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
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) {}
}
}
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);
}
}
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：
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");
}
}
}