------------------------------------------------
=============《按你要求特意后改过的最简单功能的代码如下》========================

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

public class Counter2 {

public static void main(String[] args) {

CounterFrame frame = new CounterFrame();

frame.show();
}
}

class CounterFrame extends JFrame {

public CounterFrame() {

setTitle("计算器");
setSize(new Dimension(400, 280));

this.getContentPane().add(new Allpanel());

this.addWindowListener
(
new WindowAdapter() {
public void windowClosing(WindowEvent e) {
CounterFrame.this.windowClosed();
}
}
);
}

protected void windowClosed() {

System.exit(0);
}
}

class Tool {

public static Tool instance;
private JTextField field;
private Tool() {
this.field=new JTextField(30);
this.field.setHorizontalAlignment(JTextField.RIGHT);

}

public static Tool getinstance()
{
if(instance==null)
{
instance=new Tool();
}
return instance;

}

public JTextField getfield()
{
return (this.field);
}

}

class Allpanel extends JPanel {

public Allpanel() {
this.setLayout(new BorderLayout(0,7));
Northpanel np=new Northpanel();
Centerpanel cp=new Centerpanel();
this.add(np,BorderLayout.NORTH);
this.add(cp,BorderLayout.CENTER);
}
}

class Centercenter extends JPanel {

static Vector Vec=new Vector();
static Vector vc=new Vector();
static Vector vc1=new Vector();
static Vector vc2=new Vector();
static Vector vc3=new Vector();

static String begin="yes";
static double add;
static double jq;
static double cs;
static double cq;

static double dy;
static String jg;
static String what;
static double tool=0;
static String to="yes";

/**
* Method Centercenter
*
*
*/
public Centercenter() {
// TODO: Add your code here
final JTextField text=Tool.getinstance().getfield();
this.setLayout(new GridLayout(4,5,3,3));
String arg[] ={"7","8","9","/","4","5","6","*","1","2","3","-","0","=",".","+"};

for(int i=0;i<16;i++)
{
final JButton b=new JButton(arg[i]);
//this.add(new JButton(arg[i]));
this.add(b);

if(i==0||i==1||i==2||i==4||i==5||i==6||i==8||i==9||i==10||i==12)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String mark=b.getText();
String ma=text.getText();

if(vc3.contains("v3"))
{
text.setText("0."+mark);
vc3.clear();
}

else if(vc.contains("a"))
{
if(vc2.contains("v2"))
{
text.setText("0."+mark);
vc.clear();
vc2.clear();

}
else
{
text.setText(mark);
vc.clear();
Vec.clear();
Vec.add(mark);
}

}
else
{
text.setText(ma.trim()+mark);
Vec.add(mark);
}

begin="no";
to="yes";

}
});
}

if(i==14)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String mar=b.getText();
String m=text.getText();
if("yes".equals(begin))
{
vc3.add("v3");
}

if(vc1.contains("v1"))
{
vc2.add("v2");
vc1.clear();
}

if(!Vec.contains(".")&&!vc.contains("a"))
{
text.setText(m.trim()+mar);
Vec.add(".");
}

}
});
}

if(i==15)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
add=Double.parseDouble(ma);
if(what==null)
{
tool=add;
what="add";
}
else
{
tool=tool+add;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="+";
}
});
}
if(i==11)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
jq=Double.parseDouble(ma);

if(what==null)
{
tool=jq;
what="jq";
}
else
{
tool=tool-jq;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="-";
}
});
}

if(i==3)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
cq=Double.parseDouble(ma);
if(what==null)
{
tool=cq;
what="cq";
}

else
{
tool=tool/cq;
text.setText(String.valueOf((tool)));
}

vc.add("a");
vc1.add("v1");
to="/";
}
});
}

if(i==7)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
cs=Double.parseDouble(ma);
if(what==null)
{
tool=cs;
what="cs";
}
else
{
tool=tool*cs;
text.setText(String.valueOf((tool)));
}
vc.add("a");
vc1.add("v1");
to="*";
}
});
}

if(i==13)
{
b.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)

{
String ma=text.getText();
dy=Double.parseDouble(ma);
if(what=="add")
{
jg=String.valueOf((tool+dy));
}
if(what=="jq")
{
jg=String.valueOf((tool-dy));
}
if(what=="cs")
{
jg=String.valueOf((tool*dy));
}
if(what=="cq")
{
jg=String.valueOf((tool/dy));
}
if(what==null)
{
if(to=="+")
{
tool=add;
jg=String.valueOf(tool+dy);
}

else if(to=="-")
{
tool=jq;
jg=String.valueOf(dy-tool);
}

else if(to=="*")
{
tool=cs;
jg=String.valueOf(dy*tool);
}

else if(to=="/")
{
tool=cq;
jg=String.valueOf(dy/tool);
}

else
{
jg=String.valueOf(dy);
}
}

text.setText(jg);

Vec.clear();
Vec.add(".");
vc.add("a");
vc1.add("v1");
what=null;
tool=0;

}
});
}

}

}

}

class Centernorth extends JPanel {

public Centernorth() {

final JTextField text=Tool.getinstance().getfield();

}

}

class Centerpanel extends JPanel {

public Centerpanel() {
this.setLayout(new BorderLayout(8,7));
Centernorth cn=new Centernorth();
Centercenter cc=new Centercenter();
Centerwest cw=new Centerwest();
this.add(cn,BorderLayout.NORTH);
this.add(cc,BorderLayout.CENTER);
this.add(cw,BorderLayout.WEST);
}
}

class Centerwest extends JPanel {

public Centerwest() {

}

}

class Northpanel extends JPanel {

private JTextField tf;

public Northpanel() {
tf=Tool.getinstance().getfield();
this.add(tf);
}
}

------------------------------------------------------------

才子_辉祝您愉快！

给你 直接拿去运行吧
package test;

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.Menu;
import java.awt.MenuBar;
import java.awt.MenuItem;
import java.awt.Panel;
import java.awt.ScrollPane;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;

import javax.swing.JFrame;
import javax.swing.JOptionPane;

public class Calculator2 implements ActionListener {
Frame frame;
TextField textAnswer;
Panel panel, panel1, panel2, panel3;
MenuBar mainMenu;
TextField textMemory;
Label labelMemSpace;
Button buttonBk, buttonCe, buttonC;
Button button[];
Button buttonMC, buttonMR, buttonMS, buttonMAdd;
Button buttonDot, buttonAddAndSub, buttonAdd, buttonSub, buttonMul,
buttonDiv, buttonMod;
Button buttonSqrt, buttonDao, buttonEqual;
Menu editMenu, viewMenu, helpMenu;
MenuItem copyItem, pasteItem, tItem, sItem, numberGroup, topHelp, aboutCal;
DecimalFormat df;
boolean clickable;
double memoryd;
int memoryi;
double vard, answerd;
short key = -1, prekey = -1;
String copy;
TextArea help;
ScrollPane scrollHelp;

// 构造函数
public Calculator2() {
clickable = true;
answerd = 0;
frame = new JFrame("计算器");
df = new DecimalFormat("0.##############");
textAnswer = new TextField(15);
textAnswer.setText("");
textAnswer.setEditable(false);
textAnswer.setBackground(new Color(255, 255, 255));
panel = new Panel();
frame.add(panel);
panel1 = new Panel();
panel2 = new Panel();
panel.setLayout(new BorderLayout());
// 设计整个面板
mainMenu = new MenuBar();
editMenu = new Menu("编辑(E)");
viewMenu = new Menu("查看(V)");
helpMenu = new Menu("帮助(H)");
copyItem = new MenuItem(" 复制(C) Ctrl+C");
copyItem.addActionListener(this);
pasteItem = new MenuItem(" 粘贴(V) Ctrl+V");
pasteItem.addActionListener(this);
editMenu.add(copyItem);
editMenu.add(pasteItem);
tItem = new MenuItem("●标准型(T)");
tItem.addActionListener(this);
sItem = new MenuItem(" 科学型(S)");
sItem.addActionListener(this);
numberGroup = new MenuItem(" 数字分组(I)");
numberGroup.addActionListener(this);
viewMenu.add(tItem);
viewMenu.add(sItem);
viewMenu.add(numberGroup);
topHelp = new MenuItem(" 帮助主题(H)");
topHelp.addActionListener(this);
help = new TextArea(5, 20);
scrollHelp = new ScrollPane();
help.setEditable(false);
help.append("执行简单计算\n");
help.append("1. 键入计算的第一个数字。\n");
help.append("2. 单击“+”执行加、“-”执行减、“*”执行乘或“/”执行除。\n");
help.append("3. 键入计算的下一个数字。\n");
help.append("4. 输入所有剩余的运算符和数字。\n");
help.append("5. 单击“=”。\n");
aboutCal = new MenuItem(" 关于计算器(A)");
aboutCal.addActionListener(this);
helpMenu.add(topHelp);
helpMenu.add(aboutCal);
mainMenu.add(editMenu);
mainMenu.add(viewMenu);
mainMenu.add(helpMenu);
frame.setMenuBar(mainMenu);
panel.add(help);
panel.setVisible(true);
panel.add(textAnswer, BorderLayout.CENTER);
panel.add(panel1, BorderLayout.SOUTH);
panel1.setLayout(new BorderLayout());
textMemory = new TextField(3);
textMemory.setEditable(false);
textMemory.setBackground(new Color(217, 217, 217));
labelMemSpace = new Label(" ");
buttonBk = new Button("Backspace");
buttonBk.setForeground(new Color(255, 0, 0));
buttonCe = new Button("CE");
buttonCe.setForeground(new Color(255, 0, 0));
buttonC = new Button("C");
buttonC.setForeground(new Color(255, 0, 0));
buttonBk.addActionListener(this);
buttonCe.addActionListener(this);
buttonC.addActionListener(this);
panel1.add(panel2, BorderLayout.NORTH);
panel2.setLayout(new FlowLayout(FlowLayout.RIGHT));
panel2.add(textMemory);
panel2.add(labelMemSpace);
panel2.add(buttonBk);
panel2.add(buttonCe);
panel2.add(buttonC);
panel3 = new Panel();
panel1.add(panel3, BorderLayout.CENTER);
button = new Button[10];
for (int i = 0; i < button.length; i++) {
button[i] = new Button(Integer.toString(i));
button[i].setForeground(new Color(0, 0, 255));
}
buttonMC = new Button("MC");
buttonMC.setForeground(new Color(255, 0, 0));
buttonMR = new Button("MR");
buttonMR.setForeground(new Color(255, 0, 0));
buttonMS = new Button("MS");
buttonMS.setForeground(new Color(255, 0, 0));
buttonMAdd = new Button("M+");
buttonMAdd.setForeground(new Color(255, 0, 0));
buttonDot = new Button(".");
buttonDot.setForeground(new Color(0, 0, 255));
buttonAddAndSub = new Button("+/-");
buttonAddAndSub.setForeground(new Color(0, 0, 255));
buttonAdd = new Button("+");
buttonAdd.setForeground(new Color(255, 0, 0));
buttonSub = new Button("-");
buttonSub.setForeground(new Color(255, 0, 0));
buttonMul = new Button("*");
buttonMul.setForeground(new Color(255, 0, 0));
buttonDiv = new Button("/");
buttonDiv.setForeground(new Color(255, 0, 0));
buttonMod = new Button("%");
buttonMod.setForeground(new Color(0, 0, 255));
buttonSqrt = new Button("sqrt");
buttonSqrt.setForeground(new Color(0, 0, 255));
buttonDao = new Button("1/x");
buttonDao.setForeground(new Color(0, 0, 255));
buttonEqual = new Button("=");
buttonEqual.setForeground(new Color(255, 0, 0));
panel3.setLayout(new GridLayout(4, 6));
panel3.add(buttonMC);
buttonMC.addActionListener(this);
panel3.add(button[7]);
button[7].addActionListener(this);
panel3.add(button[8]);
button[8].addActionListener(this);
panel3.add(button[9]);
button[9].addActionListener(this);
panel3.add(buttonDiv);
buttonDiv.addActionListener(this);
panel3.add(buttonSqrt);
buttonSqrt.addActionListener(this);
panel3.add(buttonMR);
buttonMR.addActionListener(this);
panel3.add(button[4]);
button[4].addActionListener(this);
panel3.add(button[5]);
button[5].addActionListener(this);
panel3.add(button[6]);
button[6].addActionListener(this);
panel3.add(buttonMul);
buttonMul.addActionListener(this);
panel3.add(buttonMod);
buttonMod.addActionListener(this);
panel3.add(buttonMS);
buttonMS.addActionListener(this);
panel3.add(button[1]);
button[1].addActionListener(this);
panel3.add(button[2]);
button[2].addActionListener(this);
panel3.add(button[3]);
button[3].addActionListener(this);
panel3.add(buttonSub);
buttonSub.addActionListener(this);
panel3.add(buttonDao);
buttonDao.addActionListener(this);
panel3.add(buttonMAdd);
buttonMAdd.addActionListener(this);
panel3.add(button[0]);
button[0].addActionListener(this);
panel3.add(buttonAddAndSub);
buttonAddAndSub.addActionListener(this);
panel3.add(buttonDot);
buttonDot.addActionListener(this);
panel3.add(buttonAdd);
buttonAdd.addActionListener(this);
panel3.add(buttonEqual);
buttonEqual.addActionListener(this);
frame.pack();
frame.setVisible(true);
}

public void actionPerformed(ActionEvent event) {
boolean sign = false;
Object temp = event.getSource();
try {
for (int i = 0; i <= 9; i++)
if (temp == button[i] && clickable == true)
textAnswer.setText(textAnswer.getText()
+ Integer.toString(i));
if (temp == buttonDot && clickable == true) {
boolean isDot = false;
if (textAnswer.getText().length() == 0)
isDot = true;
for (int i = 0; i < textAnswer.getText().length(); i++)
if ('.' == textAnswer.getText().charAt(i)) {
isDot = true;
break;
}
if (isDot == false)
textAnswer.setText(textAnswer.getText() + ".");
}
if ((temp == buttonAdd || temp == buttonSub || temp == buttonMul || temp == buttonDiv)
&& clickable == true) {

if (temp == buttonAdd) {
switch (prekey) {
case 0:
answerd += Double.parseDouble(textAnswer.getText());
break;
case 1:
answerd -= Double.parseDouble(textAnswer.getText());
break;
case 2:
answerd *= Double.parseDouble(textAnswer.getText());
break;
case 3:
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else
answerd /= Double.parseDouble(textAnswer.getText());
break;
default:
answerd = Double.parseDouble(textAnswer.getText());
}
textAnswer.setText("");
prekey = key = 0;
}
// '-'操作
if (temp == buttonSub) {
switch (prekey) {
case 0:
answerd += Double.parseDouble(textAnswer.getText());
break;
case 1:
answerd -= Double.parseDouble(textAnswer.getText());
break;
case 2:
answerd *= Double.parseDouble(textAnswer.getText());
break;
case 3:
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else
answerd /= Double.parseDouble(textAnswer.getText());
break;
default:
answerd = Double.parseDouble(textAnswer.getText());
}
textAnswer.setText("");
prekey = key = 1;
}
if (temp == buttonMul) {
switch (prekey) {
case 0:
answerd += Double.parseDouble(textAnswer.getText());
break;
case 1:
answerd -= Double.parseDouble(textAnswer.getText());
break;
case 2:
answerd *= Double.parseDouble(textAnswer.getText());
break;
case 3:
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else
answerd /= Double.parseDouble(textAnswer.getText());
break;
default:
answerd = Double.parseDouble(textAnswer.getText());
}
textAnswer.setText("");
prekey = key = 2;
}
if (temp == buttonDiv) {
switch (prekey) {
case 0:
answerd += Double.parseDouble(textAnswer.getText());
break;
case 1:
answerd -= Double.parseDouble(textAnswer.getText());
break;
case 2:
answerd *= Double.parseDouble(textAnswer.getText());
break;
case 3:
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else
answerd /= Double.parseDouble(textAnswer.getText());
break;
default:
answerd = Double.parseDouble(textAnswer.getText());
}
textAnswer.setText("");
prekey = key = 3;
}
}

if (temp == buttonEqual && clickable == true) {
if (prekey == 5) {
if (key == 0) {
answerd += vard;
textAnswer.setText(df.format(answerd));
}
if (key == 1) {
answerd -= vard;
textAnswer.setText(df.format(answerd));
}
if (key == 2) {
answerd *= vard;
textAnswer.setText(df.format(answerd));
}
if (key == 3) {
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else {
answerd /= vard;
textAnswer.setText(df.format(answerd));
}
}
} else {
vard = Double.parseDouble(textAnswer.getText());
if (key == 0) {
prekey = -1;
answerd += Double.parseDouble(textAnswer.getText());
textAnswer.setText(df.format(answerd));
}
if (key == 1) {
prekey = -1;
answerd -= Double.parseDouble(textAnswer.getText());
textAnswer.setText(df.format(answerd));
}
if (key == 2) {
prekey = -1;
answerd *= Double.parseDouble(textAnswer.getText());
textAnswer.setText(df.format(answerd));
}
if (key == 3) {
prekey = -1;
if (Double.parseDouble(textAnswer.getText()) == 0) {
textAnswer.setText("除数不能为零");
clickable = false;
} else {
answerd /= Double.parseDouble(textAnswer.getText());
textAnswer.setText(df.format(answerd));
}
}
}
prekey = 5;
}
if (temp == buttonMod && clickable == true) {
if (answerd == 0) {
String s = textAnswer.getText();
textAnswer.setText(s);
} else {
boolean isDot = false;
for (int i = 0; i < textAnswer.getText().length(); i++)
if ('.' == textAnswer.getText().charAt(i)) {
isDot = true;
break;
}
if (isDot == true) {
double dtemp = Double.parseDouble(textAnswer.getText());
dtemp = dtemp / 100.0;
textAnswer.setText(Double.toString(dtemp));
} else {
if (Integer.parseInt(textAnswer.getText()) % 100 == 0) {
int itemp = Integer.parseInt(textAnswer.getText());
itemp /= 100;
textAnswer.setText(Integer.toString(itemp));
} else {
double dtemp = Double.parseDouble(textAnswer
.getText());
dtemp = dtemp / 100.0;
textAnswer.setText(Double.toString(dtemp));
}
}
}
}
if (temp == buttonSqrt && clickable == true) {
String s = textAnswer.getText();
if (s.charAt(0) == '-') {
textAnswer.setText("负数不能开根号");
clickable = false;
} else
textAnswer.setText(Double.toString(java.lang.Math
.sqrt(Double.parseDouble(textAnswer.getText()))));
}
if (temp == buttonDao && clickable == true) {
if (textAnswer.getText().charAt(0) == '0'
&& textAnswer.getText().length() == 1) {
textAnswer.setText("零不能求倒数");
clickable = false;
} else {
boolean isDec = true;
int i, j, k;
String s = Double.toString(1 / Double
.parseDouble(textAnswer.getText()));
for (i = 0; i < s.length(); i++)
if (s.charAt(i) == '.')
break;
for (j = i + 1; j < s.length(); j++)
if (s.charAt(j) != '0') {
isDec = false;
break;
}
if (isDec == true) {
String stemp = "";
for (k = 0; k < i; k++)
stemp += s.charAt(k);
textAnswer.setText(stemp);
} else
textAnswer.setText(s);
}
}
if (temp == buttonAddAndSub && clickable == true) {
boolean isNumber = true;
String s = textAnswer.getText();
for (int i = 0; i < s.length(); i++)
if (!(s.charAt(i) >= '0' && s.charAt(i) <= '9'
|| s.charAt(i) == '.' || s.charAt(i) == '-')) {
isNumber = false;
break;
}
if (isNumber == true) {
if (s.charAt(0) == '-') {
textAnswer.setText("");
for (int i = 1; i < s.length(); i++) {
char a = s.charAt(i);
textAnswer.setText(textAnswer.getText() + a);
}
} else
textAnswer.setText('-' + s);
}
}
if (temp == buttonMC && clickable == true) {
memoryd = memoryi = 0;
textMemory.setText("");
}
if (temp == buttonMS && clickable == true) {
boolean isDot = false;
textMemory.setText(" M");
for (int i = 0; i < textAnswer.getText().length(); i++)
if ('.' == textAnswer.getText().charAt(i)) {
isDot = true;
break;
}
if (isDot == true) {
memoryd = Double.parseDouble(textAnswer.getText());
memoryi = 0;
} else {
memoryi = Integer.parseInt(textAnswer.getText());
memoryd = 0;
}
}
if (temp == buttonMR && clickable == true) {
if (memoryd != 0)
textAnswer.setText(Double.toString(memoryd));
if (memoryi != 0)
textAnswer.setText(Integer.toString(memoryi));
}
if (temp == buttonMAdd && clickable == true) {
boolean isDot = false;
for (int i = 0; i < textAnswer.getText().length(); i++)
if ('.' == textAnswer.getText().charAt(i)) {
isDot = true;
break;
}
if (memoryi != 0) {
if (isDot == false)
memoryi += Integer.parseInt(textAnswer.getText());
else {
memoryd = memoryi
+ Double.parseDouble(textAnswer.getText());
memoryi = 0;
}
} else
memoryd += Double.parseDouble(textAnswer.getText());
}
if (temp == buttonBk && clickable == true) {
String s = textAnswer.getText();
textAnswer.setText("");
for (int i = 0; i < s.length() - 1; i++) {
char a = s.charAt(i);
textAnswer.setText(textAnswer.getText() + a);
}
}
if (temp == buttonCe) {
textAnswer.setText("");
clickable = true;
}
if (temp == buttonC) {
vard = answerd = 0;
textAnswer.setText("");
clickable = true;
}
if (temp == copyItem) {
copy = textAnswer.getText();
}
if (temp == pasteItem) {
textAnswer.setText(copy);
}
if (temp == topHelp) {
JOptionPane.showMessageDialog(panel, scrollHelp);
}
if (temp == numberGroup) {

}

if (temp == aboutCal) {
JOptionPane.showMessageDialog(panel, "计算器1.00版\n开发者：oО依ツ然ξo");
}
} catch (Exception e) {
textAnswer.setText("操作非法");
clickable = false;
}
}

public static void main(String args[]) {
new Calculator2();
}
}

首先建5个类，然后把我下面发的粘贴进去，我会有提示。别忘了改类名。

第一：
import java.awt.*;

import javax.swing.*;

public class F {
JFrame frame = new JFrame("计算机");

JPanel pl = new JPanel();

JPanel p2 = new JPanel();

static JTextField show = new JTextField();

static JButton b0 = new JButton("0");

static JButton b1 = new JButton("1");

static JButton b2 = new JButton("2");

static JButton b3 = new JButton("3");

static JButton b4 = new JButton("4");

static JButton b5 = new JButton("5");

static JButton b6 = new JButton("6");

static JButton b7 = new JButton("7");

static JButton b8 = new JButton("8");

static JButton b9 = new JButton("9");

JButton bjia = new JButton("+");

JButton bjian = new JButton("-");

JButton bcheng = new JButton("*");

JButton bchu = new JButton("/");

JButton bdian = new JButton(".");

JButton bdeng = new JButton("=");

JButton bqingchu = new JButton("清除");

public void y() {
pl.setLayout(new GridLayout(1, 1));
pl.add(show);
}

public void p() {
b1.addActionListener(new U());
b2.addActionListener(new U());
b3.addActionListener(new U());
b4.addActionListener(new U());
b5.addActionListener(new U());
b6.addActionListener(new U());
b7.addActionListener(new U());
b8.addActionListener(new U());
b9.addActionListener(new U());
b0.addActionListener(new U());

bjia.addActionListener(new Fu());
bjian.addActionListener(new Fu());
bcheng.addActionListener(new Fu());
bchu.addActionListener(new Fu());

bdeng.addActionListener(new Deng());
bqingchu.addActionListener(new Qing());

p2.setLayout(new GridLayout(6, 3));
p2.add(b1);
p2.add(b2);
p2.add(b3);
p2.add(b4);
p2.add(b5);
p2.add(b6);
p2.add(b7);
p2.add(b8);
p2.add(b9);
p2.add(b0);
p2.add(bjia);
p2.add(bjian);
p2.add(bcheng);
p2.add(bchu);
p2.add(bdian);
p2.add(bqingchu);
p2.add(bdeng);
}

public void o() {
frame.setLayout(new BorderLayout());
frame.add(pl, BorderLayout.NORTH);
frame.add(p2, BorderLayout.CENTER);
frame.setSize(400, 300);
frame.setVisible(true);

}

public static void main(String[] args) {
F f = new F();
f.y();
f.p();
f.o();

}

}

第二：
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class U implements ActionListener {
public static String str = "";

public static String a = "";

public static String b = "";

public static String k = "";

public void actionPerformed(ActionEvent e) {
String w = e.getActionCommand();//字

if (k.equals("")) {
a += w;
F.show.setText(a);

} else {
b += w;
F.show.setText(b);
}

}

}

第三个类：
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Deng implements ActionListener {

public void actionPerformed(ActionEvent e) {
int a = Integer.parseInt(U.a);
int b = Integer.parseInt(U.b);
int c = 0;
if (U.k.equals("+")) {
c = a + b;

} else

if (U.k.equals("-")) {
c = a - b;

} else

if (U.k.equals("*")) {
c = a * b;

} else

if (U.k.equals("/")) {
c = a / b;

} else {

}

String d = String.valueOf(c);
F.show.setText(d);
U.a = d;
U.b = "";
U.k = "";
}
}

第四个类：
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Fu implements ActionListener {

public void actionPerformed(ActionEvent e) {
String a = e.getActionCommand();//字
U.k = a;

}

}

第五个类：

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Qing implements ActionListener {

public void actionPerformed(ActionEvent e) {
U.a = "";
U.b = "";
U.k = "";
F.show.setText("");

}

}

用Applet还是用Application?

我以前老师好像也布置过一个计算器是Applet的

import java.applet.Applet;
import java.awt.Button;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

//import com.sun.org.apache.xerces.internal.impl.xpath.regex.ParseException;

public class calculator extends Applet implements ActionListener {

/**
*
*/
//private static final long serialVersionUID = 3114597813287650283L;
/* (non-Javadoc)
* @see java.applet.Applet#init()
*/
public int operator = 1; //运算符判断：1－加，2－减，3－乘，4－除；
public double accumulator=0; //运算的累加器；
public double digit = 0;
public boolean bool = true;
public boolean boolca = false;
public String text="0.0";

/*窗体控件*/
public JTextField tf_AccepteData = new JTextField();
public Button bt_Digit;
public Button bt_dot = new Button(".");
public Button bt_add = new Button("+");
public Button bt_plus = new Button("-");
public Button bt_mul = new Button("*");
public Button bt_div = new Button("/");
public Button bt_equal = new Button("=");
public Button bt_clear = new Button("C");
public Button bt_inverse = new Button("1/x");
public Button bt_non = new Button("+/-");
public Button bt_sqrt = new Button("sqrt");

public double scan()
{
text = tf_AccepteData.getText();
try{
digit = Double.parseDouble(text);
}catch(Exception msg){
msg.printStackTrace();
}
return digit;
}
public void accumulate()
{
if(!tf_AccepteData.getText().equals("")){
switch(operator){
case 1:
accumulator += digit;
tf_AccepteData.setText("" + accumulator);
break;
case 2:
accumulator -= digit;
tf_AccepteData.setText("" + accumulator);
break;
case 3:
accumulator *= digit;
tf_AccepteData.setText("" + accumulator);
break;
case 4:
if(digit == 0){
tf_AccepteData.setText("除数不能为零");
operator = 1;
accumulator = 0;
bool = true;
digit = 0;
text="";
}else{
accumulator /=digit;
tf_AccepteData.setText("" + accumulator);
}
break;
default:
break;
}
operator = 1;
}
}

public void init() {
/*初始化窗体*/
setLayout(null);
setSize(225,200);
setBackground(Color.orange);
add(tf_AccepteData);
tf_AccepteData.setHorizontalAlignment(SwingConstants.RIGHT);
tf_AccepteData.setSize(200, 25);
tf_AccepteData.setLocation(10, 10);
tf_AccepteData.setEnabled(false);
tf_AccepteData.setText("0.0");
text = tf_AccepteData.getText();
for(int i= 0; i<=9; i++){
bt_Digit = new Button("" + i);
add(bt_Digit);
bt_Digit.setSize(30, 30);
if(i>=7&&i<=9)
bt_Digit.setLocation((15+40*(i-7)), 50);
if(i>=4&&i<=6)
bt_Digit.setLocation((15+40*(i-4)), 85);
if(i>=1&&i<=3)
bt_Digit.setLocation((15+40*(i-1)), 120);
if(i==0)
bt_Digit.setLocation(15, 155);
bt_Digit.addActionListener(this);
}
/*
* 小数点
*/
add(bt_dot);
bt_dot.setSize(30, 30);
bt_dot.setLocation(95, 155);
bt_dot.addActionListener(this/*new ActionListener()*/);/*{
public void actionPerformed(ActionEvent e) {
}
});*/
/*
* 加法运算
*/
add(bt_add);
bt_add.setSize(30, 30);
bt_add.setLocation(135, 155);
bt_add.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {

accumulate();
operator = 1;
bool =true;
boolca = true;
digit = 0;
}
});
/*
* 减法运算
*/
add(bt_plus);
bt_plus.setSize(30, 30);
bt_plus.setLocation(135, 120);
bt_plus.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
accumulate();
operator = 2;
bool =true;
boolca = true;
digit = 0;
}
});
/*
* 乘法运算
*/
add(bt_mul);
bt_mul.setSize(30, 30);
bt_mul.setLocation(135, 85);
bt_mul.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
accumulate();
operator = 3;
bool =true;
boolca = true;
digit = 1;
}
});
/*
* 除法运算
*/
add(bt_div);
bt_div.setSize(30, 30);
bt_div.setLocation(135, 50);
bt_div.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
accumulate();
operator = 4;
bool =true;
boolca = true;
digit = 1;
}
});
/*
* 倒数
*/
add(bt_inverse);
bt_inverse.setSize(30, 30);
bt_inverse.setLocation(175, 120);
bt_inverse.addActionListener(new ActionListener(){
double data=0;
public void actionPerformed(ActionEvent e) {
data = scan();
if(digit==0){
tf_AccepteData.setText("取倒分母不能为零!");
operator = 1;
accumulator = 0;
bool = true;
digit = 0;
text="";
}else{
tf_AccepteData.setText("" + 1.0/data);
}
if(!boolca)
operator = 1;
}
});
/*
* 数学平方根
*/
add(bt_sqrt);
bt_sqrt.setSize(30, 30);
bt_sqrt.setLocation(175, 85);
bt_sqrt.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
scan();
if(digit<0){
tf_AccepteData.setText("函数输入无效!");
operator = 1;
accumulator = 0;
bool = true;
digit = 0;
text="";
}else{
digit = Math.sqrt(digit);
tf_AccepteData.setText("" + digit);
}
if(!boolca)
operator = 1;
}
});
/*
* 取反
*/
add(bt_non);
bt_non.setSize(30, 30);
bt_non.setLocation(55, 155);
bt_non.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
try{
digit = -Double.parseDouble(tf_AccepteData.getText());
tf_AccepteData.setText("" + digit);
}catch(Exception msg){
msg.printStackTrace();
}
if(!boolca)
operator = 1;
}
});
/*
* 等于
*/
add(bt_equal);
bt_equal.setSize(30, 30);
bt_equal.setLocation(175, 155);
bt_equal.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
accumulate();
operator = 1;
bool =true;
digit = 0;
}
});
/*
* 清零运算
*/
add(bt_clear);
bt_clear.setSize(30, 30);
bt_clear.setLocation(175, 50);
bt_clear.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
operator = 1;
accumulator = 0;
bool = true;
digit = 0;
text="";
tf_AccepteData.setText("0.0");
}
});
}
public void actionPerformed(ActionEvent e){
if(bool){
tf_AccepteData.setText("");
bool = false;
}
text = tf_AccepteData.getText();
if((text+e.getActionCommand()).indexOf(".")!=(text+e.getActionCommand()).lastIndexOf(".")) return;
text += e.getActionCommand();
if(text.equals("."))
text = "0"+text;
tf_AccepteData.setText(text);
scan();
}
}

还要写一个CalculatorTest.html网页文件代码如下，写好双击运行CalculatorTest.html就可以了

<!-------------------------CalculatorTest.html ------------------------>

<HTML>
<HEAD>
<TITLE>
小应用程序——一个简单的计算器模型
</TITLE>
</HEAD>

<BODY bgcolor = blue text = yellow >
<center>
<marquee behavior=alternate width = 300 height = 40><br>实现加、减、乘、除四种基本运算</marquee>
<br><br><br>
<APPLET ALIGN = middle CODE = "calculator.class" WIDTH = 225 HEIGHT = 200></APPLET>
<br><br><br>
<input type = button value = " 退出 " onClick="javascript:window.close()">
</center>
<BR>
</BODY>
</HTML>

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class JSQ extends JFrame implements ActionListener
{
double a= 0,b=0,d;
int k=0;
char c;
boolean i=true;
boolean m=false;
boolean n=false;
private JButton num0=new JButton("0");
private JButton num1=new JButton("1");
private JButton num2=new JButton("2");
private JButton num3=new JButton("3");
private JButton num4=new JButton("4");
private JButton num5=new JButton("5");
private JButton num6=new JButton("6");
private JButton num7=new JButton("7");
private JButton num8=new JButton("8");
private JButton num9=new JButton("9");
private JButton plu=new JButton("+");
private JButton min=new JButton("-");
private JButton mul=new JButton("x");
private JButton div=new JButton("/");
private JButton equ=new JButton("=");
private JButton cle=new JButton("C");//清除按钮
private JTextField space=new JTextField(30);

public class WindowCloser extends WindowAdapter
{
public void windowClosing(WindowEvent we)
{
System.exit(0);
}
}

public JSQ()
{
super("计算器");
JPanel text=new JPanel();
text.setLayout(new FlowLayout());
text.add(space);
JPanel buttons=new JPanel();
buttons.setLayout(new GridLayout(4,4));
buttons.add(num9);
buttons.add(num8);
buttons.add(num7);
buttons.add(plu);
buttons.add(num6);
buttons.add(num5);
buttons.add(num4);
buttons.add(min);
buttons.add(num3);
buttons.add(num2);
buttons.add(num1);
buttons.add(mul);
buttons.add(num0);
buttons.add(cle);
buttons.add(equ);
buttons.add(div);
(num9).addActionListener(this);
(num8).addActionListener(this);
(num7).addActionListener(this);
(num6).addActionListener(this);
(num5).addActionListener(this);
(num4).addActionListener(this);
(num3).addActionListener(this);
(num2).addActionListener(this);
(num1).addActionListener(this);
(num0).addActionListener(this);
(plu).addActionListener(this);
(min).addActionListener(this);
(mul).addActionListener(this);
(div).addActionListener(this);
(equ).addActionListener(this);
(cle).addActionListener(this);
setLayout(new BorderLayout());
add("North",text);
add("South",buttons);
space.setText("0");

//设置大小
setSize(400,200);
//设置可见
setVisible(true);
}

public void actionPerformed(ActionEvent e)
{
if(e.getSource()==num9)
{
if(m==true||i==true||n==true)
{
space.setText("9");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'9');
}
if(e.getSource()==num8)
{
if(m==true||i==true||n==true)
{
space.setText("8");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'8');
}
if(e.getSource()==num7)
{
if(m==true||i==true||n==true)
{
space.setText("7");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'7');
}
if(e.getSource()==num6)
{
if(m==true||i==true||n==true)
{
space.setText("6");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'6');
}
if(e.getSource()==num5)
{
if(m==true||i==true||n==true)
{
space.setText("5");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'5');
}
if(e.getSource()==num4)
{
if(m==true||i==true||n==true)
{
space.setText("4");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'4');
}
if(e.getSource()==num3)
{
if(m==true||i==true||n==true)
{
space.setText("3");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'3');
}
if(e.getSource()==num2)
{
if(m==true||i==true||n==true)
{
space.setText("2");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'2');
}
if(e.getSource()==num1)
{
if(m==true||i==true||n==true)
{
space.setText("1");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'1');
}
if(e.getSource()==num0)
{
if(m==true||i==true||n==true)
{
space.setText("0");
m=false;
i=false;
n=false;
}
else space.setText(space.getText()+'0');
}
if(e.getSource()==plu)
{
if(n==false)
{
k+=1;
if(k!=2)
a+=Double.valueOf(space.getText());
else
{
k=1;
b+=Double.valueOf(space.getText());
switch(c)
{
case '+': a+=b;b=0;break;
case '-': a-=b;b=0;break;
case 'x': a*=b;b=0;break;
case '/': if(b!=0){a/=b;b=0;}
else {space.setText("Error!");k=0;}
break;
default : break;
}
}
}
c='+';
space.setText("+");
n=true;
}
if(e.getSource()==min)
{
if(n==false)
{
k+=1;
if(k!=2)
a+=Double.valueOf(space.getText());
else
{
k=1;
b+=Double.valueOf(space.getText());
switch(c)
{
case '+': a+=b;b=0;break;
case '-': a-=b;b=0;break;
case 'x': a*=b;b=0;break;
case '/': if(b!=0){a/=b;b=0;}
else {space.setText("Error!");k=0;}
break;
default : break;
}
}
}
c='-';
space.setText("-");
n=true;
}
if(e.getSource()==mul)
{
if(n==false)
{
k+=1;
if(k!=2)
a+=Double.valueOf(space.getText());
else
{
k=1;
b+=Double.valueOf(space.getText());
switch(c)
{
case '+': a+=b;b=0;break;
case '-': a-=b;b=0;break;
case 'x': a*=b;b=0;break;
case '/': if(b!=0){a/=b;b=0;}
else {space.setText("Error!");k=0;}
break;
default : break;
}
}
}
c='x';
space.setText("x");
n=true;
}
if(e.getSource()==div)
{
if(n==false)
{
k+=1;
if(k!=2)
a+=Double.valueOf(space.getText());
else
{
k=1;
b+=Double.valueOf(space.getText());
switch(c)
{
case '+': a+=b;b=0;break;
case '-': a-=b;b=0;break;
case 'x': a*=b;b=0;break;
case '/': if(b!=0){a/=b;b=0;}
else {space.setText("Error!");k=0;}
break;
default : break;
}
}
}
c='/';
space.setText("/");
n=true;
}
if(e.getSource()==equ)
{
k=0;
if(n==true)
b=0;
else
b+=Double.valueOf(space.getText());
switch(c)
{
case '+': d=a+b;space.setText(String.valueOf(d));break;
case '-': d=a-b;space.setText(String.valueOf(d));break;
case 'x': d=a*b;space.setText(String.valueOf(d));break;
case '/': if(b!=0){d=a/b;space.setText(String.valueOf(d));}
else space.setText("Error!");
break;
default : break;
}
a=0;
b=0;
m=true;
n=false;
}
if(e.getSource()==cle)
{
space.setText("0");
a=0;
b=0;
k=0;
n=false;
i=true;
}
}

public static void main(String[] args)
{
JSQ myJSQ=new JSQ();
}
}

---

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