import java.awt.*;
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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;
}
}
跟小数没有关系啊，+ - * /
把2个数都设置成double类型的，
或者float类型的就可以了。
如果我理解的不对，请指出。
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：
if(temp==".")//判断只能输入一个小数，这个放在actionPerformed里的\x0d\x0a{\x0d\x0a for(int i=0;i
回答于 2022-11-16
重庆分公司
重庆分公司
