java编写的简单的计算器程序文件

1、计算器项目容： 编写一个 Applet ，模仿 windows 附件所带计算器的功能，可以帮助用户完成计 算功能，具体如下图所示。项目要求： 使用图形的方式借助窗口、菜单、按钮等标准界面元素和鼠标操作，来帮助用 户方便地向计算机系统发出命令， 启动操作， 并将系统运行的结果同样以图形的方式显示给 用户，这样更加直观和生动；1. Applet 容器中组件的添加与设置，包括面板以及菜单的使用；2. 容器中组件的布局管理；3. Java 核心包中数组、数学计算类的使用；4. 异常的处理；5. 事件处理模型中的三类对象的使用：1. Event- 事件，用户对界面操作在 java 语言上的描述，以类的形

2、式出现，例如键盘操作 对应的事件类是 KeyEvent 。2. Event Source- 事件源，事件发生的场所，通常就是各个组件，例如按钮 Button3. Event handler- 事件处理者，接收事件对象并对其进行处理的对象。6. 程序中事件处理的流程：1. 计算流程的细化参考代码：import java.awt.*;import java.lang.*;import javax.swing.*;import javax.swing.event.*;import java.awt.event.*;import java.text.DecimalFormat;public class

3、 Calculatorimplements 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;单纯做摆设，控制面板的形状JTextField textMemory;JLabel labelMemSpace; /labelMemSpaceJButton buttonBk, buttonCe, buttonC;JButton button;JButton buttonMC, buttonMR, but

4、tonMS, 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 cli

5、ckable; /控制当前能否按键double memoryd; /使用存中存储的数字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String copy; / 做复制用JTextArea help; / 帮助JScrollPane scrollHelp;/ 构造函数public Calculator() clickable = true;answerd =

6、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.setEditable(false);textAnswer.setBackground(new Color(255, 255, 255);panel = new JPanel();frame.getContentPane().add(panel);panel1 = new JPanel();panel2

7、= 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.addActio

8、nListener(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);view

9、Menu.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

10、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); pan

11、el.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); but

12、tonBk.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,

13、 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 JButton10;for (int i = 0; i button.length

14、; i+) buttoni = new JButton(Integer.toString(i); buttoni.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,

15、 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

16、 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

17、, 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.ad

18、d(buttonMC);buttonMC.addActionListener(this); panel3.add(button7);button7.addActionListener(this); panel3.add(button8);button8.addActionListener(this);panel3.add(button9); button9.addActionListener(this); panel3.add(buttonDiv); buttonDiv.addActionListener(this); panel3.add(buttonSqrt); buttonSqrt.ad

19、dActionListener(this); panel3.add(buttonMR); buttonMR.addActionListener(this);panel3.add(button4);button4.addActionListener(this);panel3.add(button5);button5.addActionListener(this);panel3.add(button6);button6.addActionListener(this);panel3.add(buttonMul); buttonMul.addActionListener(this); panel3.a

20、dd(buttonMod); buttonMod.addActionListener(this); panel3.add(buttonMS); buttonMS.addActionListener(this); panel3.add(button1);button1.addActionListener(this);panel3.add(button2);button2.addActionListener(this);panel3.add(button3); button3.addActionListener(this); panel3.add(buttonSub); buttonSub.add

21、ActionListener(this); panel3.add(buttonDao);buttonDao.addActionListener(this);panel3.add(buttonMAdd);buttonMAdd.addActionListener(this);panel3.add(button0);button0.addActionListener(this);panel3.add(buttonAddAndSub);buttonAddAndSub.addActionListener(this);panel3.add(buttonDot);buttonDot.addActionLis

22、tener(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

23、型数参与运算，是为 true ，不是为 falseObject 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 = buttoni & clickable = true) textAnswer.setText(textAnswer.getText() + Integer.toString(i);/ 按下.按钮时，判断当前文本框字符串中含不含 . ，如果已含，则不允许再插入 .if (temp = buttonDot & clickable = t

24、rue) 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

25、= 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

26、(Double.parseDouble(textAnswer.getText() = 0) textAnswer.setText( 除数不能为零 );clickable = false;elseanswerd /= 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:

27、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;elseanswe

28、rd /= 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(textAn

29、swer.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;elseanswerd /= Double.parseDouble(textAnswer.getText(); break;default:answerd = Double.parseDouble(textAnswer.

30、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 (Doub

31、le.parseDouble(textAnswer.getText() = 0) textAnswer.setText( 除数不能为零 );clickable = false;elseanswerd /= Double.parseDouble(textAnswer.getText(); break;default:answerd = Double.parseDouble(textAnswer.getText();textAnswer.setText();prekey = key = 3;/= 操作if (temp = buttonEqual & clickable = true) / 如果连续

32、按 =, 则进行连续运算if (prekey = 5) if (key = 0) answerd += vard;textAnswer.setText(df.format(answerd);if (key = 1) answerd -= vard;textAnswer.setText(df.format(answerd);if (key = 2) answerd *= vard;textAnswer.setText(df.format(answerd);if (key = 3) if (Double.parseDouble(textAnswer.getText() = 0) textAnswe

33、r.setText( 除数不能为零 ); clickable = false;else answerd /= vard;textAnswer.setText(df.format(answerd);else vard = Double.parseDouble(textAnswer.getText();if (key = 0) prekey = -1;answerd += Double.parseDouble(textAnswer.getText();textAnswer.setText(df.format(answerd);if (key = 1) prekey = -1;answerd -=

34、Double.parseDouble(textAnswer.getText();textAnswer.setText(df.format(answerd);if (key = 2) prekey = -1;answerd *= Double.parseDouble(textAnswer.getText();textAnswer.setText(df.format(answerd);if (key = 3) prekey = -1;if (Double.parseDouble(textAnswer.getText() = 0) textAnswer.setText( 除数不能为零 );click

35、able = false;else answerd /= Double.parseDouble(textAnswer.getText();textAnswer.setText(df.format(answerd);prekey = 5;/% 操作，对第二个操作数除以 100if (temp = buttonMod & clickable = true) if (answerd = 0) String s = textAnswer.getText();textAnswer.setText(s);else boolean isDot = false;for (int i = 0; i textAn

36、swer.getText().length(); i+)if (. = textAnswer.getText().charAt(i) isDot = true;break;/ 如果是 double 数，除 100if (isDot = true) double dtemp = Double.parseDouble(textAnswer.getText(); dtemp = dtemp / 100.0;textAnswer.setText(Double.toString(dtemp);else / 如果是 int 数但能被 100 整除，则去掉末尾两个零if (Integer.parseInt(

37、textAnswer.getText() % 100 = 0) int itemp = Integer.parseInt(textAnswer.getText();itemp /= 100;textAnswer.setText(Integer.toString(itemp);/ 如果是 int 数，但不能被 100 整除，则按 double 数处理 else double dtemp = Double.parseDouble(textAnswer.getText(); dtemp = dtemp / 100.0;textAnswer.setText(Double.toString(dtemp)

38、;/ 开根号运算if (temp = buttonSqrt & clickable = true) String s = textAnswer.getText();if (s.charAt(0) = -) textAnswer.setText( 负数不能开根号 );clickable = false;elsetextAnswer.setText(Double.toString(java.lang.Math.sqrt(Double. parseDouble(textAnswer.getText();/ 倒数运算if (temp = buttonDao & clickable = true) if

39、 (textAnswer.getText().charAt(0) = 0 &textAnswer.getText().length() = 1) textAnswer.setText( 零不能求倒数 );clickable = false;else boolean isDec = true;int i, j, k;String s = Double.toString(1 / Double.parseDouble(textAnswer.getText();for (i = 0; i s.length(); i+)if (s.charAt(i) = .)break;for (j = i + 1;

40、j s.length(); j+)if (s.charAt(j) != 0) isDec = false;break;if (isDec = true) String stemp = ;for (k = 0; k i; k+)stemp += s.charAt(k);textAnswer.setText(stemp);elsetextAnswer.setText(s);/ 按下 +/- 按钮时处理if (temp = buttonAddAndSub & clickable = true) boolean isNumber = true;String s = textAnswer.getText

41、();for (int i = 0; i = 0 & s.charAt(i) = 9 | s.charAt(i) = . |s.charAt(i) = -) isNumber = false;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) = -) textAnswer.setText();for (int i = 1; i s.length(); i+) char a = s.charAt(i);textAnswer.setText(textAnswer.getText(

42、) + 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elsetextAnswer.setText(- + s);/ 计算器有关存操作/MC 的操作，将存清 0if (temp = buttonMC & clickable = true) memoryd = memoryi = 0;textMemory.setText();/MS 的操作，将当前文本框容保存入存，显示 Mif (temp = buttonMS & clickable = true) boolean isDot = false;textMemory.setText( M);for (int i = 0; i

43、 textAnswer.getText().length(); i+)if (. = textAnswer.getText().charAt(i) isDot = true;break;/ 如果是 double, 则存入 memoryd(double 存储器 ) if (isDot = true) memoryd = Double.parseDouble(textAnswer.getText(); memoryi = 0; /保证存储器中存放最新的值/ 如果是 int, 则存入 memoryi(int 存储器 )else memoryi = Integer.parseInt(textAnswe

44、r.getText(); memoryd = 0; / 保证存储器中存放最新的值/MR 的操作，将存储器中的信息输出if (temp = buttonMR & clickable = true) if (memoryd != 0) textAnswer.setText(Double.toString(memoryd);if (memoryi != 0) textAnswer.setText(Integer.toString(memoryi);/M+ 的功能，将当前文本框里的数据和存储器中数据相加后，再存入存储器if (temp = buttonMAdd & clickable = true) boolean isDot = false;for (int i = 0; i textAnswer.getText().len