calculator.java

计算器程序

import java.awt.*;
import java.lang.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;
import java.text.DecimalFormat;
public class Calculator
implements ActionListener 
{ 
	//导入动作监听接口
	//设计面板中的单位
	JFrame frame;
	JTextField textAnswer;
	JPanel panel, panel1, panel2, panel3;
	JMenuBar mainMenu;
	JTextField textMemory;
  	JLabel labelMemSpace; //labelMemSpace单纯做摆设，控制面板的形状
  	JButton buttonBk, buttonCe, buttonC;
  	JButton button[];
  	JButton buttonMC, buttonMR, buttonMS, buttonMAdd;
  	JButton buttonDot, buttonAddAndSub, buttonAdd, buttonSub, buttonMul,buttonDiv, buttonMod;
  	JButton buttonSqrt, buttonDao, buttonEqual;
  	JMenu editMenu, viewMenu, helpMenu;
  	JMenuItem copyItem, pasteItem, tItem, sItem, numberGroup, topHelp, aboutCal;
  	DecimalFormat df; //设置数据输出精度
  	boolean clickable; //控制当前能否按键
  	double memoryd; //使用内存中存储的数字
  	int memoryi;
  	double vard, answerd; //用来保存double型数据的中间值(vard)和最后结果(answerd)
  	short key = -1, prekey = -1; //key用来保存当前进行何种运算,prekey用来保存前次进行何种运算
  	String copy; //做复制用
  	JTextArea help; //帮助
  	JScrollPane scrollHelp;
  	//构造函数
  	public Calculator() 
  	{
		clickable = true;
		answerd = 0;
		frame = new JFrame("计算器");
		df = new DecimalFormat("0.##############"); //设置数据输出精度(对于double型值)
		textAnswer = new JTextField(15);
		textAnswer.setText("");
		textAnswer.setHorizontalAlignment(JTextField.RIGHT); 
		textAnswer.setEditable(false);
		textAnswer.setBackground(new Color(255, 255, 255));
		panel = new JPanel();
		frame.getContentPane().add(panel);
		panel1 = new JPanel();
		panel2 = new JPanel();
		panel.setLayout(new BorderLayout());
		//设计整个面板
		mainMenu = new JMenuBar();
		editMenu = new JMenu("编辑(E)");
		viewMenu = new JMenu("查看(V)");
		helpMenu = new JMenu("帮助(H)");
		copyItem = new JMenuItem("   复制(C) Ctrl+C");
		copyItem.addActionListener(this);
		pasteItem = new JMenuItem("   粘贴(V) Ctrl+V");
		pasteItem.addActionListener(this);
		editMenu.add(copyItem);
		editMenu.add(pasteItem);
		tItem = new JMenuItem("●标准型(T)");
		tItem.addActionListener(this);
		sItem = new JMenuItem("   科学型(S)");
		sItem.addActionListener(this);
		numberGroup = new JMenuItem("   数字分组(I)");
		numberGroup.addActionListener(this);
		viewMenu.add(tItem);
		viewMenu.add(sItem);
		viewMenu.add(numberGroup);
		topHelp = new JMenuItem("   帮助主题(H)");
		topHelp.addActionListener(this);
		help = new JTextArea(5, 20);
		scrollHelp = new JScrollPane(help);
		help.setEditable(false);
		help.append("执行简单计算\n");
		help.append("1.  键入计算的第一个数字。\n");
	    help.append("2.  单击“+”执行加、“-”执行减、“*”执行乘或“/”执行除。\n");
	    help.append("3.  键入计算的下一个数字。\n");
	    help.append("4.  输入所有剩余的运算符和数字。\n");
	    help.append("5.  单击“=”。\n");
	    aboutCal = new JMenuItem("   关于计算器(A)");
	    aboutCal.addActionListener(this);
	    helpMenu.add(topHelp);
	    helpMenu.add(aboutCal);
	    mainMenu.add(editMenu);
	    mainMenu.add(viewMenu);
	    mainMenu.add(helpMenu);
	    panel.add(mainMenu, BorderLayout.NORTH);
	    panel.add(textAnswer, BorderLayout.CENTER);
	    panel.add(panel1, BorderLayout.SOUTH);
	    panel1.setLayout(new BorderLayout());
	    textMemory = new JTextField(3);
	    textMemory.setEditable(false);
	    textMemory.setBackground(new Color(217, 217, 217));
	    labelMemSpace = new JLabel("                   ");
	    buttonBk = new JButton("Backspace");
	    buttonBk.setForeground(new Color(255, 0, 0));
	    buttonCe = new JButton("CE");
	    buttonCe.setForeground(new Color(255, 0, 0));
	    buttonC = new JButton("C");
	    buttonC.setForeground(new Color(255, 0, 0));
	    buttonBk.addActionListener(this);
	    buttonCe.addActionListener(this);
	    buttonC.addActionListener(this);
	    panel1.add(panel2, BorderLayout.NORTH);
	    panel2.setLayout(new FlowLayout(FlowLayout.RIGHT));
	    panel2.add(textMemory);
	    panel2.add(labelMemSpace);
	    panel2.add(buttonBk);
	    panel2.add(buttonCe);
	    panel2.add(buttonC);
	    panel3 = new JPanel();
	    panel1.add(panel3, BorderLayout.CENTER);
	    button = new JButton[10];
	    for (int i = 0; i < button.length; i++) 
	 	{
			button[i] = new JButton(Integer.toString(i));
			button[i].setForeground(new Color(0, 0, 255));
    	}
		buttonMC = new JButton("MC");
	    buttonMC.setForeground(new Color(255, 0, 0));
	    buttonMR = new JButton("MR");
	    buttonMR.setForeground(new Color(255, 0, 0));
	    buttonMS = new JButton("MS");
	    buttonMS.setForeground(new Color(255, 0, 0));
	    buttonMAdd = new JButton("M+");
	    buttonMAdd.setForeground(new Color(255, 0, 0));
	    buttonDot = new JButton(".");
	    buttonDot.setForeground(new Color(0, 0, 255));
	    buttonAddAndSub = new JButton("+/-");
	    buttonAddAndSub.setForeground(new Color(0, 0, 255));
	    buttonAdd = new JButton("+");
	    buttonAdd.setForeground(new Color(255, 0, 0));
	    buttonSub = new JButton("-");
	    buttonSub.setForeground(new Color(255, 0, 0));
	    buttonMul = new JButton("*");
	    buttonMul.setForeground(new Color(255, 0, 0));
	    buttonDiv = new JButton("/");
	    buttonDiv.setForeground(new Color(255, 0, 0));
	    buttonMod = new JButton("%");
	    buttonMod.setForeground(new Color(0, 0, 255));
	    buttonSqrt = new JButton("sqrt");
	    buttonSqrt.setForeground(new Color(0, 0, 255));
	    buttonDao = new JButton("1/x");
	    buttonDao.setForeground(new Color(0, 0, 255));
	    buttonEqual = new JButton("=");
	    buttonEqual.setForeground(new Color(255, 0, 0));
	    //将所有行为与监听绑定
	    panel3.setLayout(new GridLayout(4, 6));
	    panel3.add(buttonMC);
	    buttonMC.addActionListener(this);
	    panel3.add(button[7]);
	    button[7].addActionListener(this);
	    panel3.add(button[8]);
	    button[8].addActionListener(this);
	    panel3.add(button[9]);
	    button[9].addActionListener(this);
	    panel3.add(buttonDiv);
	    buttonDiv.addActionListener(this);
	    panel3.add(buttonSqrt);
	    buttonSqrt.addActionListener(this);
	    panel3.add(buttonMR);
	    buttonMR.addActionListener(this);
	    panel3.add(button[4]);
	    button[4].addActionListener(this);
	    panel3.add(button[5]);
	    button[5].addActionListener(this);
	    panel3.add(button[6]);
	    button[6].addActionListener(this);
	    panel3.add(buttonMul);
	    buttonMul.addActionListener(this);
	    panel3.add(buttonMod);
	    buttonMod.addActionListener(this);
	    panel3.add(buttonMS);
	    buttonMS.addActionListener(this);
	    panel3.add(button[1]);
	    button[1].addActionListener(this);
	    panel3.add(button[2]);
	    button[2].addActionListener(this);
	    panel3.add(button[3]);
	    button[3].addActionListener(this);
	    panel3.add(buttonSub);
	    buttonSub.addActionListener(this);
	    panel3.add(buttonDao);
	    buttonDao.addActionListener(this);
	    panel3.add(buttonMAdd);
	    buttonMAdd.addActionListener(this);
	    panel3.add(button[0]);
	    button[0].addActionListener(this);
	    panel3.add(buttonAddAndSub);
	    buttonAddAndSub.addActionListener(this);
	    panel3.add(buttonDot);
	    buttonDot.addActionListener(this);
	    panel3.add(buttonAdd);
	    buttonAdd.addActionListener(this);
	    panel3.add(buttonEqual);
	    buttonEqual.addActionListener(this);
	    frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
	    frame.pack();
	    frame.show();
  	}
  	//设置各个按钮行为
  	public void actionPerformed(ActionEvent event) 
  	{
		boolean sign = false; //判断是否是double型数参与运算，是为true，不是为false
	    Object temp = event.getSource();
	    try 
	    {
      		//如果按下数据按钮，将按下的按钮代表的数据插入的当前文本框字符串之后
     		for (int i = 0; i <= 9; i++)
       		if (temp == button[i] && clickable == true)
        	textAnswer.setText(textAnswer.getText() + Integer.toString(i));
          	//按下'.'按钮时，判断当前文本框内字符串中含不含'.'，如果已含，则不允许再插入'.'
      		if (temp == buttonDot && clickable == true) 
      		{
        		boolean isDot = false;
        		if (textAnswer.getText().length() == 0)
          		isDot = true;
        		for (int i = 0; i < textAnswer.getText().length(); i++)
          		if ('.' == textAnswer.getText().charAt(i)) 
          		{
           			isDot = true;
           			break;
          		}
        		if (isDot == false)
          		textAnswer.setText(textAnswer.getText() + ".");
      		}
      		if ( (temp == buttonAdd || temp == buttonSub || temp == buttonMul ||
           	temp == buttonDiv) && clickable == true)
           	{
        		//'+'操作
        		if (temp == buttonAdd) 
        		{
          			switch (prekey) 
          			{
           				case 0:
           				answerd += Double.parseDouble(textAnswer.getText());
           				break;
           				case 1:
           	 			answerd -= Double.parseDouble(textAnswer.getText());
           				break;
           				case 2:
              			answerd *= Double.parseDouble(textAnswer.getText());
              			break;
            			case 3:
              			if (Double.parseDouble(textAnswer.getText()) == 0) 
              			{
                			textAnswer.setText("除数不能为零");
                			clickable = false;
              			}
              			else
                		answerd /= Double.parseDouble(textAnswer.getText());
              			break;
            			default:
              			answerd = Double.parseDouble(textAnswer.getText());
          			}
         			textAnswer.setText("");
          			prekey = key = 0;
        		}
        		//'-'操作
        		if (temp == buttonSub) 
        		{
          			switch (prekey) 
          			{
            			case 0:
              			answerd += Double.parseDouble(textAnswer.getText());
              			break;
            			case 1:
              			answerd -= Double.parseDouble(textAnswer.getText());
              			break;
            			case 2:
              			answerd *= Double.parseDouble(textAnswer.getText());
              			break;
            			case 3:
              			if (Double.parseDouble(textAnswer.getText()) == 0) 
              			{
                			textAnswer.setText("除数不能为零");
                			clickable = false;
              			}
              			else
                		answerd /= Double.parseDouble(textAnswer.getText());
              			break;
            			default:
              			answerd = Double.parseDouble(textAnswer.getText());
          			}
          			textAnswer.setText("");
          			prekey = key = 1;
        		}
        		//'*'操作
        		if (temp == buttonMul) 
        		{
          			switch (prekey) 
          			{
            			case 0:
              			answerd += Double.parseDouble(textAnswer.getText());
             	 		break;
            			case 1:
              			answerd -= Double.parseDouble(textAnswer.getText());
              			break;
            			case 2:
              			answerd *= Double.parseDouble(textAnswer.getText());
              			break;
            			case 3:
              			if (Double.parseDouble(textAnswer.getText()) == 0) 
              			{
                			textAnswer.setText("除数不能为零");
                			clickable = false;
              			}
              			else
                		answerd /= Double.parseDouble(textAnswer.getText());
             	 		break;
            			default:
              			answerd = Double.parseDouble(textAnswer.getText());
          			}
          			textAnswer.setText("");
         			prekey = key = 2;
        		}
        		//'/'操作
        		if (temp == buttonDiv) 
        		{
          			switch (prekey) 
          			{
            			case 0:
              			answerd += Double.parseDouble(textAnswer.getText());
              			break;
            			case 1:
              			answerd -= Double.parseDouble(textAnswer.getText());
              			break;
            			case 2:
              			answerd *= Double.parseDouble(textAnswer.getText());
              			break;
            			case 3:
              			if (Double.parseDouble(textAnswer.getText()) == 0) 
              			{
                			textAnswer.setText("除数不能为零");
                			clickable = false;
              			}