i have a textarea which filled with comments that uers entered.
the problem is that i do not want to allow the user to touch the previuos comments since i save each time all the text to the comments field in DB.
I currently use 2 text areas but i want to merge them into 1 text area.
> Or, depening on your exact requirement, you may want
> to try a NavigationFilter
>
> http://forum.java.sun.com/thread.jspa?forumID=57&threa
> dID=5132843&start=10
it's working ONLY FOR MOVEMENTS WITH ARROWS but when pressing back space it is going to the area which should not be altered
Actually a DocumentFilter won't work either, since no characters are being added to the Document.
So it looks like you need to create a custom backspace action. Something like this:
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class NavigationFilterPrefixWithBackspace extends NavigationFilter
{
private int prefixLength;
private Action deletePrevious;
public NavigationFilterPrefixWithBackspace(int prefixLength, JTextComponent component)
{
this.prefixLength = prefixLength;
deletePrevious = component.getActionMap().get("delete-previous");
component.getActionMap().put("delete-previous", new BackspaceAction());
}
public void setDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
{
fb.setDot(Math.max(dot, prefixLength), bias);
}
public void xxxmoveDot(NavigationFilter.FilterBypass fb, int dot, Position.Bias bias)
{
fb.moveDot(Math.max(dot, prefixLength), bias);
}
class BackspaceAction extends AbstractAction
{
public void actionPerformed(ActionEvent e)
{
JTextComponent component = (JTextComponent)e.getSource();
if (component.getCaretPosition() > prefixLength)
{
deletePrevious.actionPerformed( null );
}
}
}
public static void main(String args[]) throws Exception {
JTextField textField = new JTextField("Prefix_", 20);
textField.setCaretPosition(7);
textField.setNavigationFilter( new NavigationFilterPrefixWithBackspace(7, textField) );
JFrame frame = new JFrame("Navigation Filter Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(textField);
frame.pack();
frame.setLocationRelativeTo( null );
frame.setVisible(true);
}
}
> Actually a DocumentFilter won't work either, since no characters are being added to the Document
Actually DocumentFilter will work, you just have to override all 3 functions of [url http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/text/DocumentFilter.html]DocumentFilter[/url]
> Actually DocumentFilter will work, you just have to override all 3 functions of DocumentFilter
Thanks, I should have read the API more closely. The example from the tutorial only overrode two of the methods.
So I would say the best solution is probably a combination of the DocumentFilter to prevent the removal of the text and then maybe a NavigationFilter if you want to control the movement of the caret.