Java编程实现计算器（三种）

package com.calculator.one; import java.awt.Color; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowEvent; import java.awt.event.WindowListener; import javax.swing.ImageIcon; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JTextField; import javax.swing.UIManager; public class Calculator implements ActionListener { /** * */ JFrame f = new JFrame(); JTextField tf = new JTextField("0."); JMenuBar bar = new JMenuBar(); JMenu menuEdit = new JMenu("编辑(E)"); JMenu menuView = new JMenu("查看(V)"); JMenu menuHelp = new JMenu("帮助(H)"); JMenuItem menuEditCopy = new JMenuItem("复制(C)"); JMenuItem menuEditPaste = new JMenuItem("粘贴(V)"); JMenuItem menuHelpAbout = new JMenuItem("关于计算器(A)"); JPanel panel0 = new JPanel(); JPanel panel2 = new JPanel(); JPanel panel = new JPanel(); JPanel panel3 = new JPanel(); JPanel panel4 = new JPanel(); JPanel panel5 = new JPanel(); JButton btBk = new JButton(" Backspace"); JButton btCe = new JButton("Ce"); JButton btCl = new JButton("C"); JButton bt7 = new JButton("7"); JButton bt8 = new JButton("8"); JButton bt9 = new JButton("9"); JButton btDiv = new JButton("/"); JButton btSqrt = new JButton("sqrt"); JButton bt4 = new JButton("4"); JButton bt5 = new JButton("5"); JButton bt6 = new JButton("6"); JButton btMult = new JButton("*"); JButton btMol = new JButton(" % "); JButton bt1 = new JButton("1"); JButton bt2 = new JButton("2"); JButton bt3 = new JButton("3"); JButton btMinu = new JButton("-"); JButton btCoun = new JButton(" 1/x"); JButton bt0 = new JButton("0"); JButton btPoint = new JButton("."); JButton btEqual = new JButton("="); JButton btAdd = new JButton("+"); JButton btSign = new JButton(" +/-"); /** * @param args */ public void init() { f.add(panel0); f.add(tf, "North"); f.setJMenuBar(bar); bar.add(menuEdit); bar.add(menuView); bar.add(menuHelp); menuEdit.add(menuEditCopy); menuEdit.add(menuEditPaste); menuHelp.add(menuHelpAbout); tf.setEditable(false);// 不可编辑 tf.setHorizontalAlignment(JTextField.RIGHT);// 从右侧输入数据 panel0.add(panel2); panel0.add(panel); panel0.add(panel3); panel0.add(panel4); panel0.add(panel5); panel2.setLayout(new GridLayout(1, 4)); panel2.add(btBk); panel2.add(btCe); panel2.add(btCl); panel.setLayout(new GridLayout(1, 5)); panel.add(bt7); panel.add(bt8); panel.add(bt9); panel.add(btDiv); panel.add(btSqrt);// 根号 panel3.setLayout(new GridLayout(1, 5)); panel3.add(bt4); panel3.add(bt5); panel3.add(bt6); panel3.add(btMult); panel3.add(btMol);// 百分号 panel4.setLayout(new GridLayout(1, 5)); panel4.add(bt1); panel4.add(bt2); panel4.add(bt3); panel4.add(btMinu); panel4.add(btCoun);// 倒数 panel5.setLayout(new GridLayout(1, 5)); panel5.add(bt0); panel5.add(btPoint); panel5.add(btAdd); panel5.add(btEqual); panel5.add(btSign);// 正负符号 btBk.setForeground(new Color(255, 0, 0)); btCe.setForeground(new Color(255, 0, 0)); btCl.setForeground(new Color(255, 0, 0)); btAdd.setForeground(new Color(255, 0, 0)); btMult.setForeground(new Color(255, 0, 0)); btDiv.setForeground(new Color(255, 0, 0)); btMinu.setForeground(new Color(255, 0, 0)); btEqual.setForeground(new Color(255, 0, 0)); bt0.setForeground(new Color(0, 0, 255)); bt1.setForeground(new Color(0, 0, 255)); bt2.setForeground(new Color(0, 0, 255)); bt3.setForeground(new Color(0, 0, 255)); bt4.setForeground(new Color(0, 0, 255)); bt5.setForeground(new Color(0, 0, 255)); bt6.setForeground(new Color(0, 0, 255)); bt7.setForeground(new Color(0, 0, 255)); bt8.setForeground(new Color(0, 0, 255)); bt9.setForeground(new Color(0, 0, 255)); btSqrt.setForeground(new Color(0, 0, 255)); btMol.setForeground(new Color(0, 0, 255)); btCoun.setForeground(new Color(0, 0, 255)); btSign.setForeground(new Color(0, 0, 255)); // 注册监听 bt1.addActionListener(this); bt2.addActionListener(this); bt3.addActionListener(this); bt4.addActionListener(this); bt5.addActionListener(this); bt6.addActionListener(this); bt7.addActionListener(this); bt8.addActionListener(this); bt9.addActionListener(this); bt0.addActionListener(this); btAdd.addActionListener(this); btMinu.addActionListener(this); btMult.addActionListener(this); btDiv.addActionListener(this); btEqual.addActionListener(this); btPoint.addActionListener(this); btSqrt.addActionListener(this); btMol.addActionListener(this); btCoun.addActionListener(this); btSign.addActionListener(this); btBk.addActionListener(this); btCe.addActionListener(this); btCl.addActionListener(this); menuEditCopy.addActionListener(this); menuEditPaste.addActionListener(this); menuHelpAbout.addActionListener(this); f.addWindowListener(new MyWinLis()); f.setTitle("计算器"); f.setSize(295, 240); f.setResizable(false);// 不能改变窗体大小 f.setVisible(true); } String foreNum = null; String currOpr = null; String currNum = null; boolean i = true; String copy;// 复制 public void actionPerformed(ActionEvent e) { // TODO 自动生成方法存根 Object obj = e.getSource(); // 输入数字 if (obj == bt1 || obj == bt2 || obj == bt3 || obj == bt4 || obj == bt5 || obj == bt6 || obj == bt7 || obj == bt8 || obj == bt9 || obj == bt0) { if (i == true) tf.setText(e.getActionCommand()); else tf.setText(tf.getText() + e.getActionCommand()); i = false; } // 小数点 else if (obj == btPoint) { if (i == false) tf.setText(tf.getText() + '.'); } // 实现开根号 else if (obj == btSqrt) { if (tf.getText().charAt(0) == '-') { tf.setText("函数输入无效"); } else tf.setText(Double.toString(java.lang.Math.sqrt(Double .parseDouble(tf.getText())))); i = true; } // 实现倒数 else if (obj == btCoun) { if (tf.getText().charAt(0) == '0') { tf.setText("零不能求倒数"); i = true; } else { String s = Double .toString(1 / Double.parseDouble(tf.getText())); foreNum = tf.getText(); tf.setText(s); i = true; } } // 实现+/-符号 else if (obj == btSign) { boolean isNumber = true; String s = tf.getText(); for (int m = 0; m < s.length(); m++) if (!(s.charAt(m) >= '0' && s.charAt(m) <= '9' || s.charAt(m) == '.' || s.charAt(m) == '-')) { break; } if (isNumber == true) { // 如果当前字符串首字母有-号,代表现在是个负数,再按下时,则将首符号去掉 if (s.charAt(0) == '-') { tf.setText(""); for (int m = 1; m < s.length(); m++) { char a = s.charAt(m); tf.setText(tf.getText() + a); } } // 如果当前字符串第一个字符不是符号，则添加一个符号在首字母处 else tf.setText('-' + s); } } // 实现%功能 else if (obj == btMol) { boolean isNumber = true; if (isNumber == true) tf.setText(String .valueOf(Double.parseDouble(tf.getText()) / 100)); else tf.setText("错误"); } // 实现符号运算 else if (obj == btAdd || obj == btMinu || obj == btDiv || obj == btMult) { if (i == false) { currNum = tf.getText(); if (currOpr == "+") tf.setText(String.valueOf(Double.parseDouble(foreNum) + Double.parseDouble(currNum))); else if (currOpr == "-") tf.setText(String.valueOf(Double.parseDouble(f