打开文件时颜色更改不起作用

Question

我正在开发一个记事本程序，当用户键入时，如果键入某个单词（例如：public、void、private、protected、static），颜色会变为深红色（就像在 eclipse 中一样），但是如果用户打开一个文件，它不会改变颜色，即使用户键入，也不会发生任何事情。它仅在键入“新”文档时才有效。这是我的所有必要项目的简短版本：

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;

import javax.swing.*;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.SimpleAttributeSet;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;

public class Test {
    static JTabbedPane tabbedPane;
    static JTextPane txt;

    private static int findLastNonWordChar(String text, int index) {
        while (--index >= 0) {
            if (String.valueOf(text.charAt(index)).matches("\\W")) {
                break;
            }
        }
        return index;
    }

    private static int findFirstNonWordChar(String text, int index) {
        while (index < text.length()) {
            if (String.valueOf(text.charAt(index)).matches("\\W")) {
                break;
            }
            index++;
        }
        return index;
    }

    private static void makeBold(SimpleAttributeSet sas) {
        sas.addAttribute(StyleConstants.CharacterConstants.Bold, Boolean.TRUE);
    }

    private static void makeUnBold(SimpleAttributeSet sas) {
        sas.addAttribute(StyleConstants.CharacterConstants.Bold, Boolean.FALSE);
    }

    private static JTextPane createEmptyDocument() {
        final StyleContext cont = StyleContext.getDefaultStyleContext();
        final AttributeSet attrRed = cont.addAttribute(cont.getEmptySet(), StyleConstants.Foreground, new Color(127, 0, 85));
        final AttributeSet attrBlack = cont.addAttribute(cont.getEmptySet(), StyleConstants.Foreground, Color.BLACK);
        SimpleAttributeSet sas = new SimpleAttributeSet();

        DefaultStyledDocument document = new DefaultStyledDocument() {
            public void insertString(int offset, String str, AttributeSet a) throws BadLocationException {
                super.insertString(offset, str, a);

                String text = getText(0, getLength());
                int before = findLastNonWordChar(text, offset);
                if (before < 0) before = 0;
                int after = findFirstNonWordChar(text, offset + str.length());
                int wordL = before;
                int wordR = before;

                while (wordR <= after) {
                    if (wordR == after || String.valueOf(text.charAt(wordR)).matches("\\W")) {
                        if (text.substring(wordL, wordR).matches("(\\W)*(public|static|void|main|private|protected)")) {
                            setCharacterAttributes(wordL, wordR - wordL, attrRed, false);
                            makeBold(sas);
                            setCharacterAttributes(wordL, wordR - wordL, sas, false);
                        } else {
                            setCharacterAttributes(wordL, wordR - wordL, attrBlack, false);
                            makeUnBold(sas);
                            setCharacterAttributes(wordL, wordR - wordL, sas, false);
                        }
                        wordL = wordR;
                    }
                    wordR++;
                }
            }

            public void remove(int offs, int len) throws BadLocationException {
                super.remove(offs, len);

                String text = getText(0, getLength());
                int before = findLastNonWordChar(text, offs);
                if (before < 0) before = 0;
                int after = findFirstNonWordChar(text, offs);

                if (text.substring(before, after).matches("(\\W)*(public|static|void|private|protected)")) {
                    makeBold(sas);
                    setCharacterAttributes(before, after - before, attrRed, false);
                    setCharacterAttributes(before, after - before, sas, false);
                } else {
                    makeUnBold(sas);
                    setCharacterAttributes(before, after - before, attrBlack, false);
                    setCharacterAttributes(before, after - before, sas, false);
                }
            }
        };
        return new JTextPane(document);
    }

    private static void readInFile(File file, JTextPane txt) {
        try {
            FileReader r = new FileReader(file);
            txt.read(r, null);
            r.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void createNewDocument(File file, JTabbedPane tabbedPane) {
        txt = createEmptyDocument();

        String fileName;
        String theFile;

        if (file == null) {
            fileName = "Untitled";
            theFile = "Untitled";
        } else {
            fileName = file.getName().toString();
            theFile = file.toString();

            readInFile(file, txt);
        }

        txt.setFont(new Font("Monospaced", Font.PLAIN, 14));

        JScrollPane scrollPane = new JScrollPane(txt);

        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());
        panel.add(scrollPane);
        panel.setPreferredSize(new Dimension(800, 600));

        tabbedPane.addTab(fileName, null, panel, theFile);
        tabbedPane.setSelectedIndex(tabbedPane.getTabCount() - 1);

        tabbedPane.setFocusable(false);
        txt.grabFocus();
    }

    private static JTabbedPane setupForTabs(JFrame frame) {
        JPanel topPanel = new JPanel();
        topPanel.setLayout(new BorderLayout());

        tabbedPane = new JTabbedPane();

        topPanel.add(tabbedPane);
        frame.add(topPanel, BorderLayout.CENTER);

        return tabbedPane;
    }

    static Action New = new AbstractAction("New") {
        @Override
        public void actionPerformed(ActionEvent e) {
            createNewDocument(null, tabbedPane);
        }
    };

    static Action Open = new AbstractAction("Open") {
        @Override
        public void actionPerformed(ActionEvent e) {
            JFileChooser chooser = new JFileChooser();
            int result = chooser.showOpenDialog(tabbedPane);

            if (result == JFileChooser.APPROVE_OPTION) {
                File file = chooser.getSelectedFile();
                createNewDocument(file, tabbedPane);
            }
        }
    };

    private static JMenuBar createMenuBar(JTabbedPane tabbedPane) {
        JMenuBar menuBar = new JMenuBar();
        JMenu file = new JMenu("File");

        JMenuItem newDoc = new JMenuItem();
        JMenuItem open = new JMenuItem();

        New.putValue(Action.ACCELERATOR_KEY, KeyStroke.getKeyStroke(KeyEvent.VK_N, KeyEvent.CTRL_DOWN_MASK));
        newDoc.setAction(New);

        Open.putValue(Action.ACCELERATOR_KEY, KeyStroke.getKeyStroke(KeyEvent.VK_O, KeyEvent.CTRL_DOWN_MASK));
        open.setAction(Open);

        menuBar.add(file);

        file.add(newDoc);
        file.add(open);

        return menuBar;
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("Notepad");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(800, 600);

        tabbedPane = setupForTabs(frame);

        createNewDocument(null, tabbedPane);

        JMenuBar menuBar = createMenuBar(tabbedPane);
        frame.setJMenuBar(menuBar);

        frame.pack();

        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        frame.setLocation(dim.width/2-frame.getSize().width/2, dim.height/2-frame.getSize().height/2);

        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                UIManager.put("swing.boldmetal", Boolean.FALSE);
                createAndShowGui();
            }
        });
    }
}

即使在打开文件时，我也需要更改这些关键字的颜色。现在我没有在打开文件后搜索单词的方法，但我担心当用户在打开的文档中键入时颜色会发生变化。如果有人可以提示我如何在打开文件后搜索单词并更改颜色，那也很棒。 :)

Answer 1

read(...) 方法在读取文本文件时会创建一个新的PlainDocument。

不要创建匿名内部类，而是为您的 Document 创建一个自定义类，可能是“ColoredDocument”。

然后你可以使用如下代码：

EditorKit editorKit = new StyledEditorKit()
{
    public Document createDefaultDocument()
    {
        return new ColoredDocument();
    }
};

JTextPane textPane = new JTextPane();
textPane.setEditorKit( editorKit );

FileReader fr = new FileReader( ... );
BufferedReader br = new BufferedReader( fr );
textPane.read( br, null );