Question

I am trying to develop a hex editor in which the panel for editor is provided with key listeners and the input through keyboard is converted into corresponding input. The problem however is regarding the saving the coverted input.only one key stroke value is converted at a time as for now. I would like to use this converted input() in a string as a bunch and use it for other purposes. I tried to save converted text in a byte array but it is returning the first value I typed irrespective of what the input afterwards is.

package gui.hex;

import javax.swing.*;

import cryptool.Test;

import java.awt.*;
import java.awt.event.*;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;

public class JHexEditorASCII extends JComponent implements MouseListener,
        KeyListener {

    private static final long serialVersionUID = 5636121664420538046L;
    private JHexEditor he;
    private static CharsetEncoder encoder = Charset.forName("UTF-8")
            .newEncoder();
    public static String modifiedText;
    public static byte temp[];

    public static byte[] getTemp() {
        return temp;
    }

    public void setTemp(byte[] temp) {
        this.temp = temp;
    }

    protected JHexEditorASCII(JHexEditor he) {
        this.he = he;
        addMouseListener(this);
        addKeyListener(this);
        addFocusListener(he);
    }

    public Dimension getPreferredSize() {
        debug("getPreferredSize()");
        return getMinimumSize();
    }

    public Dimension getMinimumSize() {
        debug("getMinimumSize()");

        Dimension d = new Dimension();
        FontMetrics fn = getFontMetrics(JHexEditor.font);
        int h = fn.getHeight();
        int nl = he.getLines();
        d.setSize((fn.stringWidth(" ") + 1) * (16) + (he.border * 2) + 1, h
                * nl + (he.border * 2) + 1);
        return d;
    }

    public void paint(Graphics g) {
        debug("paint(" + g + ")");
        debug("cursor=" + he.cursor + " buff.length=" + he.buff.length);
        Dimension d = getMinimumSize();

        // sets the color to the background.
        g.setColor(Color.orange);
        g.fillRect(0, 0, d.width, d.height);
        g.setColor(Color.black);

        g.setFont(JHexEditor.font);

        // ascii data
        int ini = he.getInitial() * 16;
        int fin = ini + (he.getLines() * 16);
        if (fin > he.buff.length)
            fin = he.buff.length;

        int x = 0;
        int y = 0;
        for (int n = ini; n < fin; n++) {
            if (n == he.cursor) {

                // sets color for the focus cursor it used to be in blue color.
                g.setColor(Color.red);
                if (hasFocus())
                    he.background(g, x, y, 1);
                else
                    he.table(g, x, y, 1);
                if (hasFocus())
                    g.setColor(Color.white);
                else
                    g.setColor(Color.black);
            } else {
                g.setColor(Color.black);
            }

            // builds a character object
            String s;

            if (encoder.isLegalReplacement(new byte[] { he.buff[n] }))
                s = "" + new Character((char) he.buff[n]);
            else
                s = ".";

            // compares the input supplied
            // if ((he.buff[n] < 20) || (he.buff[n] > 126))

            // converts the input entered into string
            // s = ".";
            // displaying of the text goes here.

            // displays the input

            System.out.println("the typed in string is:" + s);

            temp = s.getBytes();
            setTemp(temp);

            setModifiedText(s);

            he.printString(g, s, (x++), y);

            if (x == 16) {
                x = 0;
                y++;
            }
        }

    }

    private void debug(String s) {
        if (he.DEBUG)
            System.out.println("JHexEditorASCII ==> " + s);
    }

    public void dispaly(Graphics g) {
        int x = 0;
        int y = 0;

        he.printString(g, Test.getK(), (x++), y);
        if (x == 16) {
            x = 0;
            y++;
        }
    }

    // calculate the position of the mouse
    public int calculateMousePosition(int x, int y) {
        FontMetrics fn = getFontMetrics(JHexEditor.font);
        x = x / (fn.stringWidth(" ") + 1);
        y = y / fn.getHeight();
        debug("x=" + x + " ,y=" + y);
        return x + ((y + he.getInitial()) * 16);
    }

    // mouselistener
    public void mouseClicked(MouseEvent e) {
        if (e.getClickCount() == 2) {
            // double clicked
            he.setNewTextListener.actionPerformed(new ActionEvent(this, 0,
                    "NEWASCII"));
        }

        debug("mouseClicked(" + e + ")");
        he.cursor = calculateMousePosition(e.getX(), e.getY());
        this.requestFocus();
        he.repaint();
    }

    public void mousePressed(MouseEvent e) {
    }

    public void mouseReleased(MouseEvent e) {
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }

    // KeyListener
    public void keyTyped(KeyEvent e) {
        debug("keyTyped(" + e + ")");

        // only add content, if buffer is large enough
        if (he.buff.length > he.cursor) {
            he.buff[he.cursor] = (byte) e.getKeyChar();

            if (he.cursor != (he.buff.length - 1))
                he.cursor++;
            // change this
            // System.out.println( he.buff.toString());

            he.repaint();
        }
    }

    public void keyPressed(KeyEvent e) {
        debug("keyPressed(" + e + ")");
        he.keyPressed(e);
    }

    public void keyReleased(KeyEvent e) {
        debug("keyReleased(" + e + ")");
    }

    public boolean isFocusTraversable() {
        return true;
    }

    public static String getModifiedText() {
        return modifiedText;
    }

    public void setModifiedText(String modifiedText) {
        this.modifiedText = modifiedText;
    }
}

Answer 1

• develop a hex editor (encoder.isLegalReplacement...)

• use JTextField with DocumentFilter, or easiest could be JFormatterTextField instead of paint chars by using paint() to JComponent

• use paintComponent (instead of paint()) for Swing JComponents

• add DocumentListener to the JTextField with DocumentFilter or JFormatterTextField

• interesting way could be to built / prepare / create a ArrayList of hex () and to use AutoComplete JTextField