asked on

Keystroke evaluation

Hi All,

I have the below code but I would like to limit people to typing in the characters in range A-E, so I need some kind of a key listener that will display a message if any other character is typed and will remove this character.

So if I typed AF it would say something like invalid character and the textfield would only have A remaining.

Thanks for any help

Damien

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.math.*;

public class Bullseye extends JFrame
{
      public char first;
      public char second;
      public char third;
      public int comScore=0;
      public int perScore=0;
      public int noOfTrys=0;

      JTextField textId = null;

      public static void main(String[] args)
     {
            JFrame frame = new Bullseye();
      frame.show();
     }

public Bullseye()
{
           //System.out.println("before chars");
           generateChars();
            //System.out.println("after chars");
           setSize(500, 100);
setTitle("Bullseye");
           addWindowListener(new WindowAdapter()
{
                  public void windowClosing(WindowEvent e)
{
                        System.exit(0);
}
}
            );

Container contentPane = getContentPane();
JPanel canvas = new JPanel();
             canvas.setLayout( new GridLayout(1,1,0,0));
             canvas.add(new JLabel("Enter 3 characters: "));
             textId = new JTextField();


             canvas.add(textId);
             contentPane.add(canvas, "Center");
JPanel p = new JPanel();
addButton(p, "Submit",
             new ActionListener()
      {
                   public void actionPerformed(ActionEvent evt)
{
                        evaluate();
}
}
             );

addButton(p, "Close",
new ActionListener()
{ public void actionPerformed(ActionEvent evt)
{
      System.exit(0);
}
});
contentPane.add(p, "South");
}

      public void addButton(Container c, String title,ActionListener a)
      {
            JButton b = new JButton(title);
       c.add(b);
       b.addActionListener(a);
     }

      private void generateChars()
      {
            boolean bEqual;
            first = convertToChar(Math.random());
            second = convertToChar(Math.random());
            third = convertToChar(Math.random());
            bEqual = true;

            while (bEqual)
            {
                  if (first == second)
                        second = convertToChar(Math.random());
                  else
                        bEqual = false;

                  //System.out.println("boolean = "+bEqual);
            }

            bEqual = true;
            while (bEqual)
            {
                  if ((first == third) || (second == third))
                        third = convertToChar(Math.random());
                  else
                        bEqual = false;
            }
            //This is only in for testing purposes
            System.out.println("New Combination :"+first+second+third);

      }

      private char convertToChar(double d)
      {
            //System.out.println("random number: "+d);
            int val = (new Double((d*5)+0.5)).intValue();
            //System.out.println("random int: "+val);
            switch(val)
            {
                  case 1:
                        return 'A';
                  case 2:
                        return 'B';
                  case 3:
                        return 'C';
                  case 4:
                        return 'D';
                  case 5:
                        return 'E';
                  default :
                        return 'A';
            }
      }

      private void evaluate()
      {
            try{
            noOfTrys++;
            String guess = textId.getText();
            guess = guess.toUpperCase();
            char a = guess.charAt(0);
            char b = guess.charAt(1);
            char c = guess.charAt(2);
            int[] intArray = compare(a,b,c);
            System.out.println("There is "+intArray[0]+" bullseye.");
            System.out.println("There is "+intArray[1]+" hits.");
            System.out.println("This is try "+noOfTrys);
            if (intArray[0]==3)
            {
                  perScore++;
                  noOfTrys=0;
                  System.out.println("You win!");
                  generateChars();

            }
            else
            {
                  if (noOfTrys==4)
                  {
                        comScore++;
                        noOfTrys=0;
                        System.out.println("You lose!");
                        generateChars();

                  }
            }
            System.out.println("Person : "+perScore);
            System.out.println("Computer : "+comScore);


            }
            catch(Exception e)
            {
                  System.out.println("Error in startSearch");
            }
      }

      private int[] compare(char a ,char b , char c)
      {
            int bullcount =0;
            int hitcount =0;
            if (a==first)
                  bullcount++;
            if (b==second)
                  bullcount++;
            if (c==third)
                  bullcount++;
            if ((a==second)||(a==third))
                  hitcount++;
            if ((b==first)||(b==third))
                  hitcount++;
            if ((c==second)||(c==first))
                  hitcount++;

            int[] result = new int[] {bullcount,hitcount};
            return result;
      }
}

ASKER CERTIFIED SOLUTION

bobbit31

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mzimmer74

Create a customTextField and overwrite the document model like this:

import java.awt.*;
import javax.swing.*;
import javax.swing.text.*;
import java.awt.Toolkit;
import java.awt.event.*;

public class CustomTextField extends JTextField
{
private Toolkit toolkit;

public CustomTextField(String text, int cols)
{
super(cols);
toolkit = Toolkit.getDefaultToolkit();
this.setText(text);
}
protected Document createDefaultModel()
{
return new CustomTextDocument();
}

protected class CustomTextDocument extends PlainDocument
{
public void insertString(int offs, String str, AttributeSet a)
throws BadLocationException
{
if(str != null && goodChar(str))
{
super.insertString(offs,str,a);
}
else
{
toolkit.beep();
}
}
}
}

You'll want to write the method goodChar(String s) to check to see that the string only contains the characters you want. Hope this helps.

m_onkey_boy

When checking for suitable characters, use a BitSet to do the checking, as it will perform MUCH better than any switch, if, or String manipulations...

private static final BitSet ALLOWED_CHARS = new BitSet(5);

static {
ALLOWED_CHARS .set('A');
ALLOWED_CHARS .set('B');
ALLOWED_CHARS .set('C');
ALLOWED_CHARS .set('D');
ALLOWED_CHARS .set('E');
}

public true isValidChar(char c){
return ALLOWED_CHARS.get(c)
}

yongsing

Adding a key listener to your text field is useless because the user can still copy-and-paste text (with other characters) onto your text field.

mzimmer74's solution is the way to go. By the way, in JDK1.4, there is a class called JFormattedField which I think will let you do what you want.

damienm

ASKER

I am not that familiar with Java but this is close enough.

Thanks

Damien