Keyboard Input

Question

http://www.rafb.net/paste/results/D3082433.html
In that link are all three of my classes (UserInterface.java, CalcEngine.java, and Calculator.java)
I'm trying to do keyboard input for the numbers, the decimal, all the operations and enter. But the way I have it set up, I can't get any of the methods in the CalcEngine.java to run once a button is pressed. It's hard for me the explain, but if you compile it and try looking at the code, you'll understand what I mean.
-sachit

Answer 1

Alright, I'll post the 3 classes here.
#### UserInterface.java ####
// Date Started: March 1, 2004
// Date Finished: March 26, 2004
// Program Description: A graphical user interface for the calculator.
//                              No calculation is being done here. This class is
//                              responsible just for putting up the display on
//                              screen. It then refers to the "CalcEngine" to do
//                              all the real work.
import java.awt.*;
import java.awt.event.*;
public class UserInterface implements KeyListener
     private CalcEngine calc;
     Frame panelFrame=new Frame("Non-Scientific Calculator");
     static Label displayLabel;
     static String button="";
     // Method Name: UserInterface()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: A user interface for the given calcEngine.
     public UserInterface()
          makeFrame();
          panelFrame.setVisible(true);
     // Method Name: setVisible()
     // Parameters Passed: boolean variable visible
     //     Data Returned: None
     //     Method Purpose: Sets the panalFrame interface visible.
public void setVisible(boolean visible)
          panelFrame.setVisible(visible);
     // Method Name: makeFrame()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: The full display of buttons and labels on the calculator.
     private void makeFrame()
          CalcEngine buttonHandler = new CalcEngine();
          Button[] myButtons=new Button[30];
          String[] labels={"","","BS","CE","C","PI","sin","cos","tan","%","sqrt","7","8","9","/","x�","4","5","6","x","1/x","1","2","3","-","-/+","0",".","=","+"};
          Font titleFont=new Font("Courier", Font.BOLD,20);
          Font buttonFont=new Font("Arial", Font.BOLD,13);
          String display="0";
          displayLabel=new Label(display);
          String info = buttonHandler.getInfo();
          Label infoLabel=new Label(info);
          //Labels all the buttons
          for(int i=0;i<myButtons.length;i++)
               myButtons=new Button(labels[i]);
          panelFrame.setLayout(new BorderLayout(4,5));
          panelFrame.setBackground(Color.gray);
               displayLabel.setFont(titleFont);
               displayLabel.setAlignment(Label.RIGHT);
               panelFrame.add("North",displayLabel);
          Panel secondPanel=new Panel();
          panelFrame.add("Center",secondPanel);
          secondPanel.setLayout(new GridLayout(6,5,5,2));
          secondPanel.setBackground(Color.gray);
               for(int i=0; i<myButtons.length; i++)
                    secondPanel.add(myButtons[i]);     
                    myButtons[i].setFont(buttonFont);
                    myButtons[i].addKeyListener(this);
                    myButtons[i].addActionListener(buttonHandler);
               myButtons[0].setBackground(Color.gray);
               myButtons[0].hide();
               myButtons[1].hide();
               panelFrame.add("South",infoLabel);
          panelFrame.resize(270,250);
          panelFrame.show();
     // Method Name: redisplay()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Updates the display of the current number being inputed.
     //                         Also truncates the decimal if it is ".0".
     public static void redisplay()
          boolean itsInt=false;
          int doubleChecker = (int)CalcEngine.getDisplayValue();
          int intValue=0;
          if(CalcEngine.getDisplayValue() == (float)doubleChecker)
               intValue=(int)Math.round(CalcEngine.getDisplayValue());
               itsInt=true;
          if(itsInt)
               displayLabel.setAlignment(Label.RIGHT);
               displayLabel.setText("" +intValue);
          else
               displayLabel.setAlignment(Label.RIGHT);
               displayLabel.setText("" + CalcEngine.getDisplayValue());
     public void keyTyped(KeyEvent e)
          char keyChar = e.getKeyChar();
          button=""+keyChar;
          CalcEngine calcEng= new CalcEngine();
          if(keyChar == '+')
               System.out.println("+ PRESSED!");
          else if(keyChar == '-')
               System.out.println("- PRESSED!");
          else if(keyChar == KeyEvent.VK_SLASH)
               System.out.println("/ PRESSED!");
          else if(keyChar == '*')
               System.out.println("x PRESSED!");
          else if(keyChar == KeyEvent.VK_1)
               System.out.println("1 PRESSED!");
          else if(keyChar == KeyEvent.VK_2)
               System.out.println("2 PRESSED!");
          else if(keyChar == KeyEvent.VK_3)
               System.out.println("3 PRESSED!");
          else if(keyChar == KeyEvent.VK_4)
               System.out.println("4 PRESSED!");
          else if(keyChar == KeyEvent.VK_5)
               System.out.println("5 PRESSED!");
          else if(keyChar == KeyEvent.VK_6)
               System.out.println("6 PRESSED!");
          else if(keyChar == KeyEvent.VK_7)
               System.out.println("7 PRESSED!");
          else if(keyChar == KeyEvent.VK_8)
               System.out.println("8 PRESSED!");
          else if(keyChar == KeyEvent.VK_9)
               System.out.println("9 PRESSED!");
          else if(keyChar == KeyEvent.VK_0)
               System.out.println("0 PRESSED!");
          else if(keyChar == KeyEvent.VK_ENTER || keyChar == KeyEvent.VK_EQUALS)
               calcEng.equals();
               System.out.println("= PRESSED!");          
          else if(keyChar == KeyEvent.VK_PERIOD)
               System.out.println(". PRESSED!");
          /*else
               /// QUESTION: what do these next two lines do?
               byte bytes[] = {(byte)keyChar};
               System.out.println(bytes);
               //     command = new String(bytes);
     public static String passButton()
          return button;
     public void keyPressed(KeyEvent e)
     public void keyReleased(KeyEvent e)
#### CalcEngine.java #####
// Date Started: March 1, 2004
// Date Finished: March 26, 2004
// Program Description: Does all the calculations for the calculator.
import java.awt.event.*;
import java.awt.*;
public class CalcEngine implements ActionListener
     final int ARRAY_SIZE=100;
     String []buttonPressed = new String[ARRAY_SIZE];
     String buttonCheck="";
     static String userDisplay="";
     int numberLength=0;
     int currentNumber=0;
     int previousNumber=0;
     int currentElement=0;
     boolean allowDecimal=true;
     boolean cEPressed=false;
     String buttonCheckKey;
     // Method Name: CalcEngine()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Instance of the CalcEngine.
     public CalcEngine()
          buttonCheckKey=UserInterface.passButton();
          buttonCheck=buttonCheckKey;
          System.out.println("ButtonCheckKey " +buttonCheck);
          if(buttonCheck=="=")
               if(currentElement>=2 && !buttonPressed[currentElement].equals(""))
                    equals();
          else if(buttonCheck.equals("C"))
               clear();
          else if(buttonCheck.equals("CE"))
               clearOne();
          else if(buttonCheck.equals("BS"))
               backSpace();
          else if(buttonCheck.equals("sqrt"))
               squareRoot();
          else if(buttonCheck.equals("sin") || buttonCheck.equals("cos") || buttonCheck.equals("tan"))
               trig(buttonCheck);
          else if(buttonCheck.equals("PI"))
               numPI();
          else if(buttonCheck.equals("1/x"))
               oneOver();
          else if(buttonCheck.equals("x�"))
               powerTwo();
          else if(buttonCheck.equals("-/+"))
               negPos();
          //else if(buttonCheck.equals("."))
          //     decimal(event);
          else if((buttonCheck.equals("+") || buttonCheck.equals("-") || buttonCheck.equals("x") || buttonCheck.equals("/") || buttonCheck.equals("%")) && !buttonPressed[currentElement].equals(""))
               operations(buttonCheck);
          //else     
          //     allNumbers(event);
          System.out.println("1st: "+buttonPressed[0]+ "\n2nd: " buttonPressed[1] "\n3rd: " buttonPressed[2] "\n4th: " buttonPressed[3] "\n5th: " +buttonPressed[4]);
          System.out.println("6th: "+buttonPressed[5]+ "\n7th: " buttonPressed[6] "\n8th: " buttonPressed[7] "\n9th: " buttonPressed[8]"\n");
     // Method Name: getDisplayValue()
     // Parameters Passed: None
     //     Data Returned: float variable N/A
     //     Method Purpose: Retrived the updated number to display on the calculator
     //                         and passes it as a double.
public static double getDisplayValue()
          return Double.valueOf(userDisplay).doubleValue();
     // Method Name: actionPerformed()
     // Parameters Passed: ActionEvent variable event
     //     Data Returned: None
     //     Method Purpose: Run the correct method depending on what button is pressed.
     public void actionPerformed(ActionEvent event/*, String button, boolean keyBoard*/)
          //Removes null from buttonPressed array
          for(int i=0; i<buttonPressed.length; i++)
               if(buttonPressed[i]==null)
                    buttonPressed[i]="";
          numberLength++;
          buttonCheck=event.getActionCommand();     //Gets the button that was pressed
          //Runs the correct method depending on which button is pressed
          if(buttonCheck=="=")
               if(currentElement>=2 && !buttonPressed[currentElement].equals(""))
                    equals();
          else if(buttonCheck.equals("C"))
               clear();
          else if(buttonCheck.equals("CE"))
               clearOne();
          else if(buttonCheck.equals("BS"))
               backSpace();
          else if(buttonCheck.equals("sqrt"))
               squareRoot();
          else if(buttonCheck.equals("sin") || buttonCheck.equals("cos") || buttonCheck.equals("tan"))
               trig(buttonCheck);
          else if(buttonCheck.equals("PI"))
               numPI();
          else if(buttonCheck.equals("1/x"))
               oneOver();
          else if(buttonCheck.equals("x�"))
               powerTwo();
          else if(buttonCheck.equals("-/+"))
               negPos();
          else if(buttonCheck.equals("."))
               decimal(event);
          else if((buttonCheck.equals("+") || buttonCheck.equals("-") || buttonCheck.equals("x") || buttonCheck.equals("/") || buttonCheck.equals("%")) && !buttonPressed[currentElement].equals(""))
               operations(buttonCheck);
          else     
               allNumbers(event);
          System.out.println("1st: "+buttonPressed[0]+ "\n2nd: " buttonPressed[1] "\n3rd: " buttonPressed[2] "\n4th: " buttonPressed[3] "\n5th: " +buttonPressed[4]);
          System.out.println("6th: "+buttonPressed[5]+ "\n7th: " buttonPressed[6] "\n8th: " buttonPressed[7] "\n9th: " buttonPressed[8]"\n");
     // Method Name: clear()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "C" button is pressed. Clears all the numbers
     //                         inputted into the calculator.
     public void clear()
          for(int i=0; i<buttonPressed.length; i++)
                    buttonPressed[i]="";
          userDisplay="0";
          currentElement=0;
          numberLength=0;
          UserInterface.redisplay();
     // Method Name: clearOne()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "CE" button is pressed. Deletes the last
     //                         entire number inputted into the calculator. For example,
     //                         if "5x123" was inputted, it would go back to "5x".
     public void clearOne()
          if(currentElement >= 2)
               buttonPressed[currentElement]="";
               userDisplay=buttonPressed[currentElement-2];
               numberLength=0;
               cEPressed=true;
               UserInterface.redisplay();
     // Method Name: backSpace()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "BS" button is pressed. Deletes the last
     //                         number inputted into the calculator. For example,
     //                         if "5x123" was inputted, it would go back to "5x12".
     public void backSpace()
               int stringSize=buttonPressed[currentElement].length();
               buttonPressed[currentElement] = userDisplay.substring(0, userDisplay.length() - 1);
               userDisplay=buttonPressed[currentElement];
               UserInterface.redisplay();
     // Method Name: trig()
     // Parameters Passed: String variable buttonCheck
     //     Data Returned: None
     //     Method Purpose: Is run if the "sin", "cos", or "tan" button is pressed.
     //                         Finds the sin, cos or tan of the current number.
     public void trig(String buttonCheck)
          if(buttonCheck.equals("sin"))
               double sinThisNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               double sinNum=Math.sin(sinThisNum);
               buttonPressed[currentElement]=""+sinNum;               
          else if(buttonCheck.equals("cos"))
               double cosThisNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               double cosNum=Math.cos(cosThisNum);
               buttonPressed[currentElement]=""+cosNum;                              
          else if(buttonCheck.equals("tan"))
               double tanThisNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               double tanNum=Math.tan(tanThisNum);
               buttonPressed[currentElement]=""+tanNum;                              
          userDisplay=buttonPressed[currentElement];
          UserInterface.redisplay();
     // Method Name: squareRoot()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "sqrt" button is pressed. Sqaures the current
     //                         number.
     public void squareRoot()
          if(currentElement==0 || currentElement % 2==0)
               double rootThisNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               double rootedNum=Math.sqrt(rootThisNum);
               buttonPressed[currentElement]=""+rootedNum;
               userDisplay=buttonPressed[currentElement];
               UserInterface.redisplay();
     // Method Name: numPI()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "PI" button is pressed. Allows the user to
     //                         input the value of PI.
     public void numPI()
          double PInumber=Math.PI;
          buttonPressed[currentElement]=""+PInumber;
          userDisplay=buttonPressed[currentElement];
          UserInterface.redisplay();
     // Method Name: oneOver()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "1/x" button is pressed. This will divide
     //                         the current number by 1.
     public void oneOver()
          if(currentElement==0 || currentElement % 2==0)
               double oneOverNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               oneOverNum=1/oneOverNum;
               buttonPressed[currentElement]=""+oneOverNum;
               userDisplay=buttonPressed[currentElement];
               UserInterface.redisplay();
     // Method Name: powerTwo()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "x^2" button is pressed. This will take the
     //                         current number to the power 2.
     public void powerTwo()
          if(currentElement==0 || currentElement % 2==0)
               double powNum=Double.valueOf(buttonPressed[currentElement]).doubleValue();
               powNum=Math.pow(powNum,2);
               buttonPressed[currentElement]=""+powNum;
               userDisplay=buttonPressed[currentElement];
               UserInterface.redisplay();
     // Method Name: negPos()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "-/+" button is pressed. Toggles the number
     //                         between a negative and positive value.
     public void negPos()
          if(userDisplay.charAt(0)!='-')
               userDisplay="-"+userDisplay;
          else
               userDisplay=userDisplay.substring(1);
          buttonPressed[currentElement]=userDisplay;
          UserInterface.redisplay();
     // Method Name: decimal()
     // Parameters Passed: ActionEvent variable event
     //     Data Returned: None
     //     Method Purpose: Is run if the "C" button is pressed. Clears all the numbers
     //                         inputted into the calculator.
     public void decimal(ActionEvent event)
          if(allowDecimal)
               buttonPressed[currentElement]+=event.getActionCommand();
               userDisplay+=event.getActionCommand();
               allowDecimal=false;
               UserInterface.redisplay();
     // Method Name: operations()
     // Parameters Passed: String variable buttonCheck
     //     Data Returned: None
     //     Method Purpose: Is run if the "+","-","x","/","%" button is pressed. Depending
     //                         on which operation is selected, the calculator will perform that.
     public void operations(String buttonCheck)
          currentElement++;
          if(buttonCheck.equals("+"))
               buttonPressed[currentElement]="+";
          else if(buttonCheck.equals("-"))
               buttonPressed[currentElement]="-";
          else if(buttonCheck.equals("x"))
               buttonPressed[currentElement]="x";
          else if(buttonCheck.equals("/"))
               buttonPressed[currentElement]="/";
          else if(buttonCheck.equals("%"))
               buttonPressed[currentElement]="%";
          currentElement++;
          numberLength=0;
          userDisplay="0";
          allowDecimal=true;               
     // Method Name: allNumbers()
     // Parameters Passed: ActionEvent variable event
     //     Data Returned: None
     //     Method Purpose: Is run if any of the numbers are pressed. Adds the inputted
     //                         number to the already ongoing number in the display.
     public void allNumbers(ActionEvent event)
          if(checkInt(event.getActionCommand()))
               if(cEPressed)
                    buttonPressed[currentElement]+=event.getActionCommand();
                    UserInterface.redisplay();
                    userDisplay=event.getActionCommand();
                    cEPressed=false;                         
                    UserInterface.redisplay();
               else
                    buttonPressed[currentElement]+=event.getActionCommand();
                    userDisplay+=event.getActionCommand();
                    UserInterface.redisplay();
     // Method Name: checkInt()
     // Parameters Passed: String variable dataInput
     //     Data Returned: None
     //     Method Purpose: A quick check to see if the button pressed is a number.
     //                         Rather than doing if(buttonCheck=="1") for every number.
     public boolean checkInt(String dataInput)
          try
               int n=Integer.parseInt(dataInput);
               return true;          
          catch (NumberFormatException nfe)
               return false;
     // Method Name: equals()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Is run if the "=" button is pressed. Takes all the inputted
     //                         numbers and operations and executes all the calculations.
     public void equals()
          double firstNum=0;
          double secondNum=0;
          double currentAns=0;
          int howBig=0;
          for(int i=0; i<buttonPressed.length;i+=2)
               if(buttonPressed[i]!="")
                    howBig++;
          firstNum=Double.valueOf(buttonPressed[0]).doubleValue();
          for(int j=0; j<=howBig-1; j+=2)
               secondNum=Double.valueOf(buttonPressed[j+2]).doubleValue();
               if(buttonPressed[j+1].equals("+"))
                    currentAns=firstNum+secondNum;
               else if(buttonPressed[j+1].equals("-"))
                    currentAns=firstNum-secondNum;
               else if(buttonPressed[j+1].equals("x"))
                    currentAns=firstNum*secondNum;
               else if(buttonPressed[j+1].equals("/"))
                    currentAns=firstNum/secondNum;
               else if(buttonPressed[j+1].equals("%"))
                    currentAns=firstNum%secondNum;
               firstNum=currentAns;     
          for(int i=0; i<buttonPressed.length; i++)
                    buttonPressed[i]="";
          buttonPressed[0]=""+currentAns;
          currentElement=0;
          userDisplay=""+currentAns;
          UserInterface.redisplay();
     // Method Name: getInfo()
     // Parameters Passed: None
     //     Data Returned: String variable N/A
     //     Method Purpose: Return the title of this calculation engine.
     public String getInfo()
          return "ver 0.9 Copyright � 2001-2003 Harish.";
### Calculator.java ###
// Date Started: March 1, 2004
// Date Finished: March 26, 2004
// Program Description: The main class of a simple calculator.
public class Calculator
     private CalcEngine engine;
     private UserInterface gui;
     // Method Name: Calculator()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: Creates the calculator and displays it on the screen.
     public Calculator()
          engine = new CalcEngine();
          gui = new UserInterface();
     // Method Name: show()
     // Parameters Passed: None
     //     Data Returned: None
     //     Method Purpose: If the window is closed, it will show it again.
     public void show()
          gui.setVisible(true);
     // Method Name: main()
     // Parameters Passed: String variable []args
     //     Data Returned: None
     //     Method Purpose: The main method that runs the Calculator()
     public static void main(String [] args)
          new Calculator();
-s64