All geek questions in one place

How to properly initialize a JTextPane StyleSheet so that no other component included in the HTML affects the style?

I am trying to use JTextPanesome CSS stylesheet to display some HTML code. This means that I use the HTMLEditorKitand classes StyleSheet. I know that everyone HTMLEditorKitsuses the same standard instance StyleSheet, so if you change this default style sheet object, you apply the changes at the application level (all components that display HTML).

But in my example, I thought I avoided this by creating my own instance StyleSheetbased on the default. However, this does not work, as seen on the display JTree, which displays according to the style sheet, which is intended only for applying to JTextPane.

import java.awt.*;
import javax.swing.*;
import javax.swing.text.html.*;
import javax.swing.tree.*;

public class TextPaneCssSpill extends JFrame {

    private JTextPane textPane;
    private JTree tree;
    private JSplitPane splitPane;

    public TextPaneCssSpill() {
        HTMLEditorKit hed = new HTMLEditorKit();
        StyleSheet defaultStyle = hed.getStyleSheet();
        StyleSheet style = new StyleSheet();
        style.addStyleSheet(defaultStyle);
        style.addRule("body {font-family:\"Monospaced\"; font-size:9px;}");
        style.addRule("i {color:#bababa; font-size:9px;}"); // gray italic
        hed.setStyleSheet(style);

        textPane = new JTextPane();        
        textPane.setEditorKit(hed);
        textPane.setDocument(hed.createDefaultDocument());

        DefaultMutableTreeNode root = new DefaultMutableTreeNode(new MyNode("name", "argument"), true);
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));

        tree = new JTree(root);
        tree.setCellRenderer(new MyNodeTreeRenderer());

        setLayout(new BorderLayout());
        splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, textPane, tree);
        add(splitPane);

        pack();
        setLocationRelativeTo(null);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TextPaneCssSpill().setVisible(true);
            }
        });
    }

    private static class MyNode {
        private final String name;
        private final String argument;

        public MyNode(String name, String argument) {
            this.name = name;
            this.argument = argument;
        }

        @Override
        public String toString() {
            return name + " " + argument;
        }        
    }

    private static class MyNodeTreeRenderer extends DefaultTreeCellRenderer {

        @Override
        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
            super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
            if (value instanceof DefaultMutableTreeNode) {
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
                if (node.getUserObject() instanceof MyNode) {
                    MyNode mynode = (MyNode) node.getUserObject();
                    setText("<html>" + mynode.name + "&nbsp;<i>" + mynode.argument);
                }
            }
            return this;
        }

    }
}

rendered example

So, how to properly initialize these objects so that there is no CSS spilling in the application (so that the text panel is displayed in accordance with CSS, but the tree does not work)?

Note: a red underline in the above image indicates a spill problem and was later added by me (no, this is not a visualization tool).

+4
source share
1 answer

HTMLEditorKit.setStyleSheet(style);. HTMLEditorKits, .

    /**
     * Set the set of styles to be used to render the various
     * HTML elements.  These styles are specified in terms of
     * CSS specifications.  Each document produced by the kit
     * will have a copy of the sheet which it can add the
     * document specific styles to.  By default, the StyleSheet
     * specified is shared by all HTMLEditorKit instances.
     * This should be reimplemented to provide a finer granularity
     * if desired.
     */
    public void setStyleSheet(StyleSheet s) {
        if (s == null) {
            AppContext.getAppContext().remove(DEFAULT_STYLES_KEY);
        } else {
            AppContext.getAppContext().put(DEFAULT_STYLES_KEY, s);
        }
    }

    /**
     * Get the set of styles currently being used to render the
     * HTML elements.  By default the resource specified by
     * DEFAULT_CSS gets loaded, and is shared by all HTMLEditorKit
     * instances.
     */
    public StyleSheet getStyleSheet() {
        AppContext appContext = AppContext.getAppContext();
        StyleSheet defaultStyles = (StyleSheet) appContext.get(DEFAULT_STYLES_KEY);

        if (defaultStyles == null) {
            defaultStyles = new StyleSheet();
            appContext.put(DEFAULT_STYLES_KEY, defaultStyles);
            try {
                InputStream is = HTMLEditorKit.getResourceAsStream(DEFAULT_CSS);
                Reader r = new BufferedReader(
                        new InputStreamReader(is, "ISO-8859-1"));
                defaultStyles.loadRules(r, null);
                r.close();
            } catch (Throwable e) {
                // on error we simply have no styles... the html
                // will look mighty wrong but still function.
            }
        }
        return defaultStyles;
    }

, , HTMLEditorKit, .

import java.awt.*;
import java.io.IOException;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.text.html.*;
import javax.swing.tree.*;

public class TextPaneCssSpill extends JFrame {

    private JTextPane textPane;
    private JTree tree;
    private JSplitPane splitPane;
    private StyleSheet style;

    public TextPaneCssSpill() {
        MyHTMLEditorKit hed = new MyHTMLEditorKit();
        StyleSheet defaultStyle = hed.getDefaultStyleSheet();
        style = new StyleSheet();
        style.addStyleSheet(defaultStyle);
        style.addRule("body {font-family:\"Monospaced\"; font-size:9px;}");
        style.addRule("i {color:#bababa; font-size:9px;}"); // gray italic
        hed.setStyleSheet(style);

        textPane = new JTextPane();        
        textPane.setEditorKit(hed);
        textPane.setDocument(hed.createDefaultDocument());
        appendHtmlToTextPane("<i>our gray italic text</i>", textPane);

        DefaultMutableTreeNode root = new DefaultMutableTreeNode(new MyNode("name", "argument"), true);
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));
        root.add(new DefaultMutableTreeNode(new MyNode("name", "argument"), false));

        tree = new JTree(root);
        tree.setCellRenderer(new MyNodeTreeRenderer());

        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLayout(new BorderLayout());
        splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, textPane, tree);
        add(splitPane);

        pack();
        setLocationRelativeTo(null);
    }

    private void appendHtmlToTextPane(String str, JTextPane pane) {
        Document doc = pane.getDocument();
        if (doc != null) {
            if (doc instanceof HTMLDocument) {
                HTMLDocument htmlDoc = (HTMLDocument) doc;
                Element html = htmlDoc.getDefaultRootElement();
                if (HTML.Tag.HTML.toString().equalsIgnoreCase(html.getName())) {
                    Element body = null;
                    for (int i = 0; i < html.getElementCount(); i++) {
                        Element element = html.getElement(i);
                        if (element.getAttributes().getAttribute(StyleConstants.NameAttribute) == HTML.Tag.BODY) {
                            body = element;
                            break;
                        }
                    }
                    if (HTML.Tag.BODY.toString().equalsIgnoreCase(body.getName())) {
                        try {                            
                            htmlDoc.insertBeforeEnd(body, str);
                            Element lastLine = body.getElement(body.getElementCount() - 1);
                            int end = lastLine.getStartOffset();
                            textPane.setCaretPosition(end);

                        } catch (BadLocationException e) {
                        } catch (IOException ex) {
                        }
                    }
                }
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TextPaneCssSpill().setVisible(true);
            }
        });
    }

    private static class MyNode {
        private final String name;
        private final String argument;

        public MyNode(String name, String argument) {
            this.name = name;
            this.argument = argument;
        }

        @Override
        public String toString() {
            return name + " " + argument;
        }        
    }

    private static class MyNodeTreeRenderer extends DefaultTreeCellRenderer {

        @Override
        public Component getTreeCellRendererComponent(JTree tree, Object value, boolean sel, boolean expanded, boolean leaf, int row, boolean hasFocus) {
            super.getTreeCellRendererComponent(tree, value, sel, expanded, leaf, row, hasFocus);
            if (value instanceof DefaultMutableTreeNode) {
                DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
                if (node.getUserObject() instanceof MyNode) {
                    MyNode mynode = (MyNode) node.getUserObject();
                    setText("<html>" + mynode.name + "&nbsp;<i>" + mynode.argument);
                }
            }
            return this;
        }

    }

    /**
     * Avoid setting the stylesheet for all HTMLEditorKit instances.
     */
    private static class MyHTMLEditorKit extends HTMLEditorKit {

        private StyleSheet myStyle;

        @Override
        public StyleSheet getStyleSheet() {
            return myStyle == null ? super.getStyleSheet() : myStyle;
        }

        @Override
        public void setStyleSheet(StyleSheet s) {
            this.myStyle = s;
        }

        public StyleSheet getDefaultStyleSheet() {
            return super.getStyleSheet();
        }

        public void setDefaultStyleSheet(StyleSheet s) {
            super.setStyleSheet(s);
        }

    }
}

fixed version

+4

Source: https://habr.com/ru/post/1674816/

More articles:


All Articles