Undo Drawing : Undo Redo « Swing JFC « Java

Undo Drawing

Undo Drawing
Definitive Guide to Swing for Java 2, Second Edition
By John Zukowski     
ISBN: 1-893115-78-X
Publisher: APress

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Polygon;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.event.UndoableEditListener;
import javax.swing.undo.AbstractUndoableEdit;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.CannotUndoException;
import javax.swing.undo.UndoManager;
import javax.swing.undo.UndoableEditSupport;

public class UndoDrawing {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Drawing Sample");
    UndoableDrawingPanel drawingPanel = new UndoableDrawingPanel();

    UndoManager manager = new UndoManager();

    JToolBar toolbar = new JToolBar();

    Container content = frame.getContentPane();
    content.add(toolbar, BorderLayout.NORTH);
    content.add(drawingPanel, BorderLayout.CENTER);
    frame.setSize(300, 150);

class UndoableDrawingPanel extends JPanel {
  UndoableEditSupport undoableEditSupport = new UndoableEditSupport(this);

  Polygon polygon = new Polygon();

  public UndoableDrawingPanel() {
    MouseListener mouseListener = new MouseAdapter() {
      public void mouseReleased(MouseEvent mouseEvent) {
        undoableEditSupport.postEdit(new UndoableDrawEdit(
        polygon.addPoint(mouseEvent.getX(), mouseEvent.getY());

  public void addUndoableEditListener(
      UndoableEditListener undoableEditListener) {

  public void removeUndoableEditListener(
      UndoableEditListener undoableEditListener) {

  public void setPolygon(Polygon newValue) {
    polygon = newValue;

  public Polygon getPolygon() {
    Polygon returnValue;
    if (polygon.npoints == 0) {
      returnValue = new Polygon();
    } else {
      returnValue = new Polygon(polygon.xpoints, polygon.ypoints,
    return returnValue;

  protected void paintComponent(Graphics g) {

class UndoManagerHelper {

  public static Action getUndoAction(UndoManager manager, String label) {
    return new UndoAction(manager, label);

  public static Action getUndoAction(UndoManager manager) {
    return new UndoAction(manager, "Undo");

  public static Action getRedoAction(UndoManager manager, String label) {
    return new RedoAction(manager, label);

  public static Action getRedoAction(UndoManager manager) {
    return new RedoAction(manager, "Redo");

  private abstract static class UndoRedoAction extends AbstractAction {
    UndoManager undoManager = new UndoManager();

    String errorMessage = "Cannot undo";

    String errorTitle = "Undo Problem";

    protected UndoRedoAction(UndoManager manager, String name) {
      undoManager = manager;

    public void setErrorMessage(String newValue) {
      errorMessage = newValue;

    public void setErrorTitle(String newValue) {
      errorTitle = newValue;

    protected void showMessage(Object source) {
      if (source instanceof Component) {
        JOptionPane.showMessageDialog((Component) source, errorMessage,
            errorTitle, JOptionPane.WARNING_MESSAGE);
      } else {

  public static class UndoAction extends UndoRedoAction {
    public UndoAction(UndoManager manager, String name) {
      super(manager, name);
      setErrorMessage("Cannot undo");
      setErrorTitle("Undo Problem");

    public void actionPerformed(ActionEvent actionEvent) {
      try {
      } catch (CannotUndoException cannotUndoException) {

  public static class RedoAction extends UndoRedoAction {
    String errorMessage = "Cannot redo";

    String errorTitle = "Redo Problem";

    public RedoAction(UndoManager manager, String name) {
      super(manager, name);
      setErrorMessage("Cannot redo");
      setErrorTitle("Redo Problem");

    public void actionPerformed(ActionEvent actionEvent) {
      try {
      } catch (CannotRedoException cannotRedoException) {


class UndoableDrawEdit extends AbstractUndoableEdit {
  UndoableDrawingPanel panel;

  Polygon polygon, savedPolygon;

  public UndoableDrawEdit(UndoableDrawingPanel panel) {
    this.panel = panel;
    polygon = panel.getPolygon();

  public String getPresentationName() {
    return "Polygon of size " + polygon.npoints;

  public void redo() throws CannotRedoException {
    if (savedPolygon == null) {
      // Should never get here, as super() doesn't permit redoing
      throw new CannotRedoException();
    } else {
      savedPolygon = null;

  public void undo() throws CannotUndoException {
    savedPolygon = panel.getPolygon();


Related examples in the same category

1.The use of UndoableToggleEditThe use of UndoableToggleEdit
2.The use of StateEdit(able)The use of StateEdit(able)
3.The use of UndoManagerThe use of UndoManager
4.A sample app showing the use of UndoableToggleEdit and CompoundEditA sample app showing the use of UndoableToggleEdit and CompoundEdit
5.An example that shows lots of little UndoManager detailsAn example that shows lots of little UndoManager details
6.Undo redo textareaUndo redo textarea
7.Undo managerUndo manager
8.Simple GUI demo of UndoManager and friendsSimple GUI demo of UndoManager and friends
9.Undo Example 1Undo Example 1
10.Undo Example 2Undo Example 2
11.Undo Example 3Undo Example 3
12.Undo Example 4Undo Example 4
13.Undo Example 5Undo Example 5
14.Undo Example 6Undo Example 6
15.Undoable Drawing Panel 2Undoable Drawing Panel 2
16.Undo Example 7Undo Example 7
17.Creating TextArea with Undo, Redo Capabilities
18.Add Undo and Redo to a text component
19.Add undo support to the StyleFrame exampleAdd undo support to the StyleFrame example
20.Adding Undo and Redo to a Text Component
21.Create a redo action and add it to the text component (JTextComponent)
22.Listen for undo and redo events
23.Create an undo action and add it to the text component
24.Bind the undo action to ctl-Z