简单计算器的设计java

① java设计一个简易计算器：类名为Calculator 具有“加，减，乘，除，和求余”的功能（使用控制台输出即可

给你个思路吧。。 还有就后期改下。。
这个用swing 弄的。。 你看下希望可以帮到你。 。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Compute extends JFrame implements ActionListener
{
JButton[] btn;
JLabel lab;
JTextField text;

String s1,s2,s;

Compute(String str)
{
super(str);

lab=new JLabel("计算结果");
text=new JTextField(13);
text.setHorizontalAlignment(JTextField.RIGHT);
text.setEditable(false);//禁止文本框输入
text.setForeground(Color.red);
btn=new JButton[8];
for(int i=0;i<4;i++)
{
btn[i]=new JButton((i+1)+"");

}
btn[4]=new JButton("+");
btn[5]=new JButton("-");
btn[6]=new JButton("=");
btn[7]=new JButton("清空");

this.setLayout(new FlowLayout());
this.add(lab);
this.add(text);
for(int i=0;i<8;i++)
{
this.add(btn[i]);
btn[i].addActionListener(this);

}
this.setBounds(200,200,230,300);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.show();
}

public void actionPerformed(ActionEvent event)
{
String str=event.getActionCommand();
if(str.equals("清空"))
{
text.setText("");
}else if(str.equals("1"))
{
text.setText(text.getText()+"1");//在文本框以追加的形式显示1
}else if(str.equals("2"))
{
text.setText(text.getText()+"2");//在文本框以追加的形式显示2
}else if(str.equals("3"))
{
text.setText(text.getText()+"3");//在文本框以追加的形式显示3
}else if(str.equals("4"))
{
text.setText(text.getText()+"4");//在文本框以追加的形式显示4
}else if(str.equals("+"))
{
s1=text.getText(); //将文本框的内容赋给s1
s="+"; //将+赋给s
text.setText(""); //将文本框清空
}else if(str.equals("-"))
{
s1=text.getText(); //将文本框的内容赋给s1
s="-"; //将-赋给s
text.setText(""); //将文本框清空
}else if(str.equals("="))
{
s2=text.getText();
double d1=Double.parseDouble(s1);
double d2=Double.parseDouble(s2);
double d=0;
if(s.equals("+"))
{
d=d1+d2;
}else if(s.equals("-"))
{
d=d1-d2;
}

text.setText(d+"");//将计算结果放到文本框中

}
}

public static void main(String[] args)
{
Compute c=new Compute("计算器");
}
}

② 用JAVA编写一个简单的计算器，要求如下

以下是上图计算器的代码:

• packageComputer;

• importjava.awt.BorderLayout;

• importjava.awt.Color;

• importjava.awt.Container;

• importjava.awt.Font;

• importjava.awt.GridLayout;

• importjava.awt.event.ActionEvent;

• importjava.awt.event.ActionListener;

• importjava.util.Stack;

• importjavax.swing.JApplet;

• importjavax.swing.JButton;

• importjavax.swing.JFrame;

• importjavax.swing.JPanel;

• importjavax.swing.JTextField;

• {

• /**

• *

• */

• =1L;

• privateJTextFieldtextField=newJTextField("请输入");

• Stringoperator="";//操作

• Stringinput="";//输入的式子

• booleanflag=true;

• //booleanflag1=true;

• //booleanflag2=true;

• publicvoidinit()//覆写Applet里边的init方法

• {

• ContainerC=getContentPane();

• JButtonb[]=newJButton[16];

• JPanelpanel=newJPanel();

• C.add(textField,BorderLayout.NORTH);

• C.add(panel,BorderLayout.CENTER);

• panel.setLayout(newGridLayout(4,4,5,5));

• Stringname[]={"7","8","9","+","4","5","6","-","1","2","3","*","0","C","=","/"};//设置按钮

• for(inti=0;i<16;i++)//添加按钮

• {

• b[i]=newJButton(name[i]);

• b[i].setBackground(newColor(192,192,192));

• b[i].setForeground(Color.BLUE);//数字键设置为蓝颜色

• if(i%4==3)

• b[i].setForeground(Color.RED);

• b[i].setFont(newFont("宋体",Font.PLAIN,16));//设置字体格式

• panel.add(b[i]);

• b[i].addActionListener(this);

• }

• b[13].setForeground(Color.RED);//非数字键，即运算键设置为红颜色

• b[13].setForeground(Color.RED);

• }

• publicvoidactionPerformed(ActionEvente)

• {

• intcnt=0;

• StringactionCommand=e.getActionCommand();

• if(actionCommand.equals("+")||actionCommand.equals("-")||actionCommand.equals("*")||actionCommand.equals("/"))

• input+=""+actionCommand+"";//设置输入，把输入的样式改成需要的样子

• elseif(actionCommand.equals("C"))

• input="";

• elseif(actionCommand.equals("="))//当监听到等号时，则处理input

• {

• input+="="+compute(input);

• textField.setText(input);

• input="";

• cnt=1;

• }

• else

• input+=actionCommand;//数字为了避免多位数的输入不需要加空格

• if(cnt==0)

• textField.setText(input);

• }

• privateStringcompute(Stringinput)//即1237的样例

• {

• Stringstr[];

• str=input.split("");

• Stack<Double>s=newStack<Double>();

• doublem=Double.parseDouble(str[0]);

• s.push(m);

• for(inti=1;i<str.length;i++)

• {

• if(i%2==1)

• {

• if(str[i].compareTo("+")==0)

• {

• doublehelp=Double.parseDouble(str[i+1]);

• s.push(help);

• }

• if(str[i].compareTo("-")==0)

• {

• doublehelp=Double.parseDouble(str[i+1]);

• s.push(-help);

• }

• if(str[i].compareTo("*")==0)

• {

• doublehelp=Double.parseDouble(str[i+1]);

• doubleans=s.peek();//取出栈顶元素

• s.pop();//消栈

• ans*=help;

• s.push(ans);

• }

• if(str[i].compareTo("/")==0)

• {

• doublehelp=Double.parseDouble(str[i+1]);

• doubleans=s.peek();

• s.pop();

• ans/=help;

• s.push(ans);

• }

• }

• }

• doubleans=0d;

• while(!s.isEmpty())

• {

• ans+=s.peek();

• s.pop();

• }

• Stringresult=String.valueOf(ans);

• returnresult;

• }

• publicstaticvoidmain(Stringargs[])

• {

• JFrameframe=newJFrame("Count");

• Countapplet=newCount();

• frame.getContentPane().add(applet,BorderLayout.CENTER);

• applet.init();//applet的init方法

• applet.start();//线程开始

• frame.setSize(350,400);//设置窗口大小

• frame.setVisible(true);//设置窗口可见

• }

• }

③ java设计一个计算器

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

public class jisuanqi extends Applet implements ActionListener
{
double x=0;
double y=0;
double w;
int h=0;
TextField t=new TextField(15);
Button b1=new Button("1");
Button b2=new Button("2");
Button b3=new Button("3");
Button b4=new Button("4");
Button b5=new Button("5");
Button b6=new Button("6");
Button b7=new Button("7");
Button b8=new Button("8");
Button b9=new Button("9");
Button b0=new Button("0");
Button b10=new Button("+");
Button b11=new Button("-");
Button b12=new Button("*");
Button b13=new Button("/");
Button b14=new Button("C");
Button b15=new Button("=");

public void init()
{
setLayout(new BorderLayout());
add(t,"North");
Panel p1=new Panel();
add(p1,"Center");
p1.setLayout(new GridLayout(4,4,5,5));
p1.add(b1);
p1.add(b2);
p1.add(b3);
p1.add(b14);
p1.add(b4);
p1.add(b5);
p1.add(b6);
p1.add(b10);
p1.add(b7);
p1.add(b8);
p1.add(b9);
p1.add(b11);
p1.add(b0);
p1.add(b12);
p1.add(b13);
p1.add(b15);
b1.addActionListener(this);
b2.addActionListener(this);
b3.addActionListener(this);
b4.addActionListener(this);
b5.addActionListener(this);
b6.addActionListener(this);
b7.addActionListener(this);
b8.addActionListener(this);
b9.addActionListener(this);
b10.addActionListener(this);
b11.addActionListener(this);
b12.addActionListener(this);
b13.addActionListener(this);
b14.addActionListener(this);
b15.addActionListener(this);
b0.addActionListener(this);
}

public void actionPerformed(ActionEvent e)
{
String ts=e.getActionCommand();
char ysf=ts.charAt(0);
if(ts=="C") t.setText("");
else if(ts=="+")
{
x=Integer.parseInt(t.getText());
t.setText("");
h=1;
}
else if(ts=="-")
{
x=Integer.parseInt(t.getText());
t.setText("");
h=2;
}
else if(ts=="*")
{
x=Integer.parseInt(t.getText());
t.setText("");
h=3;
}
else if(ts=="/")
{
x=Integer.parseInt(t.getText());
t.setText("");
h=4;
}
else if(ts.equals("="))
{
y=Integer.parseInt(t.getText());

switch(h)
{
case 1:w = x+y; break;
case 2:w = x-y; break;
case 3:w = x*y; break;
case 4:w = x/y;
}
t.setText(String.valueOf(w));
}
else
{
t.setText(t.getText()+ts);
}

}
}

④ .设计一个简单计算器,JAVA

以下是我按你的需求手写的代码，希望对你有所帮助，望采纳

importjava.awt.*;
importjava.awt.event.*;

publicclassTestextendsFrame{
	publicstaticvoidmain(Stringargs[]){
		newTest();
	}
	
	TextFieldnumber1=newTextField();
	TextFieldnumber2=newTextField();
	TextFieldresult=newTextField();
	Buttonplus=newButton("+");
	Buttonsubtract=newButton("-");
	Buttonmultiply=newButton("×");
	Buttondivide=newButton("÷");
	doublenum1,num2,resl;
	
	Test(){
		setLayout(null);
		//关闭窗口
		this.addWindowListener(newWindowAdapter(){
			publicvoidwindowClosing(WindowEvente){
				System.exit(0);
			}
		});
		setBounds(200,100,400,300);
		setTitle("简单计算器");
		//设置窗口是否可变大小
		setResizable(false);
		setVisible(true);
		number1.setBounds(100,80,150,20);
		add(number1);
		number2.setBounds(100,130,150,20);
		add(number2);
		result.setBounds(100,180,150,20);
		add(result);
		
		plus.setBounds(300,55,80,20);
		add(plus);
		plus.addActionListener(newActionListener(){
			publicvoidactionPerformed(ActionEvente){
				if(number1.getText().trim()!=""&&number2.getText().trim()!=""){
					num1=Double.parseDouble(number1.getText().trim());
					num2=Double.parseDouble(number2.getText().trim());
					resl=num1+num2;
					result.setText(String.valueOf(resl));
					number1.setText("");
					number2.setText("");
				}
			}
		});
		subtract.setBounds(300,105,80,20);
		add(subtract);
		subtract.addActionListener(newActionListener(){
			publicvoidactionPerformed(ActionEvente){
				if(number1.getText().trim()!=""&&number2.getText().trim()!=""){
					num1=Double.parseDouble(number1.getText().trim());
					num2=Double.parseDouble(number2.getText().trim());
					resl=num1-num2;
					result.setText(String.valueOf(resl));
					number1.setText("");
					number2.setText("");
				}
			}
		});
		multiply.setBounds(300,155,80,20);
		add(multiply);
		multiply.addActionListener(newActionListener(){
			publicvoidactionPerformed(ActionEvente){
				if(number1.getText().trim()!=""&&number2.getText().trim()!=""){
					num1=Double.parseDouble(number1.getText().trim());
					num2=Double.parseDouble(number2.getText().trim());
					resl=num1*num2;
					result.setText(String.valueOf(resl));
					number1.setText("");
					number2.setText("");
				}
			}
		});
		divide.setBounds(300,205,80,20);
		add(divide);
		divide.addActionListener(newActionListener(){
			publicvoidactionPerformed(ActionEvente){
				if(number1.getText().trim()!=""&&number2.getText().trim()!=""){
					num1=Double.parseDouble(number1.getText().trim());
					num2=Double.parseDouble(number2.getText().trim());
					resl=num1/num2;
					result.setText(String.valueOf(resl));
					number1.setText("");
					number2.setText("");
				}
			}
		});
	}
	
	publicvoidpaint(Graphicsg){
		g.setColor(Color.LIGHT_GRAY);
		g.fillRect(20,45,250,230);
		g.setColor(Color.BLACK);
		g.drawString("操作数",60,95);
		g.drawString("操作数",60,145);
		g.drawString("结果",70,195);
	}
}

⑤ 用java编写简单计算器

这个是我以前写的一个程序 我把里边没用的注掉了 如果你想添加其他功能 把注释解开就行了

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

public class Calculator extends JFrame {

private Container container;

private GridBagLayout layout;

private GridBagConstraints constraints;

private JTextField displayField;// 计算结果显示区

private String lastCommand;// 保存+,-,*,/,=命令

private double result;// 保存计算结果

private boolean start;// 判断是否为数字的开始

public Calculator() {

super("Calculator");
container = getContentPane();
layout = new GridBagLayout();
container.setLayout(layout);
constraints = new GridBagConstraints();
start = true;
result = 0;
lastCommand = "=";
displayField = new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx = 0;
constraints.gridy = 0;
constraints.gridwidth = 4;
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 100;
constraints.weighty = 100;
layout.setConstraints(displayField, constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
// addButton("Backspace", 0, 1, 2, 1, insert);
// addButton("CE", 2, 1, 1, 1, insert);
// addButton("C", 3, 1, 1, 1, insert);
addButton("7", 0, 2, 1, 1, insert);
addButton("8", 1, 2, 1, 1, insert);
addButton("9", 2, 2, 1, 1, insert);
addButton("/", 3, 2, 1, 1, command);
addButton("4", 0, 3, 1, 1, insert);
addButton("5", 1, 3, 1, 1, insert);
addButton("6", 2, 3, 1, 1, insert);
addButton("*", 3, 3, 1, 1, command);
addButton("1", 0, 4, 1, 1, insert);
addButton("2", 1, 4, 1, 1, insert);
addButton("3", 2, 4, 1, 1, insert);
addButton("-", 3, 4, 1, 1, command);
addButton("0", 0, 5, 1, 1, insert);
// addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
addButton(".", 2, 5, 1, 1, insert);
addButton("+", 3, 5, 1, 1, command);
addButton("=", 0, 6, 4, 1, command);
this.setResizable(false);
setSize(180, 200);
setVisible(true);

}

private void addButton(String label, int row, int column, int with,
int height, ActionListener listener) {

JButton button = new JButton(label);
constraints.gridx = row;
constraints.gridy = column;
constraints.gridwidth = with;
constraints.gridheight = height;
constraints.fill = GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button, constraints);
container.add(button);
}

private class InsertAction implements ActionListener {

public void actionPerformed(ActionEvent event) {

String input = event.getActionCommand();
if (start) {
displayField.setText("");
start = false;
if (input.equals("+/-"))
displayField.setText(displayField.getText() + "-");
}

if (!input.equals("+/-")) {
if (input.equals("Backspace")) {
String str = displayField.getText();
if (str.length() > 0)
displayField
.setText(str.substring(0, str.length() - 1));
} else if (input.equals("CE") || input.equals("C")) {
displayField.setText("0");
start = true;
} else
displayField.setText(displayField.getText() + input);
}
}
}

private class CommandAction implements ActionListener {

public void actionPerformed(ActionEvent evt) {
String command = evt.getActionCommand();
if (start) {
lastCommand = command;
} else {
calculate(Double.parseDouble(displayField.getText()));
lastCommand = command;
start = true;
}
}
}

public void calculate(double x) {
if (lastCommand.equals("+"))
result += x;
else if (lastCommand.equals("-"))
result -= x;
else if (lastCommand.equals("*"))
result *= x;
else if (lastCommand.equals("/"))
result /= x;
else if (lastCommand.equals("="))
result = x;
displayField.setText("" + result);
}

public static void main(String[] args) {
Calculator calculator = new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

}

⑥ 用Java设计一个简单的计算器。

无聊写了个，修复了下Bug：

importjava.awt.event.ActionEvent;
importjava.awt.event.ActionListener;
importjavax.swing.JButton;
importjavax.swing.JFrame;
importjavax.swing.JLabel;
importjavax.swing.JOptionPane;
importjavax.swing.JTextField;

{

=1L;

privateJButtonplus,rece,multiply,divice,reset;
privateJTextFieldone,two,result;
privatebooleandevice_falg=false;

privatefinalintwidth=400,height=300;

publicCalculate(){
super("修改密码");
this.setLayout(null);
this.setSize(width,height);
init();
Layout();
}

publicvoidinit(){
plus=newJButton("加");
rece=newJButton("减");
multiply=newJButton("乘");
divice=newJButton("除");
reset=newJButton("清空");
one=newJTextField();
two=newJTextField();
result=newJTextField();
}

publicvoidLayout(){
this.add(newJLabel("第一个数")).setBounds(20,10,60,80);
this.add(one).setBounds(100,38,100,25);
this.add(newJLabel("第二个数")).setBounds(20,40,60,80);
this.add(two).setBounds(100,70,100,25);
this.add(newJLabel("结果")).setBounds(20,85,60,80);
this.add(result).setBounds(100,110,100,25);

this.add(plus).setBounds(70,170,80,25);
this.add(rece).setBounds(200,170,80,25);
this.add(multiply).setBounds(70,200,80,25);
this.add(divice).setBounds(200,200,80,25);

this.add(reset).setBounds(300,220,80,25);

plus.addActionListener(this);
rece.addActionListener(this);
multiply.addActionListener(this);
divice.addActionListener(this);
reset.addActionListener(this);

this.setVisible(true);
this.setDefaultCloseOperation(DISPOSE_ON_CLOSE);
}

publicbooleanFormat(){
booleanFLAG=false;
booleanflag=false;
Stringone=this.one.getText().toString().trim();
Stringtwo=this.two.getText().toString().trim();

if(one==null||one.equals("")||two==null||two.equals("")){
JOptionPane.showMessageDialog(getParent(),"请输入完整信息!");
FLAG=false;
flag=true;
}

booleanboll_1=one.matches("[\d]{1,100}");
booleanboll_2=two.matches("[\d]{1,100}");
booleanboll_3=one.matches("[\d]{1,100}+[.]+[\d]{1,100}");
booleanboll_4=two.matches("[\d]{1,100}+[.]+[\d]{1,100}");
if(flag){
returnfalse;
}
if((boll_1&&boll_2)||(boll_3&&boll_4)||(boll_1&&boll_4)
||(boll_3&&boll_2)){
FLAG=true;
}else{
JOptionPane.showMessageDialog(getParent(),"请输入数字!");
FLAG=false;
}

if(FLAG&&device_falg){
if(Double.parseDouble(two)==0){
JOptionPane.showMessageDialog(getParent(),"被除数不能为0!");
FLAG=false;
device_falg=false;
}
}

returnFLAG;
}

publicdoublePlus(doubleone,doubletwo){
returnone+two;
}

publicdoubleMultiply(doubleone,doubletwo){
returnone*two;
}

publicdoubleDivice(doubleone,doubletwo){
returnone/two;
}

publicdoubleRece(doubleone,doubletwo){
returnone-two;
}

publicvoidClear(){
one.setText("");
two.setText("");
result.setText("");
}

@Override
publicvoidactionPerformed(ActionEvente){
Objecto=e.getSource();
if(o==reset){
Clear();
return;
}
if(o==divice){
device_falg=true;
}
if(!Format()){
return;
}
doubleone=Double.parseDouble(this.one.getText());
doubletwo=Double.parseDouble(this.two.getText());
doubleresult=0;
if(o==plus){
result=Plus(one,two);
}elseif(o==rece){
result=Rece(one,two);
}elseif(o==multiply){
result=Multiply(one,two);
}elseif(o==divice){
result=Divice(one,two);
}
this.result.setText(""+result);
}
publicstaticvoidmain(String[]args){
newCalculate();
}
}

⑦ java设计个简单计算器

packagezhang16;
importjava.awt.*;
importjava.awt.event.ActionEvent;
importjava.awt.event.ActionListener;
importjava.text.DecimalFormat;
importjavax.swing.*;
importjavax.swing.border.Border;
importjavax.swing.border.LineBorder;
publicclass简单计算器16_4extendsJFrame{
privatedoublenum1,num2,res;
privateJTextFieldnumber1=newJTextField(5);
privateJTextFieldnumber2=newJTextField(5);
privateJTextFieldresult=newJTextField(10);
JButtonjia=newJButton("jia");
JButtonjian=newJButton("jian");
JButtoncheng=newJButton("cheng");
JButtonchu=newJButton("chu");
public简单计算器16_4(){
//TODOAuto-generatedconstructorstub
JPanelp1=newJPanel();
JPanelp2=newJPanel();
setLayout(newGridLayout(2,1));
this.add(p1,newFlowLayout());
p1.add(newJLabel("num1"));
p1.add(number1);
p1.add(newJLabel("num"));
p1.add(number2);
p1.add(newJLabel("result"));
p1.add(result);
Borderb=newLineBorder(Color.black,1);
this.add(p2,newFlowLayout());
p2.add(jia);
p2.add(jian);
p2.add(cheng);
p2.add(chu);
p1.setBorder(b);
p2.setBorder(b);
ButtonListenerActionListener=newButtonListener();
jia.addActionListener(ActionListener);
jian.addActionListener(ActionListener);
cheng.addActionListener(ActionListener);
chu.addActionListener(ActionListener);
}
{
@Override
publicvoidactionPerformed(ActionEvente){
//TODOAuto-generatedmethodstub
DecimalFormatdf=newDecimalFormat("0.00");
if(e.getSource()==jia){
Stringnum11=number1.getText();
num1=Double.parseDouble(num11);
Stringnum22=number2.getText();
num2=Double.parseDouble(num22);
res=num1+num2;
result.setText(df.format(res)+"");
}elseif(e.getSource()==jian){
Stringnum11=number1.getText();
num1=Double.parseDouble(num11);
Stringnum22=number2.getText();
num2=Double.parseDouble(num22);
res=num1-num2;
result.setText(df.format(res)+"");
}elseif(e.getSource()==cheng){
Stringnum11=number1.getText();
num1=Double.parseDouble(num11);
Stringnum22=number2.getText();
num2=Double.parseDouble(num22);
res=num1*num2;
result.setText(df.format(res)+"");
}elseif(e.getSource()==chu){
Stringnum11=number1.getText();
num1=Double.parseDouble(num11);
Stringnum22=number2.getText();
num2=Double.parseDouble(num22);
res=num1/num2;
result.setText(df.format(res)+"");
}
}
}
publicstaticvoidmain(String[]args){
//TODOAuto-generatedmethodstub
JFramef=new简单计算器16_4();
f.setSize(400,130);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLocationRelativeTo(null);
}
}

⑧ 怎么用java编写一个简单的计算器

/*

* @(#)JCalculator.java 1.00 06/17/2015

*/

importjava.awt.*;

importjava.awt.event.*;

importjavax.swing.*;

/**

* A simple calculator program.

*<p>I saw this program in a QQ group, and help a friend correct it.</p>

*

*@authorSingyuenYip

*@version1.00 12/29/2009

*@seeJFrame

*@seeActionListener

*/

{

/**

* Serial Version UID

*/

= -169068472193786457L;

/**

* This class help close the Window.

*@authorSingyuenYip

*

*/

{

publicvoidwindowClosing(WindowEvent we) {

System.exit(0);

}

}

inti;

// Strings for Digit & Operator buttons.

privatefinalString[]str= {"7","8","9","/","4","5","6","*","1",

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

// Build buttons.

JButton[]buttons=newJButton[str.length];

// For cancel or reset.

JButtonreset=newJButton("CE");

// Build the text field to show the result.

JTextFielddisplay=newJTextField("0");

/**

* Constructor without parameters.

*/

publicJCalculator() {

super("Calculator");

// Add a panel.

JPanel panel1 =newJPanel(newGridLayout(4, 4));

// panel1.setLayout(new GridLayout(4,4));

for(i= 0;i<str.length;i++) {

buttons[i] =newJButton(str[i]);

panel1.add(buttons[i]);

}

JPanel panel2 =newJPanel(newBorderLayout());

// panel2.setLayout(new BorderLayout());

panel2.add("Center",display);

panel2.add("East",reset);

// JPanel panel3 = new Panel();

getContentPane().setLayout(newBorderLayout());

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(newWindowCloser());

// 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();

}

publicvoidactionPerformed(ActionEvent e) {

Object target = e.getSource();

String label = e.getActionCommand();

if(target ==reset)

handleReset();

elseif("0123456789.".indexOf(label) > 0)

handleNumber(label);

else

handleOperator(label);

}

// Is the first digit pressed?

booleanisFirstDigit=true;

/**

* Number handling.

*@paramkey the key of the button.

*/

publicvoidhandleNumber(String key) {

if(isFirstDigit)

display.setText(key);

elseif((key.equals(".")) && (display.getText().indexOf(".") < 0))

display.setText(display.getText() +".");

elseif(!key.equals("."))

display.setText(display.getText() + key);

isFirstDigit=false;

}

/**

* Reset the calculator.

*/

publicvoidhandleReset() {

display.setText("0");

isFirstDigit=true;

operator="=";

}

doublenumber= 0.0;

Stringoperator="=";

/**

* Handling the operation.

*@paramkey pressed operator's key.

*/

publicvoidhandleOperator(String key) {

if(operator.equals("+"))

number+= Double.valueOf(display.getText());

elseif(operator.equals("-"))

number-= Double.valueOf(display.getText());

elseif(operator.equals("*"))

number*= Double.valueOf(display.getText());

elseif(operator.equals("/"))

number/= Double.valueOf(display.getText());

elseif(operator.equals("="))

number= Double.valueOf(display.getText());

display.setText(String.valueOf(number));

operator= key;

isFirstDigit=true;

}

publicstaticvoidmain(String[] args) {

newJCalculator();

}

}

运行界面：