我也刚学，不太会，刚好老师也是布置的这个任务。你看看吧。 自己改改。
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import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import java.awt.event.ActionEvent;
public class Jisuanqi extends JFrame implements ActionListener,KeyListener {
private JTextField result;
private JButton btn1,btn2,btn3,btn4,btn5,btn6,btn7,btn8,btn9,btn0,btn00,
btnAC,btnAdd,btnSub,btnResult,btnD,btnMul,btnDiv,
btnAbout,btnCancel,btnBack;
private boolean add,sub,mul,div,end,s,c=true;
private String str;
private double num1,num2;
public Jisuanqi(String title){
super(title);
JPanel p1=new JPanel();
JPanel p2=new JPanel();
JPanel p3=new JPanel();
JPanel p4=new JPanel();
JPanel p5=new JPanel();
JPanel p6=new JPanel();
//***************菜单栏****************
JMenu optMenu = new JMenu("菜单(M)");
JMenuItem inforMenu = new JMenu("作者信息(I)");
JMenuItem nameItem = new JMenuItem("伍峰杰");
JMenuItem classItem = new JMenuItem("09-1班");
JMenuItem numItem = new JMenuItem("07号");
JMenuItem exitItem = new JMenuItem("退出");
inforMenu.add(nameItem);
inforMenu.add(classItem);
inforMenu.add(numItem);
optMenu.add(inforMenu);
optMenu.add(exitItem);
exitItem.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ee)
{
System.exit(0);
}
});
JMenuBar bar = new JMenuBar();
setJMenuBar(bar);
bar.add(optMenu);
//******快捷键
optMenu.setMnemonic('m');
inforMenu.setMnemonic('i');
//****************输出文本框*************
result =new JTextField("0.0",12);
result.setFont(new Font("Serif",Font.PLAIN,25));
result.setEditable(false);
result.setHorizontalAlignment(JTextField.RIGHT);
result.setForeground(Color.BLACK);
p1.add(result);
add(p1,BorderLayout.NORTH);
//****************0-9数字按钮小数点 ************
btn0=new JButton("0");
btn0.addActionListener(this);
btn0.addKeyListener(this);
btn1=new JButton("1");
btn1.addActionListener(this);
btn1.addKeyListener(this);
btn2=new JButton("2");
btn2.addActionListener(this);
btn2.addKeyListener(this);
btn3=new JButton("3");
btn3.addActionListener(this);
btn3.addKeyListener(this);
btn4=new JButton("4");
btn4.addActionListener(this);
btn4.addKeyListener(this);
btn5=new JButton("5");
btn5.addActionListener(this);
btn5.addKeyListener(this);
btn6=new JButton("6");
btn6.addActionListener(this);
btn6.addKeyListener(this);
btn7=new JButton("7");
btn7.addActionListener(this);
btn7.addKeyListener(this);
btn8=new JButton("8");
btn8.addActionListener(this);
btn8.addKeyListener(this);
btn9=new JButton("9");
btn9.addActionListener(this);
btn9.addKeyListener(this);
btnD=new JButton(".");
btnD.addActionListener(this);
btnD.addKeyListener(this);
btnD.setForeground(Color.RED);
btn00=new JButton("00");
btn00.addActionListener(this);
p2.add(btn7);
p2.add(btn8);
p2.add(btn9);
p2.add(btn4);
p2.add(btn5);
p2.add(btn6);
p2.add(btn1);
p2.add(btn2);
p2.add(btn3);
p2.add(btn0);
p2.add(btnD);
p2.add(btn00);
p2.setLayout(new GridLayout(4,3));
add(p2,BorderLayout.CENTER);
add(p3,BorderLayout.EAST);
add(p4,BorderLayout.SOUTH);
//*******************功能键区
btnAdd=new JButton("+");
btnSub=new JButton("-");
btnMul=new JButton("×");
btnDiv=new JButton("÷");
btnAC =new JButton("Ac");
btnBack= new JButton("←");
btnResult= new JButton("=");
btnAbout= new JButton("关于");
btnAdd.addActionListener(this);
btnSub.addActionListener(this);
btnMul.addActionListener(this);
btnDiv.addActionListener(this);
btnAC.addActionListener(this);
btnBack.addActionListener(this);
btnResult.addActionListener(this);
p3.add(btnAdd);
p3.add(btnSub);
p3.add(btnMul);
p3.add(btnDiv);
p3.add(btnAC);
p3.add(btnBack);
p3.add(btnResult);
p3.add(btnAbout);
btnAdd.setToolTipText("F1");
btnSub.setToolTipText("F2");
btnMul.setToolTipText("F3");
btnDiv.setToolTipText("F4");
btnAC.setToolTipText("DELETE");
btnBack.setToolTipText("BackSpace");
btnAbout.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
JOptionPane.showMessageDialog(null,"哈理工-计算机09-1班 7号 伍峰杰","作者",JOptionPane.INFORMATION_MESSAGE);
}
}
);
p3.setLayout(new GridLayout(4,2));
}
//*******数字按钮事件
public void keyPressed(KeyEvent e)
{
if(e.getKeyCode()==KeyEvent.VK_1)
num(1);
else if (e.getKeyCode()==KeyEvent.VK_2)
num(2);
else if (e.getKeyCode()== KeyEvent.VK_3)
num(3);
else if (e.getKeyCode()== KeyEvent.VK_4)
num(4);
else if (e.getKeyCode()== KeyEvent.VK_5)
num(5);
else if (e.getKeyCode()== KeyEvent.VK_6)
num(6);
else if (e.getKeyCode()== KeyEvent.VK_7)
num(7);
else if (e.getKeyCode()== KeyEvent.VK_8)
num(8);
else if (e.getKeyCode()== KeyEvent.VK_9)
num(9);
else if (e.getKeyCode()== KeyEvent.VK_0)
num(0);
//*************小数点
else if (e.getKeyCode()== KeyEvent.VK_PERIOD){
if(c!=false){
str=result.getText();
str+=".";
result.setText(str);
btnD.setEnabled(false);
c=false;}}
//*************退格
else if (e.getKeyCode() ==KeyEvent.VK_BACK_SPACE){
str=result.getText();
if(!str.equals(""))
{str=str.substring(0,str.length()-1);
result.setText(str);
}
else btnBack.setEnabled(false);
}
//******加减乘除
else if (e.getKeyCode()== KeyEvent.VK_F1){
sign(1);
btnD.setEnabled(true);c=true;}
else if (e.getKeyCode()== KeyEvent.VK_F2){
sign(2);
btnD.setEnabled(true);c=true;}
else if (e.getKeyCode()== KeyEvent.VK_F3){
sign(3);
btnD.setEnabled(true);c=true;}
else if (e.getKeyCode()== KeyEvent.VK_F4){
sign(4);
btnD.setEnabled(true);c=true;}
//******等号
else if (e.getKeyCode()== KeyEvent.VK_ENTER){
btnD.setEnabled(true);
c=true;
num2=Double.parseDouble(result.getText());
if(add)
num1=num1+num2;
else if(sub)
num1=num1-num2;
else if(mul)
num1=num1*num2;
else if(div)
num1=num1/num2;
result.setText(String.valueOf(num1));
end=true;
}
//****** 空格全删除
else if (e.getKeyCode()== KeyEvent.VK_DELETE){
btnD.setEnabled(true);c=true;
result.setText("0.0");
num2=0;
}
}
public void keyTyped(KeyEvent e){}
public void keyReleased(KeyEvent e){}
//*************点击事件监听
public void actionPerformed(ActionEvent e){
if(e.getSource()==btn1)
num(1);
else if (e.getSource()==btn2)
num(2);
else if (e.getSource()== btn3)
num(3);
else if (e.getSource()== btn4)
num(4);
else if (e.getSource()== btn5)
num(5);
else if (e.getSource()== btn6)
num(6);
else if (e.getSource()== btn7)
num(7);
else if (e.getSource()== btn8)
num(8);
else if (e.getSource()== btn9)
num(9);
else if (e.getSource()== btn0)
num(0);
else if (e.getSource()== btn00)
num(100);
else if (e.getSource()== btnD){
str=result.getText();
str+=".";
result.setText(str);
btnD.setEnabled(false);
c=false;}
//******+-*%
else if (e.getSource()== btnAdd){
sign(1);
btnD.setEnabled(true);c=true;}
else if (e.getSource()== btnSub){
sign(2);
btnD.setEnabled(true);c=true;}
else if (e.getSource()== btnMul){
sign(3);
btnD.setEnabled(true);c=true;}
else if (e.getSource()== btnDiv){
sign(4);
btnD.setEnabled(true);c=true;}
else if (e.getSource()== btnAC){
btnD.setEnabled(true);c=true;
result.setText("0.0");
num2=0;
}
//***********=
else if (e.getSource()== btnResult){
btnD.setEnabled(true);
c=true;
num2=Double.parseDouble(result.getText());
if(add)
num1=num1+num2;
else if(sub)
num1=num1-num2;
else if(mul)
num1=num1*num2;
else if(div)
num1=num1/num2;
result.setText(String.valueOf(num1));
end=true;
//btnResult.setEnabled(false);
}
//***********Back键
else if (e.getSource() ==btnBack){
str=result.getText();
if(!str.equals(""))
{str=str.substring(0,str.length()-1);
result.setText(str);
}
else btnBack.setEnabled(false);
}
}
public void num(int i){
String s = null;
if(i!=100)
s=String.valueOf(i);
else s="00";
if(end){
result.setText("0.0");
end=false;
btnBack.setEnabled(true);
}
if((result.getText()).equals("0.0")){
result.setText(s);
btnBack.setEnabled(true);
}
else {
str=result.getText()+s;
result.setText(str);
btnBack.setEnabled(true);
}
}
public void sign(int s){
num1=Double.parseDouble(result.getText());
switch(s){
case 1:add=true;sub=false;mul=false;div=false;break;
case 2:add=false;sub=true;mul=false;div=false;break;
case 3:add=false;sub=false;mul=true;div=false;break;
case 4:
if(num1==0)result.setText("error");
else{add=false;sub=false;mul=false;div=true;break;}
}
end=true;
}
public static void main(String[] args){
Jisuanqi j=new Jisuanqi("计算器");
j.setSize(280,350);
j.setResizable(false);
j.setVisible(true);
}
}
import java.awt.Color;
import java.awt.Font;
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.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
import javax.swing.border.LineBorder;
class Normal{
double i,j;
public Normal(double num1,double num2){
i=num1;
j=num2;
}
public double puls(){
return i+j;
}
public double subtract(){
return i-j;
}
public double multiply(){
return i*j;
}
public double divide(){
return i/j;
}
public double surpuls(){
return i%j;
}
}
class scientific extends Normal{
public scientific(int num1, int num2) {
super(num1, num2);
}
}
public class calc extends JFrame{
public static void main(String[] args) {
viewNormal VN= new viewNormal("normal");
}
}
class viewNormal extends JFrame implements ActionListener{
JPanel jp1 = new JPanel(new GridLayout(4,3,5,5));
JPanel jp2 = new JPanel(new GridLayout(5,1,5,5));
JLabel jl;
JButton[] jb;
JButton jbs,jbo,jba,jbb,jbc,jby;
StringBuffer sb = new StringBuffer();
Normal normal;
int dot=0;
double fnum=0;
double lnum=0;
double result;
String sign=null;
public viewNormal(String title){
setTitle(title);
setLayout(null);
setVisible(true);
setBounds(200,200,305,350);
setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
jb= new JButton[12];
for(int i=0;i9;i++){
jb[i]=new JButton(""+(i+1));
jp1.add(jb[i]);
jb[i].addActionListener(this);
}
jb[9]=new JButton(".");
jb[10]=new JButton("0");
jb[11]=new JButton("=");
jb[9].addActionListener(this);
jb[10].addActionListener(this);
jb[11].addActionListener(this);
jp1.add(jb[9]);
jp1.add(jb[10]);
jp1.add(jb[11]);
jp1.setBounds(10, 100, 200, 200);
jbs= new JButton("+");jbo= new JButton("-");jba= new JButton("*");
jbb= new JButton("/");jby= new JButton("%");jbc= new JButton("C");
jbs.addActionListener(this);jbo.addActionListener(this);jba.addActionListener(this);
jbb.addActionListener(this);jby.addActionListener(this);jbc.addActionListener(this);
//jp2.add(jby);
jp2.add(jbs);jp2.add(jbo);jp2.add(jba);jp2.add(jbb);jp2.add(jbc);
jp2.setBounds(215, 100, 70, 200);
jl= new JLabel("0",JLabel.RIGHT);
jl.setFont(new Font("Batang",Font.BOLD, 20));
jl.setBorder(new LineBorder(Color.black,2));
jl.setBackground(Color.white);
jl.setBounds(10, 40, 275, 50);
jl.setOpaque(true);
add(jl);
add(jp1);
add(jp2);
}
//+
public void sum(){
lnum=Double.parseDouble(sb.toString());
normal=new Normal(fnum,lnum);
fnum=normal.puls();
result=fnum;
}
//-
private void sub() {
System.out.println(sb.toString());
lnum=Double.parseDouble(sb.toString());
normal=new Normal(fnum,lnum);
fnum=normal.subtract();
result=fnum;
}
//*
private void mul() {
lnum=Double.parseDouble(sb.toString());
normal=new Normal(fnum,lnum);
fnum=normal.multiply();
result=fnum;
}
// /
private void div() {
lnum=Double.parseDouble(sb.toString());
normal=new Normal(fnum,lnum);
fnum=normal.divide();
result=fnum;
}
//%
private void sur() {
lnum=Double.parseDouble(sb.toString());
normal=new Normal(fnum,lnum);
fnum=normal.surpuls();
result=fnum;
}
// =
private void same(){
if(sign.equals("+")){
sum();
}
if(sign.equals("-")){
sub();
}
if(sign.equals("*")){
mul();
}
if(sign.equals("/")){
div();
}
if(sign.equals("%")){
sur();
}
}
//result
public void Result(){
if(result%1!=0)
jl.setText(""+result);
else
{
int i=(int)result;
jl.setText(""+i);
}
}
@Override
public void actionPerformed(ActionEvent e) {
//System.out.println(sb.toString());
// 1~9
for(int i=0;i9;i++){
if(e.getSource()==jb[i]!sb.toString().equals("0")){
sb.append(jb[i].getText());
jl.setText(sb.toString());
}
else if(e.getSource()==jb[i]sb.toString().equals("0")){
int d=sb.length();
sb.delete(0, d);
sb.append(jb[i].getText());
jl.setText(sb.toString());
}
}
// 0
if(e.getSource()==jb[10]!sb.toString().equals("0")){
sb.append(jb[10].getText());
jl.setText(sb.toString());
}
// .
if(e.getSource()==jb[9]dot==0!sb.toString().equals("")){
dot++;
sb.append(jb[9].getText());
jl.setText(sb.toString());
}
// =
if(e.getSource()==jb[11]!sb.toString().equals("")){
same();
Result();
int d=sb.length();
sb.delete(0, d);
dot=0;
}
// +
if(e.getSource()==jbs!sb.toString().equals("")){
if(sign!="+"sign!=null)
same();
else
sum();
sign ="+";
Result();
int d=sb.length();
sb.delete(0, d);
dot=0;
}
//-
if(e.getSource()==jbo!sb.toString().equals("")){
if(fnum==0)
fnum=2*Double.parseDouble(sb.toString());
if(sign!="-"sign!=null)
same();
else
sub();
sign ="-";
Result();
int d=sb.length();
sb.delete(0, d);
dot=0;
}
//*
if(e.getSource()==jba!sb.toString().equals("")){
if(fnum==0)
fnum=1;
if(sign!="*"sign!=null)
same();
else
mul();
sign ="*";
Result();
int d=sb.length();
sb.delete(0, d);
dot=0;
}
// /
if(e.getSource()==jbb!sb.toString().equals("")){
if(fnum==0)
fnum=Math.pow(Double.parseDouble(sb.toString()),2);
if(sign!="/"sign!=null)
same();
else
div();
sign ="/";
Result();
int d=sb.length();
sb.delete(0, d);
dot=0;
}
//%
// if(e.getSource()==jby!sb.toString().equals("")){
// if(fnum==0){
// fnum=Double.parseDouble(sb.toString());
// result=fnum;
// }
// else {
// if(sign!="%"sign!=null)
// same();
// else{
// lnum=Double.parseDouble(sb.toString());
// normal=new Normal(fnum,lnum);
// fnum=normal.surpuls();
// result=fnum;
// }
// }
// sign ="%";
// Result();
// int d=sb.length();
// sb.delete(0, d);
// dot=0;
// }
//clear
if(e.getSource()==jbc){
int d=sb.length();
sb.delete(0, d);
jl.setText("0");
dot=0;
fnum=0;
lnum=0;
sign=null;
}
}
}
class viewScientific extends viewNormal{
public viewScientific(String title){
super(title);
setBounds(200,200,800,500);
}
}
//等号以后输入符号用不了， String转 double 本来就有错误，你可以用我的扩展成科学型的。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import java.util.LinkedList; //工具包
import java.text.NumberFormat; //文本包
/**
* java swing计算器
* @author young
*
*/
public class Calculator extends Frame implements ActionListener // 计算器类
{
JTextField result;
NumberButton numberButton[];
OperatorButton operatorButton[];
Button radixpoint, positiveminus, backspace, reciprocal, equal, clear; // 声明成员变量
// 小数点按钮,正负号按钮,退格按钮,求倒数按钮,等号按钮,清零按钮
Panel panel;
String operator[] = { "+", "-", "*", "/" };
LinkedList linklist;
boolean pressequal = false;
public Calculator() // 构造方法
{
super("计算器");
linklist = new LinkedList();
numberButton = new NumberButton[10];
for (int i = 0; i = 9; i++) {
numberButton[i] = new NumberButton(i);
numberButton[i].addActionListener(this);
}
operatorButton = new OperatorButton[4];
for (int i = 0; i 4; i++) {
operatorButton[i] = new OperatorButton(operator[i]);
operatorButton[i].addActionListener(this);
}
radixpoint = new Button(".");
positiveminus = new Button("+/-");
backspace = new Button("CE");
reciprocal = new Button("1/x");
equal = new Button("=");
clear = new Button("C");
radixpoint.setForeground(Color.red);
positiveminus.setForeground(Color.red);
backspace.setForeground(Color.red);
reciprocal.setForeground(Color.red);
equal.setForeground(Color.red);
clear.setForeground(Color.red);
radixpoint.addActionListener(this);
positiveminus.addActionListener(this);
backspace.addActionListener(this);
reciprocal.addActionListener(this);
equal.addActionListener(this);
clear.addActionListener(this);
result = new JTextField(10);
result.setHorizontalAlignment(JTextField.RIGHT);
result.setForeground(Color.black);
result.setBackground(Color.white);
result.setFont(new Font("TimesRoman", Font.PLAIN, 14));
result.setBorder(new SoftBevelBorder(BevelBorder.LOWERED));
result.setEditable(false);
panel = new Panel();
panel.setLayout(new GridLayout(4, 5));
panel.add(numberButton[1]);
panel.add(numberButton[2]);
panel.add(numberButton[3]);
panel.add(backspace);
panel.add(clear);
panel.add(numberButton[4]);
panel.add(numberButton[5]);
panel.add(numberButton[6]);
panel.add(operatorButton[0]);
panel.add(operatorButton[2]);
panel.add(numberButton[7]);
panel.add(numberButton[8]);
panel.add(numberButton[9]);
panel.add(operatorButton[1]);
panel.add(operatorButton[3]);
panel.add(numberButton[0]);
panel.add(positiveminus);
panel.add(reciprocal);
panel.add(radixpoint);
panel.add(equal);
add(result, "North");
add(panel, "Center");
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
setSize(270, 200);
setLocation(300, 230);
setVisible(true);
}
public void actionPerformed(ActionEvent e) // 按钮的单击事件处理方法
{
if (e.getSource() instanceof NumberButton) // 数字按钮
{
NumberButton b = (NumberButton) e.getSource();
if (linklist.size() == 0) {
int number = b.getNumber();
linklist.add("" + number);
result.setText("" + number);
pressequal = false;
}
else if (linklist.size() == 1 pressequal == false) {
int number = b.getNumber();
String num = (String) linklist.getFirst();
String s = num.concat("" + number);
linklist.set(0, s);
result.setText(s);
} else if (linklist.size() == 1 pressequal == true) {
int number = b.getNumber();
linklist.removeFirst();
linklist.add("" + number);
pressequal = false;
result.setText("" + number);
} else if (linklist.size() == 2) {
int number = b.getNumber();
linklist.add("" + number);
result.setText("" + number);
} else if (linklist.size() == 3) {
int number = b.getNumber();
String num = (String) linklist.getLast();
String s = num.concat("" + number);
linklist.set(2, s);
result.setText(s);
}
} else if (e.getSource() instanceof OperatorButton) // 操作按钮
{
OperatorButton b = (OperatorButton) e.getSource();
if (linklist.size() == 1) {
String fuhao = b.getOperator();
linklist.add(fuhao);
} else if (linklist.size() == 2) {
String fuhao = b.getOperator();
linklist.set(1, fuhao);
} else if (linklist.size() == 3) {
String fuhao = b.getOperator();
String number1 = (String) linklist.getFirst();
String number2 = (String) linklist.getLast();
String operator = (String) linklist.get(1);
try {
double n1 = Double.parseDouble(number1);
double n2 = Double.parseDouble(number2);
double n = 0;
if (operator.equals("+")) {
n = n1 + n2;
} else if (operator.equals("-")) {
n = n1 - n2;
} else if (operator.equals("*")) {
n = n1 * n2;
} else if (operator.equals("/")) {
n = n1 / n2;
}
linklist.clear();
linklist.add("" + n);
linklist.add(fuhao);
result.setText("" + n);
} catch (Exception ee) {
}
}
} else if (e.getSource() == equal) // 等号按钮
{
pressequal = true;
if (linklist.size() == 1 || linklist.size() == 2) {
String num = (String) linklist.getFirst();
result.setText("" + num);
} else if (linklist.size() == 3) {
String number1 = (String) linklist.getFirst();
String number2 = (String) linklist.getLast();
String operator = (String) linklist.get(1);
try {
double n1 = Double.parseDouble(number1);
double n2 = Double.parseDouble(number2);
double n = 0;
if (operator.equals("+")) {
n = n1 + n2;
} else if (operator.equals("-")) {
n = n1 - n2;
} else if (operator.equals("*")) {
n = n1 * n2;
} else if (operator.equals("/")) {
n = n1 / n2;
}
result.setText("" + n);
linklist.set(0, "" + n);
linklist.removeLast();
linklist.removeLast();
} catch (Exception ee) {
}
}
} else if (e.getSource() == radixpoint) // 小数点按钮
{
if (linklist.size() == 0) {
pressequal = false;
} else if (linklist.size() == 1) {
String dot = radixpoint.getLabel();
String num = (String) linklist.getFirst();
String s = null;
if (num.indexOf(dot) == -1) {
s = num.concat(dot);
linklist.set(0, s);
} else {
s = num;
}
linklist.set(0, s);
result.setText(s);
}
else if (linklist.size() == 3) {
String dot = radixpoint.getLabel();
String num = (String) linklist.getLast();
String s = null;
if (num.indexOf(dot) == -1) {
s = num.concat(dot);
linklist.set(2, s);
} else {
s = num;
}
result.setText(s);
}
} else if (e.getSource() == backspace) // 退格按钮
{
if (linklist.size() == 1) {
String num = (String) linklist.getFirst();
if (num.length() = 1) {
num = num.substring(0, num.length() - 1);
linklist.set(0, num);
result.setText(num);
} else {
linklist.removeLast();
result.setText("0");
}
} else if (linklist.size() == 3) {
String num = (String) linklist.getLast();
if (num.length() = 1) {
num = num.substring(0, num.length() - 1);
linklist.set(2, num);
result.setText(num);
} else {
linklist.removeLast();
result.setText("0");
}
}
} else if (e.getSource() == positiveminus) // 正负号按钮
{
if (linklist.size() == 1) {
String number1 = (String) linklist.getFirst();
try {
double d = Double.parseDouble(number1);
d = -1 * d;
String str = String.valueOf(d);
linklist.set(0, str);
result.setText(str);
} catch (Exception ee) {
}
} else if (linklist.size() == 3) {
String number2 = (String) linklist.getLast();
try {
double d = Double.parseDouble(number2);
d = -1 * d;
String str = String.valueOf(d);
linklist.set(2, str);
result.setText(str);
} catch (Exception ee) {
}
}
} else if (e.getSource() == reciprocal) // 求倒数按钮
{
if (linklist.size() == 1 || linklist.size() == 2) {
String number1 = (String) linklist.getFirst();
try {
double d = Double.parseDouble(number1);
d = 1.0 / d;
String str = String.valueOf(d);
linklist.set(0, str);
result.setText(str);
} catch (Exception ee) {
}
} else if (linklist.size() == 3) {
String number2 = (String) linklist.getLast();
try {
double d = Double.parseDouble(number2);
d = 1.0 / d;
String str = String.valueOf(d);
linklist.set(0, str);
result.setText(str);
} catch (Exception ee) {
}
}
} else if (e.getSource() == clear) // 清零按钮
{
pressequal = false;
result.setText("0");
linklist.clear();
}
}
public static void main(String args[]) {
new Calculator();
}
}
class NumberButton extends Button // 数字按钮类
{
int number;
public NumberButton(int number) // 构造方法
{
super("" + number);
this.number = number;
setForeground(Color.blue);
}
public int getNumber() {
return number;
}
}
class OperatorButton extends Button // 运算符号按钮类
{
String operator;
public OperatorButton(String operator) // 构造方法
{
super(operator);
this.operator = operator;
setForeground(Color.red);
}
public String getOperator() {
return operator;
}
}
String str = "12345";
str = str.substring(0, str.length()-1);
int a = Integer.parseInt(str);
以前写的，给你了
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) {}
}
}
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");
}
}
}