select text in jtextfield, but only when tabbing

[tormod eriksen]

I want to select all the text in JTextFields, but only when they are tabbed to.
I know how to select text, but not how to do it only when they gain focus by a tab from another component.

[Mahesh swami]

You can add a focus listener to the text field.And override foucsGained(FocusEvent).Then you can write the code of selecting the text in this method

[tormod eriksen]

I tried that, but haven't figured out how to check if it is tabbed to. Do you know how to do this?

[Brian Duff]

This is actually a bug in the Windows look and feel (it ought to behave like this by default)... Anyhoo, here's one way of solving it:
Rather than adding listeners directly to the field, instead change the caret implementation. The caret implementation is a mouse listener and a focus listener. You override the focus listening stuff to select all the text in the field, but in the mouse listening code, you save the current caret position before calling requestFocus() then reset the caret position after focus has been gained.
Something like this:

import java.awt.BorderLayout;
import java.awt.event.FocusEvent;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.text.DefaultCaret;
import javax.swing.text.JTextComponent;

class FixedCaret extends DefaultCaret
{
  public void mousePressed(MouseEvent e)
  {
    if (SwingUtilities.isLeftMouseButton(e))
    {
      positionCaret(e);
      JTextComponent component = getComponent();
      if (component.isEnabled() && !component.hasFocus())
      {
        // For editable text components, we perform some trickery...
        if (component.isEditable())
        {
          // first off, store the current caret position / selection:
          int savedDot = getDot();
          int savedMark = getMark();
          // Now request focus. This will cause all the text in the field to
          // be selected because of our focus listener...
          component.requestFocus();
          // So now we reset the caret back the way it should be:
          setDot(savedMark);
          moveDot(savedDot);
        }
        // On  non-editable text components always select all, even
        // when you mouse click into them...
        else
        {
          component.requestFocus();
        }
      }
    }
  }

  public void focusGained(FocusEvent e)
  {
    super.focusGained(e);
    // When focus is gained, select all the text
    int length = getComponent().getDocument().getLength();
    setDot(0);
    moveDot(length);
  }
  public static void main( String[] args )
  {
    try
    {
      UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName() );
    }
    catch (Exception e){}
    // Demo code
    // Note: this is all a bit messy. A better way to do this is to 
    // override the look and feel delegate class for TextFieldUI and
    // install the fixed caret into all text fields in the Windows
    // look and feel.
    JFrame f = new JFrame();
    JTextField tf1 = new JTextField();
    JTextField tf2 = new JTextField();
    int blinkRate = tf1.getCaret().getBlinkRate();
    FixedCaret fc1 = new FixedCaret();
    fc1.setBlinkRate( blinkRate );
    FixedCaret fc2 = new FixedCaret();
    fc2.setBlinkRate( blinkRate );
    tf1.setCaret( fc1 );
    tf2.setCaret( fc2 );
    f.getContentPane().setLayout( new BorderLayout() );
    f.getContentPane().add( tf1, BorderLayout.NORTH );
    f.getContentPane().add( tf2, BorderLayout.CENTER );
    f.pack();
    f.setVisible( true );
  }
}

Should do the trick
Brian
[ August 23, 2002: Message edited by: Brian Duff ]

[tormod eriksen]

Thanx, that really helped!
After some various tests I found one unexpected behaviour. When I set focus (tab or with mouse) to a JTextField that has set this FixedCaret, and in this JTextField's focusGained method calls jtextfieldobject.requestFocus(), focus is set to the jtextfieldobject, but the caret / selection is still visible in the first of these JTextFields.
When I set focus to another component via the gui, with tab or mouse, the caret / selection in the JTextField mentioned is set invisible.
Any idea why this is as it is?