UndoUtil.java

Vá para a documentação deste arquivo.

package plp;

import java.awt.event.ActionEvent;

import javax.swing.AbstractAction;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;
import javax.swing.event.UndoableEditEvent;
import javax.swing.event.UndoableEditListener;
import javax.swing.text.Document;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;

public class UndoUtil {

        public static void registerUndoManager(JTextArea textArea) {
                final UndoManager undo = new UndoManager();
                Document doc = textArea.getDocument();

                // Listen for undo and redo events
                doc.addUndoableEditListener(new UndoableEditListener() {
                        public void undoableEditHappened(UndoableEditEvent evt) {
                                undo.addEdit(evt.getEdit());
                        }
                });

                // Create an undo action and add it to the text component
                textArea.getActionMap().put("Undo", new AbstractAction("Undo") {
                        private static final long serialVersionUID = 1L;

                        public void actionPerformed(ActionEvent evt) {
                                try {
                                        if (undo.canUndo()) {
                                                undo.undo();
                                        }
                                } catch (CannotUndoException e) {
                                }
                        }
                });

                // Bind the undo action to ctl-Z
                textArea.getInputMap().put(KeyStroke.getKeyStroke("control Z"), "Undo");

                // Create a redo action and add it to the text component
                textArea.getActionMap().put("Redo", new AbstractAction("Redo") {
                        private static final long serialVersionUID = 1L;

                        public void actionPerformed(ActionEvent evt) {
                                try {
                                        if (undo.canRedo()) {
                                                undo.redo();
                                        }
                                } catch (CannotRedoException e) {
                                }
                        }
                });

                // Bind the redo action to ctl-Y
                textArea.getInputMap().put(KeyStroke.getKeyStroke("control Y"), "Redo");
        }

}

---