java编写的简单的计算器程序

1、精选优质文档-倾情为你奉上计算器项目内容：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，

2、以类的形式出现，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Button。 3. 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 cl

3、ass 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  JButto

4、n buttonBk, buttonCe, buttonC;  JButton button;  JButton buttonMC, buttonMR, buttonMS, buttonMAdd;  JButton buttonDot, buttonAddAndSub, buttonAdd, buttonSub, buttonMul,      buttonDiv, buttonMod;  JButton buttonSqrt, buttonDao, buttonEqual;  JMenu ed

5、itMenu, 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)&

6、#160; 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("

7、;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(2

8、55, 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 = n

9、ew 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");    copyIte

10、m.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

11、)");    tItem.addActionListener(this);    sItem = new JMenuItem("   科学型(S)");    sItem.addActionListener(this);    numberGroup = new JMenuItem("   数字分组(I)");    numberGroup.addActi

12、onListener(this);    viewMenu.add(tItem);    viewMenu.add(sItem);    viewMenu.add(numberGroup);    topHelp = new JMenuItem("   帮助主题(H)");    topHelp.addActionListener(this);    help = new JT

13、extArea(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“

14、/”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)"); 

15、0;  aboutCal.addActionListener(this);    helpMenu.add(topHelp);    helpMenu.add(aboutCal);    mainMenu.add(editMenu);    mainMenu.add(viewMenu);    mainMenu.add(helpMenu);    panel.add(mainMenu, BorderLayo

16、ut.NORTH);    panel.add(textAnswer, BorderLayout.CENTER);    panel.add(panel1, BorderLayout.SOUTH);    panel1.setLayout(new BorderLayout();    textMemory = new JTextField(3);    textMemory.setEditable(false);   

17、; textMemory.setBackground(new Color(217, 217, 217);    labelMemSpace = new JLabel("                   ");    buttonBk = new JButton("Backspace");  &#

18、160; 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);  

19、  buttonBk.addActionListener(this);    buttonCe.addActionListener(this);    buttonC.addActionListener(this);    panel1.add(panel2, BorderLayout.NORTH);    panel2.setLayout(new FlowLayout(FlowLayout.RIGHT);    panel2.add(

20、textMemory);    panel2.add(labelMemSpace);    panel2.add(buttonBk);    panel2.add(buttonCe);    panel2.add(buttonC);    panel3 = new JPanel();    panel1.add(panel3, BorderLayout.CENTER);    butto

21、n = new JButton10;    for (int i = 0; i < button.length; i+)       buttoni = new JButton(Integer.toString(i);      buttoni.setForeground(new Color(0, 0, 255);        buttonMC = new JButton("MC"

22、;);    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

23、, 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 JBut

24、ton("+/-");    buttonAddAndSub.setForeground(new Color(0, 0, 255);    buttonAdd = new JButton("+");    buttonAdd.setForeground(new Color(255, 0, 0);    buttonSub = new JButton("-");    buttonSub.

25、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);    bu

26、ttonMod = 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");  

27、  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(butto

28、nMC);    buttonMC.addActionListener(this);    panel3.add(button7);    button7.addActionListener(this);    panel3.add(button8);    button8.addActionListener(this);    panel3.add(button9);    butto

29、n9.addActionListener(this);    panel3.add(buttonDiv);    buttonDiv.addActionListener(this);    panel3.add(buttonSqrt);    buttonSqrt.addActionListener(this);    panel3.add(buttonMR);    buttonMR.addActionListen

30、er(this);    panel3.add(button4);    button4.addActionListener(this);    panel3.add(button5);    button5.addActionListener(this);    panel3.add(button6);    button6.addActionListener(this);    pa

31、nel3.add(buttonMul);    buttonMul.addActionListener(this);    panel3.add(buttonMod);    buttonMod.addActionListener(this);    panel3.add(buttonMS);    buttonMS.addActionListener(this);    panel3.add(button1);&#

32、160;   button1.addActionListener(this);    panel3.add(button2);    button2.addActionListener(this);    panel3.add(button3);    button3.addActionListener(this);    panel3.add(buttonSub);    buttonSub.a

33、ddActionListener(this);    panel3.add(buttonDao);    buttonDao.addActionListener(this);    panel3.add(buttonMAdd);    buttonMAdd.addActionListener(this);    panel3.add(button0);    button0.addActionListener(thi

34、s);    panel3.add(buttonAddAndSub);    buttonAddAndSub.addActionListener(this);    panel3.add(buttonDot);    buttonDot.addActionListener(this);    panel3.add(buttonAdd);    buttonAdd.addActionListener(this);

35、60;   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

36、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+)   

37、     if (temp = buttoni && 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

38、入'.'      if (temp = buttonDot && clickable = true)         boolean isDot = false;        if (textAnswer.getText().length() = 0)          isDot

39、= true;        for (int i = 0; i < textAnswer.getText().length(); i+)          if ('.' = textAnswer.getText().charAt(i)             isDot = true; 

40、60;          break;                  if (isDot = false)          textAnswer.setText(textAnswer.getText() + "."); &#

41、160;          if ( (temp = buttonAdd | temp = buttonSub | temp = buttonMul |            temp = buttonDiv) && clickable = true)         /'+'操作  &

42、#160;     if (temp = buttonAdd)           switch (prekey)             case 0:              answerd += Double.parseD

43、ouble(textAnswer.getText();              break;            case 1:              answerd -= Double.parseDouble(textA

44、nswer.getText();              break;            case 2:              answerd *= Double.parseDouble(textAnswer.getTe

45、xt();              break;            case 3:              if (Double.parseDouble(textAnswer.getText() = 0)  &#

46、160;              textAnswer.setText("除数不能为零");                clickable = false;           

47、60;                else                answerd /= Double.parseDouble(textAnswer.getText();           

48、;   break;            default:              answerd = Double.parseDouble(textAnswer.getText();             

49、60;      textAnswer.setText("");          prekey = key = 0;                /'-'操作        if (temp = buttonS

50、ub)           switch (prekey)             case 0:              answerd += Double.parseDouble(textAnswer.getText();   

51、60;          break;            case 1:              answerd -= Double.parseDouble(textAnswer.getText();     &#

52、160;        break;            case 2:              answerd *= Double.parseDouble(textAnswer.getText();       &

53、#160;      break;            case 3:              if (Double.parseDouble(textAnswer.getText() = 0)          &#

54、160;      textAnswer.setText("除数不能为零");                clickable = false;                    &#

55、160;       else                answerd /= Double.parseDouble(textAnswer.getText();              break;    

56、0;       default:              answerd = Double.parseDouble(textAnswer.getText();                    textAnswer.set

57、Text("");          prekey = key = 1;                /'*'操作        if (temp = buttonMul)        &#

58、160;  switch (prekey)             case 0:              answerd += Double.parseDouble(textAnswer.getText();           

59、60;  break;            case 1:              answerd -= Double.parseDouble(textAnswer.getText();              b

60、reak;            case 2:              answerd *= Double.parseDouble(textAnswer.getText();              break; 

61、           case 3:              if (Double.parseDouble(textAnswer.getText() = 0)                 textAnswer.se

62、tText("除数不能为零");                clickable = false;                            else

63、60;               answerd /= Double.parseDouble(textAnswer.getText();              break;            default:&

64、#160;             answerd = Double.parseDouble(textAnswer.getText();                    textAnswer.setText("");     

65、;     prekey = key = 2;                /'/'操作        if (temp = buttonDiv)           switch (prekey)    

66、60;        case 0:              answerd += Double.parseDouble(textAnswer.getText();              break;     &#

67、160;      case 1:              answerd -= Double.parseDouble(textAnswer.getText();              break;       &

68、#160;    case 2:              answerd *= Double.parseDouble(textAnswer.getText();              break;         

69、   case 3:              if (Double.parseDouble(textAnswer.getText() = 0)                 textAnswer.setText("除数不能为零");   

70、0;            clickable = false;                            else        

71、60;       answerd /= Double.parseDouble(textAnswer.getText();              break;            default:        &

72、#160;     answerd = Double.parseDouble(textAnswer.getText();                    textAnswer.setText("");          prekey = key = 3; 

73、;                   /'='操作      if (temp = buttonEqual && clickable = true)         /如果连续按'=',则进行连续运算      

74、;  if (prekey = 5)           if (key = 0)             answerd += vard;            textAnswer.setText(df.format(answerd);   &#

75、160;                if (key = 1)             answerd -= vard;            textAnswer.setText(df.format(answerd); 

76、60;                  if (key = 2)             answerd *= vard;            textAnswer.setText(df.format(answerd

77、);                    if (key = 3)             if (Double.parseDouble(textAnswer.getText() = 0)           

78、;    textAnswer.setText("除数不能为零");              clickable = false;                        else  

79、;             answerd /= vard;              textAnswer.setText(df.format(answerd);                &#

80、160;                     else           vard = Double.parseDouble(textAnswer.getText();          if (key = 0)  

81、0;          prekey = -1;            answerd += Double.parseDouble(textAnswer.getText();            textAnswer.setText(df.format(answerd); &#

82、160;                  if (key = 1)             prekey = -1;            answerd -= Double.parseDouble(textAnswe

83、r.getText();            textAnswer.setText(df.format(answerd);                    if (key = 2)           

84、  prekey = -1;            answerd *= Double.parseDouble(textAnswer.getText();            textAnswer.setText(df.format(answerd);         

85、60;         if (key = 3)             prekey = -1;            if (Double.parseDouble(textAnswer.getText() = 0)       

86、0;       textAnswer.setText("除数不能为零");              clickable = false;                     

87、0;  else               answerd /= Double.parseDouble(textAnswer.getText();              textAnswer.setText(df.format(answerd);      

88、60;                               prekey = 5;            /'%'操作，对第二个操作数除以100     

89、if (temp = buttonMod && clickable = true)         if (answerd = 0)           String s = textAnswer.getText();          textAnswer.setText(s);    &#

90、160;           else           boolean isDot = false;          for (int i = 0; i < textAnswer.getText().length(); i+)       

91、0;    if ('.' = textAnswer.getText().charAt(i)               isDot = true;              break;         

92、;             /如果是double数，除100          if (isDot = true)             double dtemp = Double.parseDouble(textAnswer.getText();   &#

93、160;        dtemp = dtemp / 100.0;            textAnswer.setText(Double.toString(dtemp);                    else  &

94、#160;          /如果是int数但能被100整除，则去掉末尾两个零            if (Integer.parseInt(textAnswer.getText() % 100 = 0)               int itemp = Inte

95、ger.parseInt(textAnswer.getText();              itemp /= 100;              textAnswer.setText(Integer.toString(itemp);        

96、0;               /如果是int数，但不能被100整除，则按double数处理            else               double dtemp = Double.parseDouble(tex

97、tAnswer.getText();              dtemp = dtemp / 100.0;              textAnswer.setText(Double.toString(dtemp);          

98、                                /开根号运算      if (temp = buttonSqrt && clickable = true)         St

99、ring s = textAnswer.getText();        if (s.charAt(0) = '-')           textAnswer.setText("负数不能开根号");          clickable = false;    

100、0;           else          textAnswer.setText(Double.toString(java.lang.Math.sqrt(Double.              parseDouble(textAnswer.getText(); 

101、60;          /倒数运算      if (temp = buttonDao && clickable = true)         if (textAnswer.getText().charAt(0) = '0' &&          

102、;  textAnswer.getText().length() = 1)           textAnswer.setText("零不能求倒数");          clickable = false;                else

103、           boolean isDec = true;          int i, j, k;          String s = Double.toString(1 / Double.parseDouble(textAnswer.getText();     

104、     for (i = 0; i < s.length(); i+)            if (s.charAt(i) = '.')              break;          for

105、(j = i + 1; j < s.length(); j+)            if (s.charAt(j) != '0')               isDec = false;            &#

106、160; break;                      if (isDec = true)             String stemp = ""         &

107、#160;  for (k = 0; k < i; k+)              stemp += s.charAt(k);            textAnswer.setText(stemp);            

108、60;       else            textAnswer.setText(s);                    /按下'+/-'按钮时处理      if (temp =

109、 buttonAddAndSub && clickable = true)         boolean isNumber = true;        String s = textAnswer.getText();        for (int i = 0; i < s.length(); i+)     &

110、#160;    if (! (s.charAt(i) >= '0' && s.charAt(i) <= '9' | s.charAt(i) = '.' |                 s.charAt(i) = '-')        

111、60;    isNumber = false;            break;                  if (isNumber = true)           /如果当前字符串首字母有&#

112、39;-'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;

113、 i < s.length(); i+)               char a = s.charAt(i);              textAnswer.setText(textAnswer.getText() + a);        

114、0;                       /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            textAnswer.setText(

115、'-' + s);                    /计算器有关内存操作      /'MC'的操作，将内存清0      if (temp = buttonMC && clickable = true)       

116、;  memoryd = memoryi = 0;        textMemory.setText("");            /'MS'的操作，将当前文本框内容保存入内存，显示'M'      if (temp = buttonMS && clickable = true)  &#

117、160;      boolean isDot = false;        textMemory.setText("   M");        for (int i = 0; i < textAnswer.getText().length(); i+)         

118、; if ('.' = textAnswer.getText().charAt(i)             isDot = true;            break;                 

119、; /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   &

120、#160;            /如果是int,则存入memoryi(int存储器)        else           memoryi = Integer.parseInt(textAnswer.getText();          memoryd = 0; /保证存储器中存放最新的值