I currently use a JTextPane to allow users to add/edit text. It allows bold/italic/underline (and I plan to allow links in the future). It also allows users to drop buttons in, which are inserted as custom styles. The panel looks like:
< < image deleted > >
I would like to be able to save/load content as HTML - the content will be incorporated in a Flash swf. I am able to get content as HTML like so:
public String getHTMLText(){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try{
HTMLEditorKit hk = new HTMLEditorKit();
hk.write(baos, this.getStyledDocument(), 0, this.getDocument().getLength());
} catch (IOException e) {
e.printStackTrace();
} catch (BadLocationException e) {
e.printStackTrace();
}
return baos.toString();
}
This works fine if the JTextPane includes only bold/italic/underlined text. The output is overly complicated though. I want to be able to output my custom style as well, but when I try I'm getting this error:
Exception occurred during event dispatching:
java.lang.NullPointerException
at javax.swing.text.html.MinimalHTMLWriter.writeAttributes(MinimalHTMLWriter.java:151)
at javax.swing.text.html.MinimalHTMLWriter.writeStyles(MinimalHTMLWriter.java:256)
at javax.swing.text.html.MinimalHTMLWriter.writeHeader(MinimalHTMLWriter.java:220)
at javax.swing.text.html.MinimalHTMLWriter.write(MinimalHTMLWriter.java:122)
at javax.swing.text.html.HTMLEditorKit.write(HTMLEditorKit.java:293)
at javax.swing.text.DefaultEditorKit.write(DefaultEditorKit.java:152)
at numeracy.referencetextpanel.NRefButtonTextArea.getHTMLText(NRefButtonTextArea.java:328)
at numeracy.referencetextpanel.NInputPanelRefTextButton.getReferencedText(NInputPanelRefTextButton.java:59)
at numeracy.referencetextpanel.NInputRefText.actionPerformed(NInputRefText.java:106)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
My custom style is inserted like so (cID is a string like "{0-0}"):
StyledDocument doc = this.getStyledDocument();
NRefButton b = this.createRefButton(cID);
Style style = doc.addStyle(cID, null); //prepare a style
StyleConstants.setComponent(style, b);
doc.insertString(doc.getLength(), b.toString(), style); //insert button at index
The function createRefButton(String cID):
private NRefButton createRefButton(String cID) {
NRefButton b = new NRefButton(_equationButtons.get(cID).getText(), cID, _equationButtons.get(cID).isStruck()); //prepare a button
return b;
}
NRefButton overrides toString, which returns "{"+cID+"}".
What I would like to know: should I modify the way I insert the "Style" to get this error?
Is there a different/better way for me to get HTML from this JTextPane? All I want is HTML tags around bold/italic/underlined text, not overly complicated as if it is I'll then have to strip out the unnecessary HTML, and for the "style" to come out as button.toString().
Or should I implement my own toHTML() method, wrapping bold/italic/underlined text with the required tags? I don't mind doing this (in some ways I'd prefer it), but I don't know how to get the styles for the given JTextPane document. I suppose if I were able to get these styles, I could iterate through them, wrapping styled text in the appropriate tags?
Ideally, the pictured JTextPane content would be output as:
<html><p>This is some <b>styled</b> text. It is <u>incredible</u>.
<br/>
<br/>
Here we have a button that has been dropped in: {0-0}. These buttons are a <b><i>required part of this project.</i></b>
I want to be able to read the output HTML into the JTextPane as well - again I don't mind writing my own fromHTML() method for this, but I need to be able to get HTML out first.
Thank you for taking the time to read my question.
After reading:
I wrote my own HTML exporter:
package com.HTMLExport;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Element;
import javax.swing.text.ElementIterator;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;
public class NHTMLWriter {
private StyledDocument _sd;
private ElementIterator _it;
protected static final char NEWLINE = '\n';
public NHTMLWriter(StyledDocument doc) {
_sd = doc;
_it = new ElementIterator(doc.getDefaultRootElement());
}
public String getHTML(){
return "<html>" + this.getBody() + "</html>";
}
protected String getBody() {
/*
This will be a section element for a styled document.
We represent this element in HTML as the body tags.
Therefore we ignore it.
*/
_it.current();
Element next = null;
String body = "<body>";
while((next = _it.next()) != null) {
if (this.isText(next)) {
body += writeContent(next);
}
else if(next.getName().equals("component")){
body += getText(next); //this is where the custom component is output.
}
}
body += "</body>";
return body;
}
/**
* Returns true if the element is a text element.
*/
protected boolean isText(Element elem) {
return (elem.getName() == AbstractDocument.ContentElementName);
}
protected String writeContent(Element elem){
AttributeSet attr = elem.getAttributes();
String startTags = this.getStartTag(attr);
String content = startTags + this.getText(elem) + this.getEndTag(startTags);
return content;
}
/**
* Writes out text
*/
protected String text(Element elem){
String contentStr = getText(elem);
if ((contentStr.length() > 0) && (contentStr.charAt(contentStr.length()-1) == NEWLINE)) {
contentStr = contentStr.substring(0, contentStr.length()-1) + "<br/>";
}
if (contentStr.length() > 0) {
return contentStr;
}
return contentStr;
}
protected String getText(Element elem){
try {
return _sd.getText(elem.getStartOffset(), elem.getEndOffset() - elem.getStartOffset()).replaceAll(NEWLINE+"", "<br/>");
} catch (BadLocationException e) {
e.printStackTrace();
}
return "";
}
private String getEndTag(String startTags) {
String[] startOrder = startTags.split("<");
String tags = "";
for(String s : startOrder){
tags = "</" + s + tags;
}
return tags;
}
private String getStartTag(AttributeSet attr) {
String tag = "";
if(StyleConstants.isBold(attr)){
tag += "<b>";
}
if(StyleConstants.isItalic(attr)){
tag += "<i>";
}
if(StyleConstants.isUnderline(attr)){
tag += "<u>";
}
return tag;
}
}
Now I need to write code so that it can do the reverse: converts the output HTML to a StyledDocument.
First, coffee.