textcomponentdemo.java

java tutorial.sun公司官方出品。java入门书籍。最新版

/*
 * Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Sun Microsystems nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

package components;
/*
 * TextComponentDemo.java requires one additional file:
 *   DocumentSizeFilter.java
 */

import java.awt.*;
import java.awt.event.*;
import java.util.HashMap;

import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import javax.swing.undo.*;

public class TextComponentDemo extends JFrame {
    JTextPane textPane;
    AbstractDocument doc;
    static final int MAX_CHARACTERS = 300;
    JTextArea changeLog;
    String newline = "\n";
    HashMap<Object, Action> actions;

    //undo helpers
    protected UndoAction undoAction;
    protected RedoAction redoAction;
    protected UndoManager undo = new UndoManager();

    public TextComponentDemo() {
        super("TextComponentDemo");

        //Create the text pane and configure it.
        textPane = new JTextPane();
        textPane.setCaretPosition(0);
        textPane.setMargin(new Insets(5,5,5,5));
        StyledDocument styledDoc = textPane.getStyledDocument();
        if (styledDoc instanceof AbstractDocument) {
            doc = (AbstractDocument)styledDoc;
            doc.setDocumentFilter(new DocumentSizeFilter(MAX_CHARACTERS));
        } else {
            System.err.println("Text pane's document isn't an AbstractDocument!");
            System.exit(-1);
        }
        JScrollPane scrollPane = new JScrollPane(textPane);
        scrollPane.setPreferredSize(new Dimension(200, 200));

        //Create the text area for the status log and configure it.
        changeLog = new JTextArea(5, 30);
        changeLog.setEditable(false);
        JScrollPane scrollPaneForLog = new JScrollPane(changeLog);

        //Create a split pane for the change log and the text area.
        JSplitPane splitPane = new JSplitPane(
                                       JSplitPane.VERTICAL_SPLIT,
                                       scrollPane, scrollPaneForLog);
        splitPane.setOneTouchExpandable(true);

        //Create the status area.
        JPanel statusPane = new JPanel(new GridLayout(1, 1));
        CaretListenerLabel caretListenerLabel =
                new CaretListenerLabel("Caret Status");
        statusPane.add(caretListenerLabel);

        //Add the components.
        getContentPane().add(splitPane, BorderLayout.CENTER);
        getContentPane().add(statusPane, BorderLayout.PAGE_END);

        //Set up the menu bar.
        actions=createActionTable(textPane);
        JMenu editMenu = createEditMenu();
        JMenu styleMenu = createStyleMenu();
        JMenuBar mb = new JMenuBar();
        mb.add(editMenu);
        mb.add(styleMenu);
        setJMenuBar(mb);

        //Add some key bindings.
        addBindings();

        //Put the initial text into the text pane.
        initDocument();
        textPane.setCaretPosition(0);

        //Start watching for undoable edits and caret changes.
        doc.addUndoableEditListener(new MyUndoableEditListener());
        textPane.addCaretListener(caretListenerLabel);
        doc.addDocumentListener(new MyDocumentListener());
    }

    //This listens for and reports caret movements.
    protected class CaretListenerLabel extends JLabel
                                       implements CaretListener {
        public CaretListenerLabel(String label) {
            super(label);
        }

        //Might not be invoked from the event dispatch thread.
        public void caretUpdate(CaretEvent e) {
            displaySelectionInfo(e.getDot(), e.getMark());
        }

        //This method can be invoked from any thread.  It 
        //invokes the setText and modelToView methods, which 
        //must run on the event dispatch thread. We use
        //invokeLater to schedule the code for execution
        //on the event dispatch thread.
        protected void displaySelectionInfo(final int dot,
                                            final int mark) {
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    if (dot == mark) {  // no selection
                        try {
                            Rectangle caretCoords = textPane.modelToView(dot);
                            //Convert it to view coordinates.
                            setText("caret: text position: " + dot
                                    + ", view location = ["
                                    + caretCoords.x + ", "
                                    + caretCoords.y + "]"
                                    + newline);
                        } catch (BadLocationException ble) {
                            setText("caret: text position: " + dot + newline);
                        }
                    } else if (dot < mark) {
                        setText("selection from: " + dot
                                + " to " + mark + newline);
                    } else {
                        setText("selection from: " + mark
                                + " to " + dot + newline);
                    }
                }
            });
        }
    }

    //This one listens for edits that can be undone.
    protected class MyUndoableEditListener
                    implements UndoableEditListener {
        public void undoableEditHappened(UndoableEditEvent e) {
            //Remember the edit and update the menus.
            undo.addEdit(e.getEdit());
            undoAction.updateUndoState();
            redoAction.updateRedoState();
        }
    }

    //And this one listens for any changes to the document.
    protected class MyDocumentListener
                    implements DocumentListener {
        public void insertUpdate(DocumentEvent e) {
            displayEditInfo(e);
        }
        public void removeUpdate(DocumentEvent e) {
            displayEditInfo(e);
        }
        public void changedUpdate(DocumentEvent e) {
            displayEditInfo(e);
        }
        private void displayEditInfo(DocumentEvent e) {
            Document document = e.getDocument();
            int changeLength = e.getLength();
            changeLog.append(e.getType().toString() + ": " +
                changeLength + " character" +
                ((changeLength == 1) ? ". " : "s. ") +
                " Text length = " + document.getLength() +
                "." + newline);
        }
    }

    //Add a couple of emacs key bindings for navigation.
    protected void addBindings() {
        InputMap inputMap = textPane.getInputMap();

        //Ctrl-b to go backward one character
        KeyStroke key = KeyStroke.getKeyStroke(KeyEvent.VK_B, Event.CTRL_MASK);
        inputMap.put(key, DefaultEditorKit.backwardAction);

        //Ctrl-f to go forward one character
        key = KeyStroke.getKeyStroke(KeyEvent.VK_F, Event.CTRL_MASK);
        inputMap.put(key, DefaultEditorKit.forwardAction);

        //Ctrl-p to go up one line
        key = KeyStroke.getKeyStroke(KeyEvent.VK_P, Event.CTRL_MASK);
        inputMap.put(key, DefaultEditorKit.upAction);

        //Ctrl-n to go down one line
        key = KeyStroke.getKeyStroke(KeyEvent.VK_N, Event.CTRL_MASK);
        inputMap.put(key, DefaultEditorKit.downAction);
    }