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JAVA计算器【源码】

 
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    1. import javax.microedition.midlet.*;
    3. import javax.microedition.lcdui.*;
    3. /**
    4. * 该类是应用程序的主类，控制应用程序的生命周期。
    5. */
    6. public class CalcMIDlet extends MIDlet implements CommandListener {
    7. //
    8. private CalcForm calcForm;
    9. private Command cmdExit = new Command("退出", Command.EXIT, 1);
    11. public void startApp() {
    12. Display display = Display.getDisplay(this);
    13. calcForm = new CalcForm();
    14. calcForm.addCommand(cmdExit);
    15. calcForm.setCommandListener(this);
    16. display.setCurrent(calcForm);
    17. }
    19. public void pauseApp() {
    20. //
    21. }
    23. public void destroyApp(boolean unconditional) {
    24. //
    25. }
    27. public void commandAction(Command cmd, Displayable d) {
    28. if(cmd == cmdExit) {
    29. notifyDestroyed();
    30. }
    31. }
    32. }
    Java代码
    1. import javax.microedition.lcdui.*;
    3. /**
    4. * 该类描述了计算器。
    5. * 实现了计算器的界面，及加、减、乘、除等计算功能。
    6. */
    7. public class CalcForm extends Form implements CalcKeyboardListener { //
    8. private CalcScreen showArea; //计算器的显示区
    9. private CalcKeyboard ckeyboard; //计算器键盘
    11. private boolean hasNewOperand = false; //有新的操作数
    12. private boolean numInputing = false;
    13. private double acc = 0.0; //累加器
    14. private String operator = ""; //运算符
    15. private double operand = 0.0; //操作数
    17. public CalcForm() {
    18. super("计算器");
    19. showArea = new CalcScreen(); //创建计算器的显示区对象
    20. ckeyboard = new CalcKeyboard(4, 5); //创建计算器的键盘
    21. ckeyboard.setCalcKeyboardListener(this); //
    23. //布局
    24. showArea.setLayout(Item.LAYOUT_2|Item.LAYOUT_CENTER|Item.LAYOUT_NEWLINE_AFTER);
    25. append(showArea);
    26. append(new Spacer(this.getWidth(), 5));
    27. ckeyboard.setLayout(Item.LAYOUT_2|Item.LAYOUT_CENTER);
    28. append(ckeyboard);
    30. reset();
    31. }
    33. //按钮单击事件处理方法
    34. //如果设备支持触摸屏功能，当用户使用笔在按钮上单击后，
    35. //注册在键盘上的监视器将调用下面的方法，对单击事件进行处理。
    36. public void actionPerformmed(CalcKeyboard btn, String symbol) {
    37. if(symbol == CalcKeyboard.NUM_ZERO || symbol == CalcKeyboard.NUM_ONE || symbol == CalcKeyboard.NUM_TWO ||
    38. symbol == CalcKeyboard.NUM_THREE ||symbol == CalcKeyboard.NUM_FOUR ||symbol == CalcKeyboard.NUM_FIVE ||
    39. symbol == CalcKeyboard.NUM_SIX ||symbol == CalcKeyboard.NUM_SEVEN ||symbol == CalcKeyboard.NUM_EIGHT ||
    40. symbol == CalcKeyboard.NUM_NINE ) {
    41. //
    42. inputNum(symbol);
    43. }
    44. else if(symbol == CalcKeyboard.SYMBOL_DOT
    45. && showArea.getText().indexOf(CalcKeyboard.SYMBOL_DOT) == -1) {
    46. //
    47. inputNum(symbol);
    48. }
    49. else if(symbol == CalcKeyboard.BACKSPACE) {
    50. String text = showArea.getText();
    51. if(text.length() > 0) {
    52. text = text.substring(0, text.length()-1);
    53. showArea.setText(text);
    54. }
    55. }
    56. else if(symbol == CalcKeyboard.CE) {
    57. showArea.setText("0.");
    58. }
    59. else if(symbol == CalcKeyboard.C) {
    60. //计算器归零
    61. reset();
    62. }
    63. else if(symbol == CalcKeyboard.ADD || symbol == CalcKeyboard.MINUS ||
    64. symbol == CalcKeyboard.MULT || symbol == CalcKeyboard.DIVIDE ||
    65. symbol == CalcKeyboard.EQUALS) {
    66. //
    67. numInputing = false;
    68. String s = showArea.getText();
    69. double d = Double.parseDouble(s);
    70. jisuan(d, symbol);
    71. showArea.setText(String.valueOf(acc));
    72. }
    73. else if(symbol == CalcKeyboard.SYMBOL_MINUS) {
    74. String str = showArea.getText();
    75. if(str.charAt(0) == '-') {
    76. showArea.setText(str.substring(1, str.length()));
    77. }
    78. else {
    79. showArea.setText("-" + str);
    80. }
    81. }
    82. }
    84. private void jisuan(double exp, String oper) {
    85. if(operator.equals("")) {
    86. acc = exp;
    87. operand = exp;
    88. }
    89. else {
    90. if(hasNewOperand) { //新的操作数
    91. operand = exp;
    92. if(operator.equals(CalcKeyboard.ADD)) {
    93. acc += operand;
    94. }
    95. else if(operator.equals(CalcKeyboard.MINUS)) {
    96. acc -= operand;
    97. }
    98. else if(operator.equals(CalcKeyboard.MULT)) {
    99. acc *= operand;
    100. }
    101. else if(operator.equals(CalcKeyboard.DIVIDE)) {
    102. acc /= operand;
    103. }
    105. }
    106. else {
    107. if(oper.equals(CalcKeyboard.EQUALS)) {
    108. if(operator.equals(CalcKeyboard.ADD)) {
    109. acc += operand;
    110. }
    111. else if(operator.equals(CalcKeyboard.MINUS)) {
    112. acc -= operand;
    113. }
    114. else if(operator.equals(CalcKeyboard.MULT)) {
    115. acc *= operand;
    116. }
    117. else if(operator.equals(CalcKeyboard.DIVIDE)) {
    118. acc /= operand;
    119. }
    120. if(!oper.equals(CalcKeyboard.EQUALS)) {
    121. operator = oper;
    122. }
    123. }
    124. }
    125. }
    126. if(!oper.equals(CalcKeyboard.EQUALS)) {
    127. operator = oper;
    128. }
    129. hasNewOperand = false;
    130. }
    132. private void reset() {
    133. hasNewOperand = false;
    134. numInputing = false;
    135. acc = 0.0;
    136. operator = "";
    137. showArea.setText("0.");
    138. }
    140. private void inputNum(String str) {
    141. if(numInputing) {
    142. showArea.setText(showArea.getText() + str);
    143. }
    144. else {
    145. showArea.setText(str);
    146. numInputing = true;
    147. }
    148. hasNewOperand = true;
    149. }
    150. }
    Java代码
    1. import javax.microedition.lcdui.*;
    3. /**
    4. * 该类描述了计算器键盘。提供了直观的图形用户界面，该类支持触摸屏功能。
    5. */
    6. public class CalcKeyboard extends CustomItem {
    7. public static final String BACKSPACE = "<-";
    8. public static final String CE = "CE";
    9. public static final String C = "C";
    10. public static final String SYMBOL_MINUS = "+/-";
    11. public static final String NUM_ZERO = "0";
    12. public static final String NUM_ONE = "1";
    13. public static final String NUM_TWO = "2";
    14. public static final String NUM_THREE = "3";
    15. public static final String NUM_FOUR = "4";
    16. public static final String NUM_FIVE = "5";
    17. public static final String NUM_SIX = "6";
    18. public static final String NUM_SEVEN = "7";
    19. public static final String NUM_EIGHT = "8";
    20. public static final String NUM_NINE = "9";
    21. public static final String SYMBOL_DOT = ".";
    22. public static final String ADD = "+";
    23. public static final String MINUS = "-";
    24. public static final String MULT = "*";
    25. public static final String DIVIDE = "/";
    26. public static final String EQUALS = "=";
    28. private static final int PRESSED = 0;
    29. private static final int RELEASED = 1;
    31. private CalcKeyboardListener ckListener; //指针动作监视器
    32. private Font textFont;
    33. private int col; //列
    34. private int row; //行
    35. private int btnWidth; //按键宽
    36. private int btnHeight; //按键高
    37. private int hSpace = 4; //按键水平间距
    38. private int vSpace = 4; //按键垂直间距
    40. private int keyState = RELEASED;
    42. private String[] keyLabel = {
    43. BACKSPACE, CE, C, SYMBOL_MINUS,
    44. NUM_SEVEN, NUM_EIGHT, NUM_NINE, DIVIDE,
    45. NUM_FOUR, NUM_FIVE, NUM_SIX, MULT,
    46. NUM_ONE, NUM_TWO, NUM_THREE, MINUS,
    47. NUM_ZERO, SYMBOL_DOT, EQUALS, ADD
    48. };
    50. public CalcKeyboard(int col, int row) {
    51. super(null);
    52. textFont = Font.getFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_LARGE);
    53. this.col = col;
    54. this.row = row;
    55. btnHeight = textFont.getHeight() + 4;
    56. btnWidth = btnHeight + 10;
    57. }
    59. protected int getMinContentHeight() {
    60. return row * (btnHeight + vSpace) - vSpace;
    61. }
    63. protected int getMinContentWidth() {
    64. return col * (btnWidth + hSpace) - hSpace;
    65. }
    67. protected int getPrefContentHeight(int width) {
    68. return getMinContentHeight();
    69. }
    71. protected int getPrefContentWidth(int height) {
    72. return getMinContentWidth();
    73. }
    75. protected void paint(Graphics g, int w, int h) {
    76. for(int i=0; i<keyLabel.length; i++) {
    77. drawButton(g, keyLabel[i], i%col * (btnWidth+hSpace), i/col*(btnHeight+vSpace), btnWidth, btnHeight);
    78. }
    79. }
    81. private void drawButton(Graphics g, String str, int x, int y, int w, int h) {
    82. g.setColor(160, 160, 255);
    83. g.drawRect(x, y, w-1, h-1);
    84. if(keyState == RELEASED) {
    85. g.setColor(240, 240, 255);
    86. }
    87. else if(keyState == PRESSED) {
    88. g.setColor(210, 210, 255);
    89. }
    90. g.fillRect(x+2, y+2, w-4, h-4);
    92. g.setColor(0, 0, 0);
    93. g.setFont(textFont);
    94. g.drawString(str, x+w/2, y+h, Graphics.BOTTOM|Graphics.HCENTER);
    95. }
    97. private int getIndex(int x, int y) {
    98. int j = x / (btnWidth+hSpace);
    99. int i = y / (btnHeight+vSpace);
    101. return (col*i)+j;
    102. }
    104. //指针事件处理方法
    105. //如果当前设备支持触摸屏功能,当用户使用笔在屏幕上按下时,
    106. //系统将调用该方法。
    107. protected void pointerPressed(int x, int y) {
    108. keyState = PRESSED;
    109. int ax = x - x % (btnWidth+hSpace);
    110. int ay = y - y % (btnHeight+vSpace);
    111. repaint(ax, ay, btnWidth, btnHeight);
    112. }
    114. //指针事件处理方法
    115. //如果当前设备支持触摸屏功能,当用户使用笔在屏幕上按下,然后释放时,
    116. //系统将调用该方法。
    117. protected void pointerReleased(int x, int y) {
    118. keyState = RELEASED;
    119. int ax = x - x % (btnWidth+hSpace);
    120. int ay = y - y % (btnHeight+vSpace);
    121. repaint(ax, ay, btnWidth, btnHeight);
    122. if(ckListener != null) {
    123. int index = getIndex(x, y);
    124. ckListener.actionPerformmed(this, keyLabel[index]);
    125. }
    126. }
    128. //为当前计算器键盘设置监视器
    129. public void setCalcKeyboardListener(CalcKeyboardListener ckListener) {
    130. this.ckListener = ckListener;
    131. }
    132. }
    135. /**
    136. * 该接口描述了计算器键盘的监视器，定义了计算器键盘按钮单击动作
    137. * 的处理方法。
    138. */
    139. public interface CalcKeyboardListener {
    140. //指针单击动作的处理方法。
    141. //如果设备支持触摸屏功能，当用户使用笔单击屏幕上计算盘键盘上的按钮
    142. //时，监视该键盘的监视器将回调该方法，处理单击动作。
    143. //参数ck表示被监视的计算器键盘，symbol表示键盘上的按键。
    144. public void actionPerformmed(CalcKeyboard ck, String symbol);
    145. }
    Java代码
    1. import javax.microedition.lcdui.*;
    3. /**
    4. * 该类描述了计算器的显示区，用于显示输入的操作数及计算结果。
    5. */
    6. public class CalcScreen extends CustomItem {
    7. private String text;
    8. private Font showFont;
    10. public CalcScreen() {
    11. super(null);
    12. showFont = Font.getFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_LARGE);
    13. text = "";
    14. }
    16. protected int getMinContentHeight() {
    17. return showFont.getHeight() + 4;
    18. }
    20. protected int getMinContentWidth() {
    21. return showFont.stringWidth("012345678901234.-") + 4;
    22. }
    24. protected int getPrefContentHeight(int width) {
    25. return getMinContentHeight();
    26. }
    28. protected int getPrefContentWidth(int height) {
    29. return 150;
    30. }
    32. protected void paint(Graphics g, int w, int h) {
    33. g.setColor(160, 160, 255);
    34. g.drawRect(0, 0, w-1, h-1);
    35. g.setColor(210, 210, 255);
    36. g.drawRect(2, 2, w-5, h-5);
    38. g.setColor(0, 0, 0);
    39. g.setFont(showFont);
    40. g.drawString(text, w-10, h-3, Graphics.BOTTOM|Graphics.RIGHT);
    41. }
    43. public void setText(String text) {
    44. this.text = text;
    45. repaint();
    46. }
    48. public String getText() {
    49. return text;
    50. }
    51. }
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| bug满天飞的工作心得(2012.08.10)
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