Android Html parsing and FBReader - ebook parsing

Question

I am modifying code of FBReader. I want to parse few more tags and attributes like <'center> tag, isFullPage attribute, but I failed to find the classes and parsing methods. I found few packages for parsing, I tried to edit them but I didn't get any output. I tried to debug the code and also prints logs. But all time there is no logs.

   org.geometerplus.fbreader.formats.fb2, 
   org.geometerplus.fbreader.formats.html, 
   org.geometerplus.fbreader.formats.oeb, 
   org.geometerplus.fbreader.formats.pdb, 
   org.geometerplus.zlibrary.core.html,

HtmlReader.java (package - org.geometerplus.zlibrary.core.html) have implemented methods -

public void startDocumentHandler();
public void endDocumentHandler();
public void startElementHandler(String tag, int offset, ZLHtmlAttributeMap attributes);
public void endElementHandler(String tag);
public void byteDataHandler(byte[] ch, int start, int length);
public void entityDataHandler(String entity);

FBreader Source Code - site and github code.

Please help. Thank you!