如何清除JTextPane中的所有样式？

Question

I am creating a simple .rtf file editor application using RTFEditorKit() . I have added code to create a new document, open an .rtf document, save as an .rtf document, and to add styles to the content of the document such as bold, italics and underline.

I am using a JTextPane .

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Here is my problem: I have added some styles to the content (eg bold, italics, underline or color) to the text. Then, saving or without saving that document I am opening a new document by clicking on the "New Document" icon.

If I enter some text in the New document, the text is displaying with the bold, italics, underline and color styles that I used in the previous document; whereas I would have expected these to have been cleared.

How can I achieve this? I have tried three different ways in "New Document" action listener - none of them work. These can be seen below:

StyledDocument styledDocument = new DefaultStyledDocument();
textPane.setStyledDocument(styledDocument = new DefaultStyledDocument());

---

Style bold = textPane.addStyle("bold", null);
textPane.getStyledDocument().setCharacterAttributes(0, textPane.getStyledDocument().getLength(), bold, false);

---

textPane.setFont(new Font("Arial", Font.PLAIN, 15));
textPane.setText("");

My application minimal code:

public class MyNotepadMini implements ActionListener {
public static JFrame frame;
public static JPanel panel;
public static JTextPane textPane;
public static RTFEditorKit rtf;
public static StyleContext styleContext;
public static DefaultStyledDocument defaultStyleDoc;
public static JScrollPane scrollPane;
public static JMenuBar menuBar;
public static JMenu fileMenu;
public static JMenu editMenu;
public static JMenu formatMenu;
public static JMenuItem newSubMenu;
public static JMenuItem openSubMenu;
public static JMenuItem save;
public static JMenuItem saveAs;
public static JMenuItem cut;
public static JMenuItem copy;
public static JMenuItem paste;
public static JMenuItem selectAll;
public static JMenuItem bold;
public static JMenuItem italic;
public static JMenuItem underline;
public static JMenuItem exit;
public static JFileChooser fc;
public static boolean openFileExtFlag = true;
public static boolean saveFileExtFlag = true;
public static File openFile;
public static File saveFile;
public static boolean saveWindowTitle = false;
public static boolean openFileFlag;
public static boolean saveFileFlag;
public static boolean saved = true;
public static boolean dontSaveOption;
public static BufferedReader br;
public static boolean saveForNewOpenExitListener;
public static boolean saveAsFlag;
public static int returnVal;
public static String filePath;
public static boolean flagForOpenListener;
public static StyledDocument styledDocument;
public static Style defaultStyle;

public MyNotepadMini() {
    try {
        UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
    } catch (Exception e) {
        e.printStackTrace();
    }
    frame = new JFrame("My Notepad");
    panel = new JPanel(new BorderLayout());      

    styledDocument = new DefaultStyledDocument();
    rtf = new RTFEditorKit();
    textPane = new JTextPane(styledDocument);
    textPane.setEditorKit(rtf);
    styleContext = new StyleContext();

    scrollPane = new JScrollPane();
    scrollPane.getViewport().add(textPane);
    menuBar = new JMenuBar();
    fileMenu = new JMenu("File");
    fileMenu.setMnemonic(KeyEvent.VK_F);
    newSubMenu = new JMenuItem("New");
    newSubMenu.setAccelerator(KeyStroke.getKeyStroke('N', CTRL_DOWN_MASK));
    openSubMenu = new JMenuItem("Open...");
    openSubMenu.setAccelerator(KeyStroke.getKeyStroke('O', CTRL_DOWN_MASK));
    save = new JMenuItem("Save");
    save.setAccelerator(KeyStroke.getKeyStroke('S', CTRL_DOWN_MASK));
    editMenu = new JMenu("Edit");
    editMenu.setMnemonic(KeyEvent.VK_E);
    cut = new JMenuItem("Cut");
    cut.setAccelerator(KeyStroke.getKeyStroke('X', CTRL_DOWN_MASK));
    copy = new JMenuItem("Copy");
    copy.setAccelerator(KeyStroke.getKeyStroke('C', CTRL_DOWN_MASK));
    paste = new JMenuItem("Paste");
    paste.setAccelerator(KeyStroke.getKeyStroke('V', CTRL_DOWN_MASK));
    selectAll = new JMenuItem("Select All");
    selectAll.setAccelerator(KeyStroke.getKeyStroke('A', CTRL_DOWN_MASK));
    exit = new JMenuItem("Exit");
    exit.setMnemonic(KeyEvent.VK_X);
    formatMenu = new JMenu("Format");
    formatMenu.setMnemonic(KeyEvent.VK_F);
    bold = new JMenuItem(new StyledEditorKit.BoldAction());
    bold.setText("Bold");
    bold.setMnemonic(KeyEvent.VK_B);
    bold.setAccelerator(KeyStroke.getKeyStroke('B', CTRL_DOWN_MASK));
    italic = new JMenuItem(new StyledEditorKit.ItalicAction());
    italic.setText("Italic");
    italic.setMnemonic(KeyEvent.VK_I);
    italic.setAccelerator(KeyStroke.getKeyStroke('I', CTRL_DOWN_MASK));
    underline = new JMenuItem(new StyledEditorKit.UnderlineAction());
    underline.setText("Underline");
    underline.setMnemonic(KeyEvent.VK_U);
    underline.setAccelerator(KeyStroke.getKeyStroke('U', CTRL_DOWN_MASK));

    defaultStyle = StyleContext.getDefaultStyleContext().getStyle(StyleContext.DEFAULT_STYLE);

    cut.addActionListener(this);
    copy.addActionListener(this);
    paste.addActionListener(this);
    selectAll.addActionListener(this);
    exit.addActionListener(this);
    newSubMenu.addActionListener(this);

    editMenu.addMenuListener(new MenuListener() {
        public void menuSelected(MenuEvent event) {
            if (textPane.getSelectionStart() == textPane.getSelectionEnd()) {
                cut.setEnabled(false);
                copy.setEnabled(false);
            } else {
                cut.setEnabled(true);
                copy.setEnabled(true);
            }
        }

        public void menuDeselected(MenuEvent event) {
        }

        public void menuCanceled(MenuEvent event) {  
        }
    });

    scrollPane.setPreferredSize(new Dimension(700,500));
    fileMenu.add(newSubMenu);
    fileMenu.add(openSubMenu);
    fileMenu.add(save);
    fileMenu.add(exit);
    editMenu.add(cut);
    editMenu.add(copy);
    editMenu.add(paste);
    editMenu.addSeparator();
    editMenu.add(selectAll);
    formatMenu.add(bold);
    formatMenu.add(italic);
    formatMenu.add(underline);
    menuBar.add(fileMenu);
    menuBar.add(editMenu);
    menuBar.add(formatMenu);

    textPane.setFont(new Font("Arial", Font.PLAIN, 12));    
    panel.add(scrollPane, BorderLayout.CENTER);
    panel.add(new JLabel(" "), BorderLayout.EAST);
    panel.add(new JLabel(" "), BorderLayout.WEST);
    panel.add(new JLabel(" "), BorderLayout.SOUTH);

    frame.setJMenuBar(menuBar);
    frame.add(panel);
    frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    frame.pack();
    textPane.requestFocus();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

public static void main(String[] args) {
    new MyNotepadMini();
}

public void actionPerformed(ActionEvent ae) {
    if ((ae.getSource() == cut)) {
        textPane.cut();
        textPane.requestFocus();
    } else if ((ae.getSource() == copy)) {
        textPane.copy();
        textPane.requestFocus();
    } else if ((ae.getSource() == paste)) {
        textPane.paste();
        textPane.requestFocus();
    } else if (ae.getSource() == selectAll) {
        textPane.selectAll();
    } else if ((ae.getSource() == exit)){   
        System.exit(0);
    } else if ((ae.getSource() == newSubMenu)) {                        /** New document **/
            textPane.setText("");
            textPane.setStyledDocument(styledDocument = new DefaultStyledDocument());

            Style bold = textPane.addStyle("bold", null);
            textPane.getStyledDocument().setCharacterAttributes(0, textPane.getStyledDocument().getLength(), bold, false);

            /*sampleDocument.setCharacterAttributes(0, sampleDocument.getLength(), defaultStyle, true);
              defaultStyleDoc = new DefaultStyledDocument(styleContext);
              textPane.setDocument(defaultStyleDoc);*/

            /*textPane.setFont(new Font("Arial", Font.PLAIN, 15));
            textPane.setText("");*/

            textPane.requestFocus();
        } 
}

}

Answer 1

I have given the minimal code here.

That is not the minimal code or a proper MCVE".

1. We should be able to copy/paste/compile/test. So you need to include the import statements

2. The cut/copy/paste Actions and menu items are not relevant to the problem so they should not be included.

We only have a certain amount of time to answer questions so we only want to look at minimal code that is directly related to the problem.

How to get rid of these styles in the New document - the text should be plain.

The problem is not the Document.

Every time the caret of the text pane is moved the text pane keeps track of the input attributes at the caret position. So when you create the new Document if the caret happens to be positioned on a character with the 3 attributes, those attributes are retained the next time you start typing.

You can clear these attributes by using:

MutableAttributeSet mas = textPane.getInputAttributes();
System.out.println("before: " + mas);
mas.removeAttributes(mas);
System.out.println("after: " + mas);

when you create your new Document.

Also,

public static JFrame frame;
public static JPanel panel;
public static JTextPane textPane;

You should not be using the static keyword an any of your variables.