jTextField in overtype/overstrike

Here is a class that allows you to toggle between insert/overtype mode in a JTextArea by extending JTextArea:

http://www.discoverteenergy.com/files/OvertypeTextArea.java

JTextField, JEditorPane, JTextPane could be extended in the same way to provide insert/overtype functionality.

Does anybody know of a way you can provide this functionality for all the JTextComponent classes without extending each class individually?

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.text.*;

import javax.swing.event.*;

import javax.swing.plaf.*;

public class OvertypeTextArea extends JTextArea

{

private static Toolkit toolkit = Toolkit.getDefaultToolkit();

private static boolean isInsertMode;

private Caret defaultCaret;

private Caret overtypeCaret;

public OvertypeTextArea(int row, int column)

{

super(row, column);

setCaretColor( Color.red );

defaultCaret = getCaret();

overtypeCaret = new OvertypeCaret();

overtypeCaret.setBlinkRate( defaultCaret.getBlinkRate() );

setInsertMode( false );

}

/*

*Return the insert/overtype mode

*/

public boolean isInsertMode()

{

return isInsertMode;

}

/*

*Set the caret to use depending on insert/overtype mode

*/

public void setInsertMode(boolean isInsertMode)

{

this.isInsertMode = isInsertMode;

int pos = getCaretPosition();

if (isInsertMode())

{

setCaret( defaultCaret );

}

else

{

setCaret( overtypeCaret );

}

setCaretPosition( pos );

}

/*

* Override method from JComponent

*/

public void replaceSelection(String text)

{

// Implement overtype mode by selecting the character at the current

// caret position

if ( ! isInsertMode() )

{

int pos = getCaretPosition();

if (getSelectedText() == null

&& pos < getDocument().getLength())

{

moveCaretPosition( pos + 1);

}

}

super.replaceSelection(text);

}

/*

* Override method from JComponent

*/

protected void processKeyEvent(KeyEvent e)

{

super.processKeyEvent(e);

// Handle release of Insert key to toggle insert/overtype mode

if (e.getID() == KeyEvent.KEY_RELEASED

&& e.getKeyCode() == KeyEvent.VK_INSERT)

{

setInsertMode( ! isInsertMode() );

}

}

/*

* Paint a horizontal line the width of a column and 1 pixel high

*/

class OvertypeCaret extends DefaultCaret

{

/*

* The overtype caret will simply be a horizontal line one pixel high

* (once we determine where to paint it)

*/

public void paint(Graphics g)

{

if (isVisible())

{

try

{

JTextComponent component = getComponent();

TextUI mapper = component.getUI();

Rectangle r = mapper.modelToView(component, getDot());

g.setColor(component.getCaretColor());

int width = g.getFontMetrics().charWidth( 'w' );

int y = r.y + r.height - 2;

g.drawLine(r.x, y, r.x + width - 1, y);

}

catch (BadLocationException e) {}

}

}

/*

* Damage must be overridden whenever the paint method is overridden

* (The damaged area is the area the caret is painted in. We must

* consider the area for the default caret and this caret)

*/

protected synchronized void damage(Rectangle r)

{

if (r != null)

{

JTextComponent component = getComponent();

x = r.x;

y = r.y;

width = component.getFontMetrics( component.getFont() ).charWidth( 'w' );

height = r.height;

repaint();

}

}

}

public static void main(String[] args)

{

JFrame frame = new JFrame();

frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

OvertypeTextArea textArea= new OvertypeTextArea(5,20);

textArea.setFont( new Font("monospaced", Font.PLAIN, 12) );

textArea.setText("abcdefg");

frame.getContentPane().add( textArea );

frame.pack();

frame.setVisible(true);

}

}

camickr at 2007-7-2 3:09:59 >