textareaundodemopanel.java

java与模式 一书的源码

package com.javapatterns.command.swingundo2;

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

/* App panel class
 */
class TextAreaUndoDemoPanel extends JPanel { 
    // Constructor
    public TextAreaUndoDemoPanel() { 
        setLayout(new BorderLayout());

        // create an undoable text area
        // must be final to be accessed by 
        // anonymous inner classes (listeners)
        final UndoableTextArea text 
                  = new UndoableTextArea("Your text here.");

        // create a toolbar for buttons
        JToolBar toolbar = new JToolBar();

        // create undo and redo buttons
        // add listeners for buttons
        JButton buttonUndo, buttonRedo;
        buttonUndo = new JButton("Undo");
        buttonUndo.addActionListener (new ActionListener () { 
            public void actionPerformed (ActionEvent event) { 
                text.undo ();
            } 
        } );
        buttonRedo = new JButton("Redo");
        buttonRedo.addActionListener (new ActionListener () { 
            public void actionPerformed (ActionEvent event) { 
                text.redo ();
            } 
        } );

        // add buttons to toolbar
        toolbar.add(buttonUndo);
        toolbar.add(buttonRedo);

        // add toolbar and text area to panel
        add(toolbar, "North");
        add(text, "Center");
    } 
}