java计算器数字0代码的简单介绍

求计算器Java代码。。。

import java.awt.*;

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import javax.swing.*;

import java.awt.event.*;

import javax.swing.event.*;

class JPanelEa1 extends JFrame implements MenuListener,ActionListener

{

JPanel mainp,p1,p2,p3,p4;

JTextField jt1;

JMenuItem mnuCopy;

JMenuItem mnuPaste;

JButton bM;

boolean isDouble = false;// 是否为实数

int opFlag = -1;

static double t1 = 0, t2 = 0, t3 = 0, result = 0;

static int opflag1 = -1, opflag2 = -1, flag = 0, resflag = 1;

int preOp, currentOp = 0;// 标准位

double op1 = 0, op2 = 0;// 操作数

double n3;

StringBuffer buf = new StringBuffer(20);

StringBuffer copyBoard = new StringBuffer(20);// 剪贴板

StringBuffer memory = new StringBuffer(20);// M系列

StringBuffer str = new StringBuffer();

public JPanelEa1()

{

p1=new JPanel();

p1.setLayout(new GridLayout(2,1,10,10));

JMenuBar mnuNotepad=new JMenuBar();

JMenu mnuEdit=new JMenu("编辑(E)");

mnuEdit.setMnemonic(KeyEvent.VK_E);

JMenu mnuCheck=new JMenu("查看(V)");

mnuCheck.setMnemonic(KeyEvent.VK_V);

JMenu mnuHelp=new JMenu("帮助(H)");

mnuCopy=new JMenuItem("复制(C)");

mnuPaste=new JMenuItem("粘贴(P)");

JMenuItem mnuVisit=new JMenuItem("查看帮助(V)");

JMenuItem mnuAbout=new JMenuItem("关于计算器(A)");

JSeparator sep=new JSeparator();

jt1=new JTextField("0.");

jt1.setEnabled(false);

jt1.setHorizontalAlignment(JTextField.RIGHT);

mnuEdit.addMenuListener(this);

mnuCheck.addMenuListener(this);

mnuHelp.addMenuListener(this);

mnuCopy.addActionListener(this);

mnuPaste.addActionListener(this);

mnuVisit.addActionListener(this);

mnuAbout.addActionListener(this);

mnuNotepad.add(mnuEdit);

mnuNotepad.add(mnuCheck);

mnuNotepad.add(mnuHelp);

mnuEdit.add(mnuCopy);

mnuEdit.add(mnuPaste);

mnuEdit.add(sep);

mnuHelp.add(mnuVisit);

mnuHelp.add(sep);

mnuHelp.add(mnuAbout);

p1.add(mnuNotepad);

p1.add(jt1);

p2=new JPanel();

p2.setLayout(new FlowLayout(FlowLayout.CENTER));

bM = new JButton(" ");

bM.setEnabled(false);

p2.add(bM);

Button b25=new Button("Backspace");

b25.addActionListener(this);

Button b26=new Button("CE");

b26.addActionListener(this);

Button b27=new Button("C");

b27.addActionListener(this);

p2.add(b25);

p2.add(b26);

p2.add(b27);

p3=new JPanel();

p3.setLayout(new GridLayout(4,6));

Button button1=new Button("MC");

button1.addActionListener(this);

Button button2=new Button("7");

button2.addActionListener(this);

Button button3=new Button("8");

button3.addActionListener(this);

Button button4=new Button("9");

button4.addActionListener(this);

Button button5=new Button("/");

button5.addActionListener(this);

Button button6=new Button("sqrt");

button6.addActionListener(this);

Button button7=new Button("MR");

button7.addActionListener(this);

Button button8=new Button("4");

button8.addActionListener(this);

Button button9=new Button("5");

button9.addActionListener(this);

Button button10=new Button("6");

button10.addActionListener(this);

Button button11=new Button("*");

button11.addActionListener(this);

Button button12=new Button("%");

button12.addActionListener(this);

Button button13=new Button("MS");

button13.addActionListener(this);

Button button14=new Button("1");

button14.addActionListener(this);

Button button15=new Button("2");

button15.addActionListener(this);

Button button16=new Button("3");

button16.addActionListener(this);

Button button17=new Button("-");

button17.addActionListener(this);

Button button18=new Button("1/x");

button18.addActionListener(this);

Button button19=new Button("M+");

button19.addActionListener(this);

Button button20=new Button("0");

button20.addActionListener(this);

Button button21=new Button("+/-");

button21.addActionListener(this);

Button button22=new Button(".");

button22.addActionListener(this);

Button button23=new Button("+");

button23.addActionListener(this);

Button button24=new Button("=");

button24.addActionListener(this);

p3.add(button1);p3.add(button2);

p3.add(button3);p3.add(button4);

p3.add(button5);p3.add(button6);

p3.add(button7);p3.add(button8);

p3.add(button9);p3.add(button10);

p3.add(button11);p3.add(button12);

p3.add(button13);p3.add(button14);

p3.add(button15);p3.add(button16);

p3.add(button17);p3.add(button18);

p3.add(button19);p3.add(button20);

p3.add(button21);p3.add(button22);

p3.add(button23);p3.add(button24);

setSize(250,150);

mainp=new JPanel();

mainp.setLayout(new GridLayout(3,1));

mainp.add(p1);

mainp.add(p2);

mainp.add(p3);

setContentPane(mainp);

setTitle("计算器");

setSize(300,300);

setVisible(true);

setDefaultCloseOperation(EXIT_ON_CLOSE);

}

public void actionPerformed(ActionEvent e)

{

String s= e.getActionCommand();

if (s.equals("复制(C)")) {

String temp = jt1.getText().trim();

copyBoard.replace(0, copyBoard.length(), temp);

mnuPaste.setEnabled(true);

} else if (s.equals("粘贴(p)")) {

jt1.setText(copyBoard.toString());

} else if (s.equals("CE")) {

// 如果是CE则清除文本框

jt1.setText("0.");

} else if (s.equals("Backspace")) {

if (!jt1.getText().trim().equals("0.")) {

// 如果文本框中有内容

if (str.length() != 1 str.length() != 0) {

jt1.setText(str.delete(str.length() - 1, str.length())

.toString());

} else {

jt1.setText("0.");

str.setLength(0);

}

}

op2 = Double.parseDouble(jt1.getText().trim());

} else if (s.equals("C")) {

// 如果是C删除当前计算

jt1.setText("0.");

op1 = op2 = 0;

str.replace(0, str.length(), " ");

preOp = currentOp = 0;

} else if (s.equals("MC")) {

// 如果是MC则清除缓冲区

String temp = "";

memory.replace(0, memory.length(), temp);

bM.setText(" ");

} else if (s.equals("MR")) {

// 如果按键为MR则恢复缓冲区的数到文本框

jt1.setText(memory.toString());

} else if (s.equals("MS")) {

// 如果按键为MS则将文本框的数存入缓冲区

String s1 = jt1.getText().trim();

memory.replace(0, memory.length(), s1);

bM.setText("M");

} else if (s.equals("M+")) {

// 如果按键为MS则将文本框值与缓冲区的数相加但不显示结果

String temp1 = jt1.getText().trim();

double dtemp = Double.parseDouble(temp1);

String temp2 = memory.toString();

dtemp += Double.parseDouble(temp2);

temp1 = String.valueOf(dtemp);

memory.replace(0, memory.length(), temp1);

} else if (s.equals("1/x")) {

// 如果按键为1/x则将文本框中的数据为它的倒数

String temp = jt1.getText().trim();

double dtemp = Double.parseDouble(temp);

jt1.setText("" + 1 / dtemp);

} else if (s.equals("sqrt")) {

// 如果按键为sqrt则将文本框中的内容求平方根

String temp = jt1.getText().trim();

double dtemp = Double.parseDouble(temp);

jt1.setText("" + Math.sqrt(dtemp));

} else if (s.equals("+")) {

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 1;

op2 = 0;

jt1.setText("" + op1);

} else {

currentOp = preOp;

preOp = 1;

switch (currentOp) {

case 1:

op1 += op2;

jt1.setText("" + op1);

break;

case 2:

op1 -= op2;

jt1.setText("" + op1);

break;

case 3:

op1 *= op2;

jt1.setText("" + op1);

break;

case 4:

op1 /= op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("-")) {

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 2;// op1=op2;op2=0;

jt1.setText("" + op1);

} else {

currentOp = preOp;

preOp = 2;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("*"))// *

{

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 3;// op1=op2;op2=1;

jt1.setText("" + op1);// op1=op2;

} else {

currentOp = preOp;

preOp = 3;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("/"))// /

{

str.setLength(0);

if (currentOp == 0) {

preOp = currentOp = 4;// op2=1;

jt1.setText("" + op1);// op1=op2;

} else {

currentOp = preOp;

preOp = 4;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

}

} else if (s.equals("="))// =

{

if (currentOp == 0) {

str.setLength(0);

jt1.setText("" + op2);

} else {

str.setLength(0);

currentOp = preOp;

switch (currentOp) {

case 1:

op1 = op1 + op2;

jt1.setText("" + op1);

break;

case 2:

op1 = op1 - op2;

jt1.setText("" + op1);

break;

case 3:

op1 = op1 * op2;

jt1.setText("" + op1);

break;

case 4:

op1 = op1 / op2;

jt1.setText("" + op1);

break;

}

currentOp = 0;

op2 = 0;

}

} else if (s.equals(".")) {

isDouble = true;

if (jt1.getText().trim().indexOf('.') != -1)

;

else {

if (jt1.getText().trim().equals("0")) {

str.setLength(0);

jt1.setText((str.append("0" + s)).toString());

}

// else

// if(jt1.getText().trim().equals("")){}//如果初时显示为空则不做任何操作

else {

jt1.setText((str.append(s)).toString());

}

}

} else if (s.equals("0"))// 如果选择的是"0"这个数字键

{

if (jt1.getText().trim().equals("0.")) {

} else {

jt1.setText(str.append(s).toString());

op2 = Double.parseDouble(jt1.getText().trim());

}

} else {

jt1.setText(str.append(s).toString());

op2 = Double.parseDouble(jt1.getText().trim());

if (currentOp == 0)

op1 = op2;

}

}

public static void main(String args[])

{

JPanelEa1 g=new JPanelEa1();

}

@Override

public void menuSelected(MenuEvent e) {

// TODO Auto-generated method stub

}

@Override

public void menuDeselected(MenuEvent e) {

// TODO Auto-generated method stub

}

@Override

public void menuCanceled(MenuEvent e) {

// TODO Auto-generated method stub

}

}

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计算器，如果初始状态是0那么再输入其他数字时，把0覆盖掉。例如0，输入6，显示"6"，而不是"06"

Num = textField.getText() + Num;

这里如果 textField.getText() 获取到的是 0

Num 为输入的 1

textField.getText() + Num 这里不会进行运行 0+1=1

而是 "0"+"1"="01" 字符串拼接

java计算器的源代码

import java.awt.*;

import java.awt.event.*;

import java.lang.*;

import javax.swing.*;

public class Counter extends Frame

{

//声明三个面板的布局

GridLayout gl1,gl2,gl3;

Panel p0,p1,p2,p3;

JTextField tf1;

TextField tf2;

Button b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,b10,b11,b12,b13,b14,b15,b16,b17,b18,b19,b20,b21,b22,b23,b24,b25,b26;

StringBuffer str;//显示屏所显示的字符串

double x,y;//x和y都是运算数

int z;//Z表示单击了那一个运算符.0表示"+",1表示"-",2表示"*",3表示"/"

static double m;//记忆的数字

public Counter()

{

gl1=new GridLayout(1,4,10,0);//实例化三个面板的布局

gl2=new GridLayout(4,1,0,15);

gl3=new GridLayout(4,5,10,15);

tf1=new JTextField(27);//显示屏

tf1.setHorizontalAlignment(JTextField.RIGHT);

tf1.setEnabled(false);

tf1.setText("0");

tf2=new TextField(10);//显示记忆的索引值

tf2.setEditable(false);

//实例化所有按钮、设置其前景色并注册监听器

b0=new Button("Backspace");

b0.setForeground(Color.red);

b0.addActionListener(new Bt());

b1=new Button("CE");

b1.setForeground(Color.red);

b1.addActionListener(new Bt());

b2=new Button("C");

b2.setForeground(Color.red);

b2.addActionListener(new Bt());

b3=new Button("MC");

b3.setForeground(Color.red);

b3.addActionListener(new Bt());

b4=new Button("MR");

b4.setForeground(Color.red);

b4.addActionListener(new Bt());

b5=new Button("MS");

b5.setForeground(Color.red);

b5.addActionListener(new Bt());

b6=new Button("M+");

b6.setForeground(Color.red);

b6.addActionListener(new Bt());

b7=new Button("7");

b7.setForeground(Color.blue);

b7.addActionListener(new Bt());

b8=new Button("8");

b8.setForeground(Color.blue);

b8.addActionListener(new Bt());

b9=new Button("9");

b9.setForeground(Color.blue);

b9.addActionListener(new Bt());

b10=new Button("/");

b10.setForeground(Color.red);

b10.addActionListener(new Bt());

b11=new Button("sqrt");

b11.setForeground(Color.blue);

b11.addActionListener(new Bt());

b12=new Button("4");

b12.setForeground(Color.blue);

b12.addActionListener(new Bt());

b13=new Button("5");

b13.setForeground(Color.blue);

b13.addActionListener(new Bt());

b14=new Button("6");

b14.setForeground(Color.blue);

b14.addActionListener(new Bt());

b15=new Button("*");

b15.setForeground(Color.red);

b15.addActionListener(new Bt());

b16=new Button("%");

b16.setForeground(Color.blue);

b16.addActionListener(new Bt());

b17=new Button("1");

b17.setForeground(Color.blue);

b17.addActionListener(new Bt());

b18=new Button("2");

b18.setForeground(Color.blue);

b18.addActionListener(new Bt());

b19=new Button("3");

b19.setForeground(Color.blue);

b19.addActionListener(new Bt());

b20=new Button("-");

b20.setForeground(Color.red);

b20.addActionListener(new Bt());

b21=new Button("1/X");

b21.setForeground(Color.blue);

b21.addActionListener(new Bt());

b22=new Button("0");

b22.setForeground(Color.blue);

b22.addActionListener(new Bt());

b23=new Button("+/-");

b23.setForeground(Color.blue);

b23.addActionListener(new Bt());

b24=new Button(".");

b24.setForeground(Color.blue);

b24.addActionListener(new Bt());

b25=new Button("+");

b25.setForeground(Color.red);

b25.addActionListener(new Bt());

b26=new Button("=");

b26.setForeground(Color.red);

b26.addActionListener(new Bt());

//实例化四个面板

p0=new Panel();

p1=new Panel();

p2=new Panel();

p3=new Panel();

//创建一个空字符串缓冲区

str=new StringBuffer();

//添加面板p0中的组件和设置其在框架中的位置和大小

p0.add(tf1);

p0.setBounds(10,25,300,40);

//添加面板p1中的组件和设置其在框架中的位置和大小

p1.setLayout(gl1);

p1.add(tf2);

p1.add(b0);

p1.add(b1);

p1.add(b2);

p1.setBounds(10,65,300,25);

//添加面板p2中的组件并设置其的框架中的位置和大小

p2.setLayout(gl2);

p2.add(b3);

p2.add(b4);

p2.add(b5);

p2.add(b6);

p2.setBounds(10,110,40,150);

//添加面板p3中的组件并设置其在框架中的位置和大小

p3.setLayout(gl3);//设置p3的布局

p3.add(b7);

p3.add(b8);

p3.add(b9);

p3.add(b10);

p3.add(b11);

p3.add(b12);

p3.add(b13);

p3.add(b14);

p3.add(b15);

p3.add(b16);

p3.add(b17);

p3.add(b18);

p3.add(b19);

p3.add(b20);

p3.add(b21);

p3.add(b22);

p3.add(b23);

p3.add(b24);

p3.add(b25);

p3.add(b26);

p3.setBounds(60,110,250,150);

//设置框架中的布局为空布局并添加4个面板

setLayout(null);

add(p0);

add(p1);

add(p2);

add(p3);

setResizable(false);//禁止调整框架的大小

//匿名类关闭窗口

addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e1)

{

System.exit(0);

}

});

setBackground(Color.lightGray);

setBounds(100,100,320,280);

setVisible(true);

}

//构造监听器

class Bt implements ActionListener

{

public void actionPerformed(ActionEvent e2)

{

try{

if(e2.getSource()==b1)//选择"CE"清零

{

tf1.setText("0");//把显示屏清零

str.setLength(0);//清空字符串缓冲区以准备接收新的输入运算数

}

else if(e2.getSource()==b2)//选择"C"清零

{

tf1.setText("0");//把显示屏清零

str.setLength(0);

}

else if(e2.getSource()==b23)//单击"+/-"选择输入的运算数是正数还是负数

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText(""+(-x));

}

else if(e2.getSource()==b25)//单击加号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);//清空缓冲区以便接收新的另一个运算数

y=0d;

z=0;

}

else if(e2.getSource()==b20)//单击减号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=1;

}

else if(e2.getSource()==b15)//单击乘号按钮获得x的值和z的值并清空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=2;

}

else if(e2.getSource()==b10)//单击除号按钮获得x的值和z的值并空y的值

{

x=Double.parseDouble(tf1.getText().trim());

str.setLength(0);

y=0d;

z=3;

}

else if(e2.getSource()==b26)//单击等号按钮输出计算结果

{

str.setLength(0);

switch(z)

{

case 0 : tf1.setText(""+(x+y));break;

case 1 : tf1.setText(""+(x-y));break;

case 2 : tf1.setText(""+(x*y));break;

case 3 : tf1.setText(""+(x/y));break;

}

}

else if(e2.getSource()==b24)//单击"."按钮输入小数

{

if(tf1.getText().trim().indexOf(′.′)!=-1)//判断字符串中是否已经包含了小数点

{

}

else//如果没数点有小

{

if(tf1.getText().trim().equals("0"))//如果初时显示为0

{

str.setLength(0);

tf1.setText((str.append("0"+e2.getActionCommand())).toString());

}

else if(tf1.getText().trim().equals(""))//如果初时显示为空则不做任何操作

{

}

else

{

tf1.setText(str.append(e2.getActionCommand()).toString());

}

}

y=0d;

}

else if(e2.getSource()==b11)//求平方根

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText("数字格式异常");

if(x0)

tf1.setText("负数没有平方根");

else

tf1.setText(""+Math.sqrt(x));

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b16)//单击了"%"按钮

{

x=Double.parseDouble(tf1.getText().trim());

tf1.setText(""+(0.01*x));

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b21)//单击了"1/X"按钮

{

x=Double.parseDouble(tf1.getText().trim());

if(x==0)

{

tf1.setText("除数不能为零");

}

else

{

tf1.setText(""+(1/x));

}

str.setLength(0);

y=0d;

}

else if(e2.getSource()==b3)//MC为清除内存

{

m=0d;

tf2.setText("");

str.setLength(0);

}

else if(e2.getSource()==b4)//MR为重新调用存储的数据

{

if(tf2.getText().trim()!="")//有记忆数字

{

tf1.setText(""+m);

}

}

else if(e2.getSource()==b5)//MS为存储显示的数据

{

m=Double.parseDouble(tf1.getText().trim());

tf2.setText("M");

tf1.setText("0");

str.setLength(0);

}

else if(e2.getSource()==b6)//M+为将显示的数字与已经存储的数据相加要查看新的数字单击MR

{

m=m+Double.parseDouble(tf1.getText().trim());

}

else//选择的是其他的按钮

{

if(e2.getSource()==b22)//如果选择的是"0"这个数字键

{

if(tf1.getText().trim().equals("0"))//如果显示屏显示的为零不做操作

{

}

else

{

tf1.setText(str.append(e2.getActionCommand()).toString());

y=Double.parseDouble(tf1.getText().trim());

}

}

else if(e2.getSource()==b0)//选择的是“BackSpace”按钮

{

if(!tf1.getText().trim().equals("0"))//如果显示屏显示的不是零

{

if(str.length()!=1)

{

tf1.setText(str.delete(str.length()-1,str.length()).toString());//可能抛出字符串越界异常

}

else

{

tf1.setText("0");

str.setLength(0);

}

}

y=Double.parseDouble(tf1.getText().trim());

}

else//其他的数字键

{

tf1.setText(str.append(e2.getActionCommand()).toString());

y=Double.parseDouble(tf1.getText().trim());

}

}

}

catch(NumberFormatException e){

tf1.setText("数字格式异常");

}

catch(StringIndexOutOfBoundsException e){

tf1.setText("字符串索引越界");

}

}

}

public static void main(String args[])

{

new Counter();

java 计算器代码

import javax.swing.*;

import javax.swing.border.Border;

import java.awt.*;

import java.awt.event.ActionListener;

import java.awt.event.ActionEvent;

import java.math.BigDecimal;

import java.math.RoundingMode;

import java.util.HashMap;

/**

* 我的计算器。Cheshi 继承于 JFrame，是计算器的界面

c*/

public class Cheshi extends JFrame {

private Border border = BorderFactory.createEmptyBorder(5, 5, 5, 5);

private JTextField textbox = new JTextField("0");

private CalculatorCore core = new CalculatorCore();

private ActionListener listener = new ActionListener() {

public void actionPerformed(ActionEvent e) {

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

String label = b.getText();

String result = core.process(label);

textbox.setText(result);

}

};

public Cheshi(String title) throws HeadlessException {

super(title); // 调用父类构造方法

setupFrame(); // 调整窗体属性

setupControls(); // 创建控件

}

private void setupControls() {

setupDisplayPanel(); // 创建文本面板

setupButtonsPanel(); // 创建按钮面板

}

// 创建按钮面板并添加按钮

private void setupButtonsPanel() {

JPanel panel = new JPanel();

panel.setBorder(border);

panel.setLayout(new GridLayout(4, 5, 3, 3));

createButtons(panel, new String[]{

"7", "8", "9", "+", "C",

"4", "5", "6", "-", "CE",

"1", "2", "3", "*", "", // 空字符串表示这个位置没有按钮

"0", ".", "=", "/", ""

});

this.add(panel, BorderLayout.CENTER);

}

/**

* 在指定的面板上创建按钮

*

* @param panel 要创建按钮的面板

* @param labels 按钮文字

*/

private void createButtons(JPanel panel, String[] labels) {

for (String label : labels) {

// 如果 label 为空，则表示创建一个空面板。否则创建一个按钮。

if (label.equals("")) {

panel.add(new JPanel());

} else {

JButton b = new JButton(label);

b.addActionListener(listener); // 为按钮添加侦听器

panel.add(b);

}

}

}

// 设置显示面板，用一个文本框来作为计算器的显示部分。

private void setupDisplayPanel() {

JPanel panel = new JPanel();

panel.setLayout(new BorderLayout());

panel.setBorder(border);

setupTextbox();

panel.add(textbox, BorderLayout.CENTER);

this.add(panel, BorderLayout.NORTH);

}

// 调整文本框

private void setupTextbox() {

textbox.setHorizontalAlignment(JTextField.RIGHT); // 文本右对齐

textbox.setEditable(false); // 文本框只读

textbox.setBackground(Color.white); // 文本框背景色为白色

}

// 调整窗体

private void setupFrame() {

this.setDefaultCloseOperation(EXIT_ON_CLOSE); // 当窗体关闭时程序结束

this.setLocation(100, 50); // 设置窗体显示在桌面上的位置

this.setSize(300, 200); // 设置窗体大小

this.setResizable(false); // 窗体大小固定

}

// 程序入口

public static void main(String[] args) throws Exception {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

Cheshi frame = new Cheshi("我的计算器");

frame.setVisible(true); // 在桌面上显示窗体

}

}

/**

* 计算器核心逻辑。这个逻辑只能处理 1~2 个数的运算。

*/

class CalculatorCore {

private String displayText = "0"; // 要显示的文本

boolean reset = true;

private BigDecimal number1, number2;

private String operator;

private HashMapString, Operator operators = new HashMapString, Operator();

private HashMapString, Processor processors = new HashMapString, Processor();

CalculatorCore() {

setupOperators();

setupProcessors();

}

// 为每种命令添加处理方式

private void setupProcessors() {

processors.put("[0-9]", new Processor() {

public void calculate(String command) {

numberClicked(command);

}

});

processors.put("\\.", new Processor() {

public void calculate(String command) {

dotClicked();

}

});

processors.put("=", new Processor() {

public void calculate(String command) {

equalsClicked();

}

});

processors.put("[+\\-*/]", new Processor() {

public void calculate(String command) {

operatorClicked(command);

}

});

processors.put("C", new Processor() {

public void calculate(String command) {

clearClicked();

}

});

processors.put("CE", new Processor() {

public void calculate(String command) {

clearErrorClicked();

}

});

}

// 为每种 operator 添加处理方式

private void setupOperators() {

operators.put("+", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.add(number2);

}

});

operators.put("-", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.subtract(number2);

}

});

operators.put("*", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.multiply(number2);

}

});

operators.put("/", new Operator() {

public BigDecimal process(BigDecimal number1, BigDecimal number2) {

return number1.divide(number2, 30, RoundingMode.HALF_UP);

}

});

}

// 根据命令处理。这里的命令实际上就是按钮文本。

public String process(String command) {

for (String pattern : processors.keySet()) {

if (command.matches(pattern)) {

processors.get(pattern).calculate(command);

break;

}

}

return displayText;

}

// 当按下 CE 时

private void clearErrorClicked() {

if (operator == null) {

number1 = null;

} else {

number2 = null;

}

displayText = "0";

reset = true;

}

// 当按下 C 时，将计算器置为初始状态。

private void clearClicked() {

number1 = null;

number2 = null;

operator = null;

displayText = "0";

reset = true;

}

// 当按下 = 时

private void equalsClicked() {

calculateResult();

number1 = null;

number2 = null;

operator = null;

reset = true;

}

// 计算结果

private void calculateResult() {

number2 = new BigDecimal(displayText);

Operator oper = operators.get(operator);

if (oper != null) {

BigDecimal result = oper.process(number1, number2);

displayText = result.toString();

}

}

// 当按下 +-*/ 时（这里也可以扩展成其他中间操作符）

private void operatorClicked(String command) {

if (operator != null) {

calculateResult();

}

number1 = new BigDecimal(displayText);

operator = command;

reset = true;

}

// 当按下 . 时

private void dotClicked() {

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

displayText += ".";

} else if (reset) {

displayText = "0.";

}

reset = false;

}

// 当按下 0-9 时

private void numberClicked(String command) {

if (reset) {

displayText = command;

} else {

displayText += command;

}

reset = false;

}

// 运算符处理接口

interface Operator {

BigDecimal process(BigDecimal number1, BigDecimal number2);

}

// 按钮处理接口

interface Processor {

void calculate(String command);

}

}