西南科技大学Java实验计算器

package anjiajia; import java.awt.BorderLayout; 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.JPanel; import javax.swing.JTextField; public class Calculater extends JFrame implements ActionListener { private final String[] KEYS = { "7", "8", "9", "/", "1/x", "4", "5", "6", "*", "%", "1", "2", "3", "-", "√", "0", "+/-", ".", "+", "=" };//运算键 private final String[] COMMAND = { "Delete", "CE", "C" };//功能键 private final String[] M = { "M+", "MR", "MS", "MC" };//M键 //各个键的按钮设置 private JButton keys[] = new JButton[KEYS.length]; private JButton commands[] = new JButton[COMMAND.length]; private JButton m[] = new JButton[M.length]; private JTextField resultText = new JTextField("0");//文本 private boolean firstDigit = true;// 按的是否是整个表达式的第一个数字,或者是运算符后的第一个数字 private double resultNum = 0.0;// 计算的中间结果 private String operator = "=";// 当前运算的运算符 private boolean operateValidFlag = true; // 操作合法性 //构造函数 public Calculater() { super(); // 初始化计算器 init(); this.setBackground(Color.LIGHT_GRAY); this.setTitle("计算器"); this.setLocation(500, 300); this.setSize(500, 600); //this.setResizable(false); this.pack(); } //初始化计算器 private void init() { // 文本框中的内容采用右对齐方式 resultText.setHorizontalAlignment(JTextField.RIGHT); resultText.setEditable(false); resultText.setBackground(Color.LIGHT_GRAY); resultText.setFont(new Font("微软雅黑",Font.BOLD,32)); // 初始化计算器上键的按钮 JPanel calckeysPanel = new JPanel(); // 4行，5列的网格布局器，间隔为3个象素 calckeysPanel.setLayout(new GridLayout(4, 5, 3, 3)); for (int i = 0; i < KEYS.length; i++) { keys[i] = new JButton(KEYS[i]); calckeysPanel.add(keys[i]); keys[i].setFont(new Font("微软雅黑",Font.BOLD,20)); // 运算符键用蓝色标示，其他键用黑色表示 if(KEYS[i].matches("\\d*")) { keys[i].setForeground(Color.BLACK); } else keys[i].setForeground(Color.BLUE); } // keys[4].setFont(new Font("Adobe Gothic Std B",Font.BOLD,20));根号显示 JPanel commandsPanel = new JPanel(); // 1行，3列的网格布局器，间隔为3个象素 commandsPanel.setLayout(new GridLayout(1, 3, 3, 3)); for (int i = 0; i < COMMAND.length; i++) { commands[i] = new JButton(COMMAND[i]); commandsPanel.add(commands[i]); commands[i].setFont(new Font("微软雅黑",Font.BOLD,20)); commands[i].setForeground(Color.RED); } // 初始化M键 JPanel calmsPanel = new JPanel(); // 用网格布局管理器，5行，1列的网格，网格之间的水平方向间隔为3个象素，垂直方向间隔为3个象素 calmsPanel.setLayout(new GridLayout(4, 1, 3, 3)); for (int i = 0; i < M.length; i++) { m[i] = new JButton(M[i]); calmsPanel.add(m[i]); m[i].setFont(new Font("微软雅黑",Font.BOLD,20)); m[i].setForeground(Color.RED); } // 新建一个大画板 JPanel panel1 = new JPanel(); // 画板用边界布局管理器，组件之间间隔都为3象素 panel1.setLayout(new BorderLayout(3, 3)); panel1.add("North", commandsPanel); panel1.add("Center", calckeysPanel); // 文本框 JPanel top = new JPanel(); top.setLayout(new BorderLayout()); top.add("Center", resultText); // 整体布局 getContentPane().setLayout(new BorderLayout(3, 5)); getContentPane().add("North", top); getContentPane().add("Center", panel1); getContentPane().add("West", calmsPanel); // 为各按钮添加事件监听器 for (int i = 0; i < KEYS.length; i++) { keys[i].addActionListener(this); } for (int i = 0; i < COMMAND.length; i++) { commands[i].addActionListener(this); } for (int i = 0; i < M.length; i++) { m[i].addActionListener(this); } } public void actionPerformed(ActionEvent e) { // 获取事件源的标签 String label = e.getActionCommand(); if (label.equals(COMMAND[0])) { // "Backspace"键 handleBackspace(); } else if (label.equals(COMMAND[1])) { // "CE"键-纠错建 resultText.setText("0"); } else if (label.equals(COMMAND[2])) { // "C"键 handleC(); } else if ("0123456789.".indexOf(label) >= 0) { // 数字键或者小数点键 handleNumber(label); // handlezero(zero); } else { // 运算符键 handleOperator(label); } } //处理Backspace键的事件 private void handleBackspace() { String text = resultText.getText(); int i = text.length(); if (i > 0) { // 退格，将文本最后一个字符去掉 text = text.substring(0, i - 1); if (text.length() == 0) { resultText.setText("0"); firstDigit = true; operator = "="; } else { resultText.setText(text); } } } //处理数字键的事件 private void handleNumber(String key) { if (firstDigit) { // 输入的第一个数字 resultText.setText(key); } else if ((key.equals(".")) && (resultText.getText().indexOf(".") < 0)) { // 输入的是小数点，并且之前没有小数点，则将小数点附在结果文本框的后面 resultText.setText(resultText.getText() + "."); } else if (!key.equals(".")) { // 如果输入的不是小数点，则将数字附在结果文本框的后面 resultText.setText(resultText.getText() + key); } firstDigit = false; } //处理C键被按下的事件 private void handleC() { // 初始化计算器的各种值 resultText.setText("0"); firstDigit = true; operator = "="; } //处理运算符键被按下的事件 private void handleOperator(String key) { if (operator.equals("/")) { // 除法运算 if (getNumberFromText() == 0.0) { // 操作不合法 operateValidFlag = false; resultText.setText("除零错误"); } else { resultNum /= getNumberFromText(); } } else if (operator.equals("1/x")) { // 倒数运算 if (resultNum == 0.0) { // 操作不合法 operateValidFlag = false; resultText.setText("零没有倒数"); } else { resultNum = 1 / resultNum; } } else if (operator.equals("+")) {// 加法运算 resultNum += getNumberFromText(); } else if (operator.equals("-")) {// 减法运算 resultNum -= getNumberFromText(); } else if (operator.equals("*")) { // 乘法运算 resultNum *= getNumberFromText(); } else if (operator.equals("√")) {// 平方根运算 resultNum = Math.sqrt(resultNum); } else if (operator.equals("%")) {// 百分号运算，除以100 resultNum = resultNum / 100; } else if (operator.equals("+/-")) {// 正数负数运算 resultNum = resultNum * (-1); } else if (operator.equals("=")) {// 赋值运算 resultNum = getNumberFromText(); } if (operateValidFlag) {//浮点