Undo manager : Undo Redo « Swing JFC « Java

1. Java
2. Swing JFC
3. Undo Redo

Undo manager

 

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.Enumeration;
import java.util.Vector;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.event.UndoableEditEvent;
import javax.swing.undo.AbstractUndoableEdit;
import javax.swing.undo.CannotRedoException;
import javax.swing.undo.UndoManager;

public class UndoManagerDemo extends JFrame {
  protected Vector pointVector = new Vector();

  protected PaintCanvas canvas = new PaintCanvas(pointVector);

  protected UndoManager undoManager = new UndoManager();

  protected JButton undoButton = new JButton("Undo");

  protected JButton redoButton = new JButton("Redo");

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

    undoButton.setEnabled(false);
    redoButton.setEnabled(false);

    JPanel buttonPanel = new JPanel(new GridLayout());
    buttonPanel.add(undoButton);
    buttonPanel.add(redoButton);

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

    canvas.addMouseListener(new MouseAdapter() {
      public void mousePressed(MouseEvent e) {
        Point point = new Point(e.getX(), e.getY());
        pointVector.addElement(point);

        undoManager.undoableEditHappened(new UndoableEditEvent(
            canvas, new UndoablePaintSquare(point, pointVector)));

        undoButton.setText(undoManager.getUndoPresentationName());
        redoButton.setText(undoManager.getRedoPresentationName());
        undoButton.setEnabled(undoManager.canUndo());
        redoButton.setEnabled(undoManager.canRedo());
        canvas.repaint();
      }
    });

    undoButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          undoManager.undo();
        } catch (CannotRedoException cre) {
          cre.printStackTrace();
        }
        canvas.repaint();
        undoButton.setEnabled(undoManager.canUndo());
        redoButton.setEnabled(undoManager.canRedo());
      }
    });

    redoButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        try {
          undoManager.redo();
        } catch (CannotRedoException cre) {
          cre.printStackTrace();
        }
        canvas.repaint();
        undoButton.setEnabled(undoManager.canUndo());
        redoButton.setEnabled(undoManager.canRedo());
      }
    });

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

  public static void main(String argv[]) {
    new UndoManagerDemo();
  }
  class PaintCanvas extends JPanel {
    private Vector points;

    protected int width = 50;

    protected int height = 50;

    public PaintCanvas(Vector v) {
      super();
      points = v;
      setOpaque(true);
      setBackground(Color.white);
    }

    public void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.setColor(Color.black);
      
      for(int i=0;i<points.size();i++){
        Point point = (Point) points.get(i);
        g.drawRect(point.x, point.y, width, height);
      }
    }
  }

  class UndoablePaintSquare extends AbstractUndoableEdit {
    protected Vector points;

    protected Point point;

    public UndoablePaintSquare(Point p, Vector v) {
      points = v;
      point = p;
    }

    public String getPresentationName() {
      return "Square Addition";
    }

    public void undo() {
      super.undo();
      points.remove(point);
    }

    public void redo() {
      super.redo();
      points.add(point);
    }
  }
}

           
         
  

Related examples in the same category

1.	The use of UndoableToggleEdit
2.	The use of StateEdit(able)
3.	The use of UndoManager
4.	A sample app showing the use of UndoableToggleEdit and CompoundEdit
5.	An example that shows lots of little UndoManager details
6.	Undo redo textarea
7.	Simple GUI demo of UndoManager and friends
8.	Undo Example 1
9.	Undo Example 2
10.	Undo Example 3
11.	Undo Example 4
12.	Undo Example 5
13.	Undo Example 6
14.	Undoable Drawing Panel 2
15.	Undo Drawing
16.	Undo 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 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