Problem in Undo/Redo operation in JTextField

Ravi Prakash H Fri, 02 Apr 2004 07:38:22 -0800

Hi all,

I have to do undo/redo operation in JTextField. I was able to do with UndoManager, but the problem when using UndoManager is when we enter some text it undoes by each character rather the whole world entered by us. I have used CompoundEdit for this purporse and attached a undoableEditListener to the document of JTextField. but this does't work as expected giving eratic behaviour(unconsistent undo operations). Please suggest me a better alternative or correction for doing undo/redo operation in JTextField which undo whatever the user entered in a single go like in NotePad editor.

I am attaching my code for the reference Please let me know where i am missing something

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.undo.*;
import javax.swing.event.*;

public class UndoRedoTextApp extends JFrame
{
protected JTextArea m_editor = new JTextArea();
protected UndoManager undoManager = new UndoManager();
protected CompoundEdit compoundEdit; // = new CompoundEdit();
protected JButton m_undoButton = new JButton("Undo");
protected JButton m_redoButton = new JButton("Redo");

public UndoRedoTextApp() {
super("Undo/Redo Demo");

    JPanel buttonPanel = new JPanel(new GridLayout());
    buttonPanel.add(m_undoButton);
    buttonPanel.add(m_redoButton);

JScrollPane scroller = new JScrollPane(m_editor);

getContentPane().add(buttonPanel, BorderLayout.NORTH);
getContentPane().add(scroller, BorderLayout.CENTER);

    m_editor.getDocument().addUndoableEditListener(new UndoableEditListener() {
      public void undoableEditHappened(UndoableEditEvent e) {
          if( compoundEdit == null || compoundEdit.isInProgress() == false)
          {
              compoundEdit = new CompoundEdit();
              System.out.println("new edit is created");
          }
            boolean added = compoundEdit.addEdit(e.getEdit());
            updateButtons("undoableedit");
      }
    });

    m_undoButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
                   compoundEdit.end();
                    undoManager.addEdit(compoundEdit);
                    undoManager.undo();
                       }
        catch (CannotUndoException cre) { cre.printStackTrace(); }
        updateButtons("4");
      }
    });

    m_redoButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
                undoManager.redo();
        }
        catch (CannotRedoException cre) { cre.printStackTrace(); }
        updateButtons("5");
      }
    });

setSize(400,300);
setVisible(true);
}

public void updateButtons(String str) {
    System.out.println("updatebutton" + str);
    m_undoButton.setText(compoundEdit.getUndoPresentationName());
    m_redoButton.setText(compoundEdit.getRedoPresentationName());
}

public static void main(String argv[]) {
new UndoRedoTextApp();

}

}

Thanks in advance

Problem in Undo/Redo operation in JTextField

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