java计算器代码

import java.awt.*;

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import java.awt.event.*;

public class lvhaiya{

int tmp,sum,sum1,sum2=1,sum3=1;

String a,b,c,d;String s="";

Frame f=new Frame("计算器");

private String[]name={

"0","1","2","3","4","5","6","7","8","9","+","-","*","/","=","空格"

};

public Button[] button=new Button[name.length];

TextField t=new TextField("",30);

Panel p=new Panel();

Panel p1=new Panel();

Color color=new Color(100,170,90);

public lvhaiya(){

p1.setLayout(new GridLayout(5,5));

for(int i=0;iname.length;i++){

button[i]=new Button(name[i]);

p1.add(button[i]);

}

p.setLayout(new FlowLayout(FlowLayout.LEFT));

p.setBackground(color);

p.add(t);

f.add(p,BorderLayout.NORTH);

f.add(p1,BorderLayout.SOUTH);

f.pack();

f.setVisible(true);

f.addWindowListener( new WindowClose());

t.setText("0.");

for(int i=0;iname.length;i++){

button[i].addActionListener(new ButtonEventl());

}

}

public static void main(String[]args){

new lvhaiya();

}

class WindowClose extends WindowAdapter{

public void windouClosing(WindowEvent e){

System.exit(0);

}

}

class ButtonEventl implements ActionListener{

public void actionPerformed(ActionEvent e)throws ArithmeticException{

String command=e.getActionCommand();

if(command.equals("+")){

sum=Integer.parseInt(t.getText())+sum;

t.setText(String.valueOf(sum));

a=t.getText();

s="";

}

else if(command.equals("-")){

sum1=Integer.parseInt(t.getText());

b=t.getText();

s="";

}

else if(command.equals("*")){

sum2=Integer.parseInt(t.getText())*sum2;

t.setText(String.valueOf(sum2));

c=t.getText();

s="";

}

else if(command.equals("/")){

sum3=Integer.parseInt(t.getText());

d=t.getText();

s="";

}

else if(command.equals("=")){

if(a!=null){

t.setText(String.valueOf(sum+tmp));

}

if(b!=null){

t.setText(String.valueOf(sum1-tmp));

}

if(c!=null){

t.setText(String.valueOf(sum2*tmp));

}

try{

if(d!=null){

t.setText(String.valueOf(sum3/tmp));

}

}

catch(ArithmeticException a){

t.setText("除数不能为零");

}

}

else if(command.equals("空格")){

sum=0;

a=null;

b=null;

c=null;

d=null;

sum1=0;

sum2=1;

sum3=1;

tmp=0;

t.setText("0");

s="";

}

else{

s=s+command;

t.setText(s);

tmp=Integer.parseInt(s);

}

}

}

}

//按钮可以自己美化一下 希望可以帮到你

求计算器的java代码！！！

哥们，给你一个，很早写的

import java.awt.BorderLayout;

import java.awt.GridLayout;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.text.DecimalFormat;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Calculator {

//计算器面板

private JFrame f = new JFrame("Calculator");

//输入面扳

private JPanel inputPanel = new JPanel();

//加减乘除面板

private JPanel operationPanel = new JPanel();

//数字面板

private JPanel buttonsPanel = new JPanel();

//输入数据文本框

private JTextField input = new JTextField(20);

//退格键

private JButton backspace = new JButton("BackSpace");

//清空

private JButton CE = new JButton("CE ");

//删除

private JButton C = new JButton("C ");

//四则运算符号键

private JButton add = new JButton("+");

private JButton sub = new JButton("-");

private JButton mul = new JButton("*");

private JButton div = new JButton("/");

//小数点

private JButton decimal = new JButton(".");

//等号

private JButton equal = new JButton("=");

//数字键

private JButton zero = new JButton("0");

private JButton one = new JButton("1");

private JButton two = new JButton("2");

private JButton three = new JButton("3");

private JButton four = new JButton("4");

private JButton five = new JButton("5");

private JButton six = new JButton("6");

private JButton seven = new JButton("7");

private JButton eight = new JButton("8");

private JButton nine = new JButton("9");

private String num1 = "";//保存第一个运算数字

private String operator = "";//保存运算符号

public static void main(String[] args) {

new Calculator();//new计算器实例

}

public Calculator(){

//添加组件，布局

inputPanel.add(input);

f.add(inputPanel, BorderLayout.NORTH);

operationPanel.add(backspace);

operationPanel.add(CE);

operationPanel.add(C);

f.add(operationPanel, BorderLayout.CENTER);

buttonsPanel.add(add);

buttonsPanel.add(sub);

buttonsPanel.add(mul);

buttonsPanel.add(div);

buttonsPanel.add(one);

buttonsPanel.add(two);

buttonsPanel.add(three);

buttonsPanel.add(zero);

buttonsPanel.add(four);

buttonsPanel.add(five);

buttonsPanel.add(six);

buttonsPanel.add(decimal);

buttonsPanel.add(seven);

buttonsPanel.add(eight);

buttonsPanel.add(nine);

buttonsPanel.add(equal);

buttonsPanel.setLayout(new GridLayout(4, 4));

f.add(buttonsPanel, BorderLayout.SOUTH);

//注册各个组件监听事件

backspace.addMouseListener(new OperationMouseListener());

CE.addMouseListener(new OperationMouseListener());

C.addMouseListener(new OperationMouseListener());

decimal.addMouseListener(new OperationMouseListener());

equal.addMouseListener(new OperationMouseListener());

//注册四则运算监听

add.addMouseListener(new CalcMouseListener());

sub.addMouseListener(new CalcMouseListener());

mul.addMouseListener(new CalcMouseListener());

div.addMouseListener(new CalcMouseListener());

//注册数字监听事件

zero.addMouseListener(new NumberMouseListener());

one.addMouseListener(new NumberMouseListener());

two.addMouseListener(new NumberMouseListener());

three.addMouseListener(new NumberMouseListener());

four.addMouseListener(new NumberMouseListener());

five.addMouseListener(new NumberMouseListener());

six.addMouseListener(new NumberMouseListener());

seven.addMouseListener(new NumberMouseListener());

eight.addMouseListener(new NumberMouseListener());

nine.addMouseListener(new NumberMouseListener());

f.setVisible(true);

f.pack();

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

private class NumberMouseListener implements MouseListener{

public void mouseClicked(MouseEvent e) {

if(input.getText().trim().equals("0")){//如果文本框已经是0，结果还是0

input.setText(((JButton)e.getSource()).getText().trim());

}else{//否则的话，把0添加到后面，譬如文本框是1，结果就为10

input.setText(input.getText().concat(((JButton)e.getSource()).getText().trim()));

}

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

private class CalcMouseListener implements MouseListener{

//如果输入的是运算符号，保存第一个结果和运算符号

public void mouseClicked(MouseEvent e) {

num1 = input.getText().trim();input.setText("");

operator = ((JButton)e.getSource()).getText().trim();

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

private class OperationMouseListener implements MouseListener{

public void mouseClicked(MouseEvent e) {

if(e.getSource() == backspace){//退格键，删除一个直到没有字符删除

String inputText = input.getText();

if(inputText.length() 0){

input.setText(inputText.substring(0, inputText.length() - 1));

}

}else if(e.getSource() == C){

input.setText("0");//C，清空所有运算数字和符号

num1 = "";

}else if(e.getSource() == CE){

input.setText("0");//CE--将文本框置为0

}else if(e.getSource() == decimal){

String text = input.getText().trim();

//如果按了小数点，如果文本框已经有小数点，不做任何操作，否则在结果后面加上小数点

if(text.indexOf(".") == -1){

input.setText(text.concat("."));

}

}else if(e.getSource() == equal){

//如果是等号

if(!operator.trim().equals("")){

if(!input.getText().trim().equals("")){

double result = 0D;

if(operator.equals("+")){//执行加法运算

result = Double.parseDouble(num1) + Double.parseDouble(input.getText().trim());

}else if(operator.equals("-")){//减法运算

result = Double.parseDouble(num1) - Double.parseDouble(input.getText().trim());

}else if(operator.equals("*")){//乘法运算

result = Double.parseDouble(num1) * Double.parseDouble(input.getText().trim());

}else if(operator.equals("/")){//除法运算

result = Double.parseDouble(num1) / Double.parseDouble(input.getText().trim());

}

//格式化最终结果，保留两位小数点

input.setText(new DecimalFormat("0.00").format(result));

}

}

}

}

public void mouseEntered(MouseEvent e) {}

public void mouseExited(MouseEvent e) {}

public void mousePressed(MouseEvent e) {}

public void mouseReleased(MouseEvent e) {}

}

}

求java计算器的代码

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import javax.swing.*;

public class Calculator extends JFrame{

private float op1,op2;//定义两个变量存放需要运算的值

private String str="";//定义str去和text进行交叉赋值

private String opr,co;//opr存放符合，co用来存放复制的内容

private double re;//用来存放运算的结果

private boolean bo=false;//是否进行了+-*/运算

private boolean btime=false;//时间开关

Container contentpane=this.getContentPane();

JPanel panel1=new JPanel(new BorderLayout()),

panel2=new JPanel(new FlowLayout()),

panel3=new JPanel(new GridLayout(4,5)),

panel4=new JPanel(new BorderLayout()),

panel5=new JPanel(new BorderLayout());

//菜单栏

JMenuBar menubar=new JMenuBar();

JMenu edit=new JMenu("编辑(E)"),

find=new JMenu("查看(V)"),

help=new JMenu("帮助(H)");

JMenuItem copy=new JMenuItem("复制(C)",'C'),

paste=new JMenuItem("粘贴(P)",'P'),

standard=new JMenuItem("标准型(T)",'T'),

science=new JMenuItem("科学型(S)",'S'),

numarray=new JMenuItem("数字分组(I)",'I'),

helptopic=new JMenuItem("帮助主题(H)",'H'),

aboutcal=new JMenuItem("关于计算器(A)",'A');

//输入文本框

JTextField text=new JTextField(25);

//数字键

JButton one=new JButton("1"),

two=new JButton("2"),

three=new JButton("3"),

four=new JButton("4"),

five=new JButton("5"),

six=new JButton("6"),

seven=new JButton("7"),

eight=new JButton("8"),

nine=new JButton("9"),

zero=new JButton("0");

//功能键

JButton division=new JButton("/"),

multiply=new JButton("*"),

addition=new JButton("+"),

subtration=new JButton("-"),

sqrt=new JButton("sqrt"),

residual=new JButton("%"),

sign=new JButton("+/-"),

dot=new JButton("."),

reciprocal=new JButton("1/X"),

amount=new JButton("="),

backspace=new JButton("Backspace"),

ce=new JButton("CE"),

c=new JButton("C"),

time=new JButton("time");

public Calculator() {

contentpane.setLayout(new BorderLayout());

//textField文本从右边开始写

text.setHorizontalAlignment(SwingConstants.RIGHT);

text.setText("0.");

//菜单栏添加

edit.add(copy);

edit.add(paste);

find.add(standard);

find.add(science);

find.addSeparator();

find.add(numarray);

help.add(helptopic);

help.addSeparator();

help.add(aboutcal);

//把组件添加至容器中

menubar.add(edit);

menubar.add(find);

menubar.add(help);

panel1.add(menubar,"North");

panel1.add(text,"West");

//添加数字、功能键至panel2、panel3

panel2.add(backspace);

panel2.add(ce);

panel2.add(c);

panel2.add(time);

panel3.add(seven);

panel3.add(eight);

panel3.add(nine);

panel3.add(division);

panel3.add(sqrt);

panel3.add(four);

panel3.add(five);

panel3.add(six);

panel3.add(multiply);

panel3.add(residual);

panel3.add(one);

panel3.add(two);

panel3.add(three);

panel3.add(subtration);

panel3.add(reciprocal);

panel3.add(zero);

panel3.add(sign);

panel3.add(dot);

panel3.add(addition);

panel3.add(amount);

panel4.add(panel2,"North");

panel4.add(panel3,"West");

panel5.add(panel1,"North");

panel5.add(panel4,"West");

contentpane.add(panel5,"North");

//事件

//助记符

edit.setMnemonic('E');

find.setMnemonic('V');

help.setMnemonic('H');

//快捷键

KeyStroke kcopy=KeyStroke.getKeyStroke(KeyEvent.VK_C,Event.CTRL_MASK);

copy.setAccelerator(kcopy);

KeyStroke kpaste=KeyStroke.getKeyStroke(KeyEvent.VK_V,Event.CTRL_MASK);

paste.setAccelerator(kpaste);

//0-9、.的显示事件

actionlistener1 al1=new actionlistener1();

one.addActionListener(al1);

two.addActionListener(al1);

three.addActionListener(al1);

four.addActionListener(al1);

five.addActionListener(al1);

six.addActionListener(al1);

seven.addActionListener(al1);

eight.addActionListener(al1);

nine.addActionListener(al1);

//小数点的ActionListener事件

dot.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

//1.第一位就为.时改变text中内容为："0."

if(count==0){

str="0.";

text.setText(str);

}

//2.不可以重复按"."

else {if(!str.contains(".")){

str+=".";

text.setText(str);

}

else

System.out.println("您再点的话，输入的将不再是小数了！");

}

}

});

//如果第一位是0那么第二位就不可以为0

zero.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

if(bo){

if(!(str.contains("0")count==1)){

str="";

str+="0";

text.setText(str);

}else

System.out.println("您再点的话，输入的将不再是数字了！");

}

else{

if(!(str.contains("0")count==1)){

str+="0";

text.setText(str);

}else

System.out.println("您再点的话，输入的将不再是数字了！");

}

bo=false;

}

});

//+、-、*、/、%运算

actionlistener3 al3=new actionlistener3();

addition.addActionListener(al3);

subtration.addActionListener(al3);

multiply.addActionListener(al3);

division.addActionListener(al3);

residual.addActionListener(al3);

//CE和C清空按钮时间

actionlistener2 al2=new actionlistener2();

ce.addActionListener(al2);

c.addActionListener(al2);

//退格键

backspace.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length()-1;

if(bo==false){

if(count=0){

str=str.substring(0,count);

text.setText(str);

}

else

text.setText("0.");

}else

System.out.println("您现在正进行法则运算！");

}

});

//求平方根

sqrt.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

if(count!=0){

op1=Float.parseFloat(text.getText());

re=Math.sqrt(op1);

String str1=String.valueOf(re);

text.setText(str1);

str="";

}

else

System.out.println("您现在的按sqrt键毫无意义");

}

});

//求倒数

reciprocal.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

if(count!=0){

op1=Float.parseFloat(text.getText());

if(op1!=0){

re=1/op1;

String str1=String.valueOf(re);

text.setText(str1);

str=str1;

}

else{

text.setText("除数不可以为0的");

str="";

}

}

else

System.out.println("您现在的按1/X键毫无意义");

}

});

//=事件

amount.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

op2=Float.parseFloat(str);

//需判断进行那种运算法则

if(opr=="+"){//加法运算

re=op1+op2;

String str1=String.valueOf(re);

text.setText(str1);

str=String.valueOf(re);

}else{

if(opr=="-"){//减法运算

re=op1-op2;

String str1=String.valueOf(re);

text.setText(str1);

str=String.valueOf(re);

}else{

if(opr=="*"){//乘法运算

re=op1*op2;

String str1=String.valueOf(re);

text.setText(str1);

str=String.valueOf(re);

}else{

if(opr=="/"op2!=0){//除法运算

re=op1/op2;

String str1=String.valueOf(re);

text.setText(str1);

str=String.valueOf(re);

}else{

if(opr=="%"){//取余运算

re=op1%op2;

String str1=String.valueOf(re);

text.setText(str1);

str="";

}

else if(op2==0){

text.setText("除数不可以为0的");

str="";

}

}

}

}

}

//打印看看

System.out.print(op1);

System.out.print(opr);

System.out.print(op2+"=");

System.out.print(re);

System.out.println();

}

});

//复制事件

copy.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

if(count!=0){

co=text.getText();

}

else

System.out.println("没有可复制的对象");

}

});

//粘贴事件

paste.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

str=co;

text.setText(str);

}

});

//时间事件

time.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

if(btime==false){

String st=(new Date()).toString();

text.setText(st);

str="";

btime=true;

}

else{

text.setText(str);

btime=false;

}

}

});

//+/-事件

sign.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

int a=Integer.valueOf(str);

a=a*(-1);

str=String.valueOf(a);

text.setText(str);

}

});

}

//定义1-9按钮在text中显示的内部类

class actionlistener1 implements ActionListener{

public void actionPerformed(ActionEvent e){

JButton button=(JButton)e.getSource();

String btext=button.getText();

//如果第一位为0再输入其他非零的整数时将零忽略

if(bo){

if(str.indexOf("0")==0str.length()==1){

str="";

str+=btext;

text.setText(str);

}else{

str="";

str+=btext;

text.setText(str);}

}else{

if(str.indexOf("0")==0str.length()==1){

str="";

str+=btext;

text.setText(str);

}else{

str+=btext;

text.setText(str);

}

}

bo=false;

}

}

//定义清空text中内容的内部类

class actionlistener2 implements ActionListener{

public void actionPerformed(ActionEvent e){

str="";

text.setText("0.");

}

}

//定义+、-、*、/、%运算的内部类

class actionlistener3 implements ActionListener{

public void actionPerformed(ActionEvent e){

int count;

count=str.length();

if(count!=0){

JButton button=(JButton)e.getSource();

opr=button.getText();

op1=Float.parseFloat(str);

bo=true;

}

else

System.out.println("您现在的按键毫无意义！");

}

}

public static void main(String[] args){

Calculator cc=new Calculator();

cc.pack();

cc.setResizable(false);//不可最大化

cc.setVisible(true);

cc.setTitle("计算器");

cc.setDefaultCloseOperation(EXIT_ON_CLOSE);

Dimension scmsize=Toolkit.getDefaultToolkit().getScreenSize();

int w=cc.getSize().width;

int h=cc.getSize().height;

int x=(scmsize.width-w)/2;

int y=(scmsize.height-h)/2;

cc.setLocation(x, y);

}

}

JAVA简单咋做，计算器代码

简单写了下，代码如下请参照：

/**

* 计算器类

* 

* @author Administrator

*

*/

public class Calculator extends JFrame implements ActionListener {

private static final long serialVersionUID = 3868243398506940702L;

// 文本框

private JTextField result;

// 按钮数组

private JButton[] buttons;

// 按钮文本

private final String[] characters = { "7", "8", "9", "/", "4", "5", "6",

"*", "1", "2", "3", "-", "0", ".", "=", "+" };

// 是否为第一个输入的数字

private boolean isFirstDigit = true;

// 运算结果

private double resultNum = 0.0;

// 运算符

private String operator = "=";

public Calculator(String title) {

// 设置标题栏

super(title);

// 初始化各组件

init();

// 注册各组件监听器

registerListener();

// 显示窗体

setVisible(true);

}

/**

* 初始化各组件

*/

private void init() {

// 常用属性初始化

setSize(220, 200);

setResizable(false);

setLocationRelativeTo(null);

setDefaultCloseOperation(EXIT_ON_CLOSE);

/* 文本框对象初始化 */

result = new JTextField("0");

// 文本右对齐

result.setHorizontalAlignment(JTextField.RIGHT);

// 设置是否可编辑

result.setEditable(false);

/* 按钮初始化 */

buttons = new JButton[characters.length];

for (int i = 0; i  buttons.length; i++) {

buttons[i] = new JButton(characters[i]);

buttons[i].setFocusable(false); // 不允许按钮定位焦点

}

/* 将文本框与按钮添加到窗体中 */

add(result, BorderLayout.NORTH);

JPanel pnl = new JPanel(new GridLayout(4, 4, 5, 5));

for (JButton jButton : buttons) {

pnl.add(jButton);

}

add(pnl);

this.getContentPane().setFocusable(true);

}

/**

* 注册监听器

*/

private void registerListener() {

for (JButton jButton : buttons) {

jButton.addActionListener(this);

}

// 注册键盘事件

this.getContentPane().addKeyListener(new KeyAdapter() {

@Override

public void keyPressed(KeyEvent e) {

String text = String.valueOf(e.getKeyChar());

if (Character.isDigit(text.charAt(0)) || ".".equals(text)) { // 数字或小数点

handleNumber(text);

} else if ("+-*/=".indexOf(text) != -1) { // 运算符

handleOperator(text);

} else if (e.getKeyCode() == 8) { // 退格键

String tmp = result.getText().trim();

if (tmp.length() == 1) {

result.setText("0");

isFirstDigit = true;

} else {

result.setText(tmp.substring(0, tmp.length() - 1));

}

}

}

});

}

@Override

public void actionPerformed(ActionEvent e) {

JButton btn = (JButton) e.getSource();

String text = btn.getText().trim();

if (Character.isDigit(text.charAt(0)) || ".".equals(text)) { // 处理数字和小数点

handleNumber(text);

} else { // 处理运算符

handleOperator(text);

}

}

/**

* 处理数字和小数点

* 

* @param text

*/

private void handleNumber(String text) {

if (isFirstDigit) { // 第一次输入

if (".".equals(text)) {

this.result.setText("0.");

} else {

this.result.setText(text);

}

} else if ("0".equals(text)  "0".equals(this.result.getText())) {

isFirstDigit = true;

return;

} else if (".".equals(text)  this.result.getText().indexOf(".") == -1) {

this.result.setText(this.result.getText() + ".");

} else if (!".".equals(text)) {

this.result.setText(this.result.getText() + text);

}

isFirstDigit = false;

}

/**

* 处理运算符

* 

* @param text

*/

private void handleOperator(String text) {

switch (operator) { // 处理各项运算  适用于JDK1.7版本的

case "+":

resultNum += Double.parseDouble(this.result.getText());

break;

case "-":

resultNum -= Double.parseDouble(this.result.getText());

break;

case "*":

resultNum *= Double.parseDouble(this.result.getText());

break;

case "/":

resultNum /= Double.parseDouble(this.result.getText());

break;

case "=":

resultNum = Double.parseDouble(this.result.getText());

break;

}

// 将文本框的值修改为运算结果

this.result.setText(String.valueOf(resultNum));

// 将点击的运算符放入operator保存

operator = text;

// 下一个数字第一次点击

isFirstDigit = true;

}

public static void main(String[] args) {

 new Calculator("My Calculator");

 }

}

运行结果如下：

有没有完整的计算器Java代码，不要有错误的，急求

package jisuanqi;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Calculator extends JFrame implements ActionListener{     //建一个Calculator类继承JFrame实现ActionListener

public static void main (String args[]){

Calculator calculator=new Calculator();     //创建对象calculator

calculator.setVisible(true);               //窗口可见

calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //关闭图标后结束程序

}

String keys []={"7","8","9","/","4","5","6","*","1","2","3","-","0",".","=","+"};//表示计算器的键的名字

String command []={"backspace","C"};//功能键

JButton KEYS []=new JButton[keys.length];//创建键对象

JButton COMMAND[]=new JButton[command.length];//功能键对象

static JTextField resultSet=new JTextField();//建一个文本框

double resultNum;        //结果

String operator="";//运算符  ---------------------------

public Calculator() {//    构造函数

super();      

init();//初始化计算器

this.setBackground(Color.WHITE);//this代表用当前构造方法创建的对象

this.setTitle("简单计算器");    //窗口标题

this.setLocation(500, 300);   //窗口大小

this.pack(); //使组件大小合适

}

void init() {      //初始化计算器

resultSet.setHorizontalAlignment(JTextField.RIGHT);     //设置文本框内容向右对齐

resultSet.setBackground(Color.WHITE);           //设置文本框背景颜色

JPanel keysPanel=new JPanel();//创建一个面板

keysPanel.setLayout(new GridLayout(4,5,3,3)); //设置面板的布局为网格型

for (int i=0;ikeys.length;i++) {      //把数字键和符号键设为按钮

KEYS[i]=new JButton(keys[i]);

keysPanel.add(KEYS[i]);            //把按钮加到面板中

}

JPanel comPanel=new JPanel();       //创建命令键面板

comPanel.setLayout(new GridLayout(1,2,3,3));//设置面板布局为网格型 

for(int i=0;icommand.length;i++) {    //把命令键设置为按钮

COMMAND[i]=new JButton(command[i]);

comPanel.add(COMMAND[i]);          //把按钮放到面板上

}

JPanel pane=new JPanel();      //创建面板

pane.setLayout(new BorderLayout());  //面板布局为区域型

pane.add(comPanel,BorderLayout.NORTH);     //把命令面板加入到大面板上

pane.add(keysPanel,BorderLayout.CENTER); //把数字键面板加到大面板

getContentPane().setLayout(new BorderLayout());     //设置底层容器的布局为区域型

getContentPane().add(resultSet,BorderLayout.NORTH);   //把文本框放到北面

getContentPane().add(pane,BorderLayout.CENTER);    //把大面板放到中央

for(int i=0;ikeys.length;i++){

KEYS[i].addActionListener(this);//为按钮添加监听器

}

for(int i=0;icommand.length;i++){

COMMAND[i].addActionListener(this);   

}

}

//处理事件  

public void actionPerformed(ActionEvent e){  

String lable=e.getActionCommand();

if(lable.equals("backspace")){      //如果命令为backspace

backspace();

}

else if (lable.equals("C")){     //如果命令为C

Clear();

}

else if (Character.isDigit(lable.charAt(0))) {       //---------------

if(resultSet.getText().equals("0")){

resultSet.setText("");

}

resultSet.setText(resultSet.getText()+lable);

}

else if (lable.equals(".")){

point();

}

else if (lable.equals("=")){

equal();

}

else {

doOperation();

resultSet.setText("");

operator=lable;

}

}

void point() {

String s=resultSet.getText();

if(s.indexOf(".")==-1){

resultSet.setText(s+".");

}

}

void equal() {

doOperation();

resultSet.setText(""+resultNum);

operator="";

}

void doOperation() {

double m=Double.parseDouble(resultSet.getText());

if(operator.equals("")){

resultNum=m;

}

if(operator.equals("+")){

resultNum+=m;

}

if(operator.equals("-")){

resultNum-=m;

}

if(operator.equals("*")){

resultNum*=m;

}

if(operator.equals("/")){

resultNum/=m;

}

}

void Clear() {     //清零

resultSet.setText("0");

}

void backspace() {    //退格

String text =resultSet.getText();

if (text.length()0){

resultSet.setText(text.substring(0, text.length()-1));//将文本最后一个字符删除

}

else if (text.length()==0){

resultSet.setText("0");

}

}

}

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