一、计算机模型
二、源代码
import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.util.Vector; import java.math.BigDecimal; public class Calculator { // 操作数1，为了程序的安全，初值一定设置，这里我们设置为0。 String str1 = "0"; // 操作数2 String str2 = "0"; // 运算符 String signal = "+"; // 运算结果 String result = ""; // 以下k1至k2为状态开关 // 开关1用于选择输入方向，将要写入str1或str2 int k1 = 1; // 开关2用于记录符号键的次数，如果 k2>1 说明进行的是 2+3-9+8 这样的多符号运算 int k2 = 1; // 开关3用于标识 str1 是否可以被清0 ，等于1时可以，不等于1时不能被清0 int k3 = 1; // 开关4用于标识 str2 是否可以被清0 int k4 = 1; // 开关5用于控制小数点可否被录入，等于1时可以，不为1时，输入的小数点被丢掉 int k5 = 1; // store的作用类似于寄存器，用于记录是否连续按下符号键 JButton store; @SuppressWarnings("rawtypes") Vector vt = new Vector(20, 10); // 声明各个UI组件对象并初始化 JFrame frame = new JFrame("Calculator"); JTextField result_TextField = new JTextField(result, 20); JButton clear_Button = new JButton("Clear"); JButton button0 = new JButton("0"); JButton button1 = new JButton("1"); JButton button2 = new JButton("2"); JButton button3 = new JButton("3"); JButton button4 = new JButton("4"); JButton button5 = new JButton("5"); JButton button6 = new JButton("6"); JButton button7 = new JButton("7"); JButton button8 = new JButton("8"); JButton button9 = new JButton("9"); JButton button_Dian = new JButton("."); JButton button_jia = new JButton("+"); JButton button_jian = new JButton("-"); JButton button_cheng = new JButton("*"); JButton button_chu = new JButton("/"); JButton button_dy = new JButton("="); // 计算机类的构造器 public Calculator() { // 为按钮设置等效键，即可以通过对应的键盘按键来代替点击它 button0.setMnemonic(KeyEvent.VK_0); // 其它等效键省略，你可以自行补充完整 // 设置文本框为右对齐，使输入和结果都靠右显示 result_TextField.setHorizontalAlignment(JTextField.RIGHT); // 将UI组件添加进容器内 JPanel pan = new JPanel(); pan.setLayout(new GridLayout(4, 4, 5, 5)); pan.add(button7); pan.add(button8); pan.add(button9); pan.add(button_chu); pan.add(button4); pan.add(button5); pan.add(button6); pan.add(button_cheng); pan.add(button1); pan.add(button2); pan.add(button3); pan.add(button_jian); pan.add(button0); pan.add(button_Dian); pan.add(button_dy); pan.add(button_jia); pan.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); JPanel pan2 = new JPanel(); pan2.setLayout(new BorderLayout()); pan2.add(result_TextField, BorderLayout.WEST); pan2.add(clear_Button, BorderLayout.EAST); // 设置主窗口出现在屏幕上的位置 frame.setLocation(300, 200); // 设置窗体不能调大小 frame.setResizable(false); frame.getContentPane().setLayout(new BorderLayout()); frame.getContentPane().add(pan2, BorderLayout.NORTH); frame.getContentPane().add(pan, BorderLayout.CENTER); frame.pack(); frame.setVisible(true); // 事件处理程序 // 数字键 class Listener implements ActionListener { @SuppressWarnings("unchecked") public void actionPerformed(ActionEvent e) { String ss = ((JButton) e.getSource()).getText(); store = (JButton) e.getSource(); vt.add(store); if (k1 == 1) { if (k3 == 1) { str1 = ""; // 还原开关k5状态 k5 = 1; } str1 = str1 + ss; k3 = k3 + 1; // 显示结果 result_TextField.setText(str1); } else if (k1 == 2) { if (k4 == 1) { str2 = ""; // 还原开关k5状态 k5 = 1; } str2 = str2 + ss; k4 = k4 + 1; result_TextField.setText(str2); } } } // 输入的运算符号的处理 class Listener_signal implements ActionListener { @SuppressWarnings("unchecked") public void actionPerformed(ActionEvent e) { String ss2 = ((JButton) e.getSource()).getText(); store = (JButton) e.getSource(); vt.add(store); if (k2 == 1) { // 开关 k1 为 1 时向数 1 写输入值，为2时向数2写输入值。 k1 = 2; k5 = 1; signal = ss2; k2 = k2 + 1;// 按符号键的次数 } else { int a = vt.size(); JButton c = (JButton) vt.get(a - 2); if (!(c.getText().equals("+")) && !(c.getText().equals("-")) && !(c.getText().equals("*")) && !(c.getText().equals("/"))) { cal(); str1 = result; // 开关 k1 为 1 时，向数 1 写值，为2时向数2写 k1 = 2; k5 = 1; k4 = 1; signal = ss2; } k2 = k2 + 1; } } } // 清除键的逻辑（Clear） class Listener_clear implements ActionListener { @SuppressWarnings("unchecked") public void actionPerformed(ActionEvent e) { store = (JButton) e.getSource(); vt.add(store); k5 = 1; k2 = 1; k1 = 1; k3 = 1; k4 = 1; str1 = "0"; str2 = "0"; signal = ""; result = ""; result_TextField.setText(result); vt.clear(); } } // 等于键的逻辑 class Listener_dy implements ActionListener { @SuppressWarnings("unchecked") public void actionPerformed(ActionEvent e) { store = (JButton) e.getSource(); vt.add(store); cal(); // 还原各个开关的状态 k1 = 1; k2 = 1; k3 = 1; k4 = 1; str1 = result; } } // 小数点的处理 class Listener_xiaos implements ActionListener { @SuppressWarnings("unchecked") public void actionPerformed(ActionEvent e) { store = (JButton) e.getSource(); vt.add(store); if (k5 == 1) { String ss2 = ((JButton) e.getSource()).getText(); if (k1 == 1) { if (k3 == 1) { str1 = ""; // 还原开关k5状态 k5 = 1; } str1 = str1 + ss2; k3 = k3 + 1; // 显示结果 result_TextField.setText(str1); } else if (k1 == 2) { if (k4 == 1) { str2 = ""; // 还原开关k5的状态 k5 = 1; } str2 = str2 + ss2; k4 = k4 + 1; result_TextField.setText(str2); } } k5 = k5 + 1; } } // 注册各个监听器，即绑定事件响应逻辑到各个UI组件上 Listener_dy jt_dy = new Listener_dy(); // 监听数字键 Listener jt = new Listener(); // 监听符号键 Listener_signal jt_signal = new Listener_signal(); // 监听清除键 Listener_clear jt_c = new Listener_clear(); // 监听小数点键 Listener_xiaos jt_xs = new Listener_xiaos(); button7.addActionListener(jt); button8.addActionListener(jt); button9.addActionListener(jt); button_chu.addActionListener(jt_signal); button4.addActionListener(jt); button5.addActionListener(jt); button6.addActionListener(jt); button_cheng.addActionListener(jt_signal); button1.addActionListener(jt); button2.addActionListener(jt); button3.addActionListener(jt); button_jian.addActionListener(jt_signal); button0.addActionListener(jt); button_Dian.addActionListener(jt_xs); button_dy.addActionListener(jt_dy); button_jia.addActionListener(jt_signal); clear_Button.addActionListener(jt_c); // 窗体关闭事件的响应程序 frame.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); } // 计算逻辑 public void cal() { // 操作数1 double a2; // 操作数2 double b2; // 运算符 String c = signal; // 运算结果 double result2 = 0; if (c.equals("")) { result_TextField.setText("Please input operator"); } else { // 手动处理小数点的问题 if (str1.equals(".")) str1 = "0.0"; if (str2.equals(".")) str2 = "0.0"; a2 = Double.valueOf(str1).doubleValue(); b2 = Double.valueOf(str2).doubleValue(); if (c.equals("+")) { result2 = a2 + b2; } if (c.equals("-")) { result2 = a2 - b2; } if (c.equals("*")) { BigDecimal m1 = new BigDecimal(Double.toString(a2)); BigDecimal m2 = new BigDecimal(Double.toString(b2)); result2 = m1.multiply(m2).doubleValue(); } if (c.equals("/")) { if (b2 == 0) { result2 = 0; } else { result2 = a2 / b2; } } result = ((new Double(result2)).toString()); result_TextField.setText(result); } } @SuppressWarnings("unused") public static void main(String[] args) { // 设置程序显示的界面风格，可以去除 try { UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel"); } catch (Exception e) { e.printStackTrace(); } Calculator cal = new Calculator(); } }