textareaundodemopanel.java

Java与模式 源代码

package com.javapatterns.command.swingundo2;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

/* 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 = null;
        JButton buttonRedo = null;
        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");
    }
}