Extract attributes from XmlReader in Android HtmlTagHandler

HtmlTagHandler.java

public class HtmlTagHandler implements Html.TagHandler {
  private static final String TAG = HtmlTagHandler.class.getSimpleName();

  @Override
    public void handleTag(final boolean opening, final String tag, Editable output, final XMLReader xmlReader) {
        if(opening) {
          if(tag.equalsIgnoreCase("a")) {
             start(output, new A(getAttribute("href", xmlReader, "error.com")));
          }
        } else {
          if(tag.equalsIgnoreCase("a")) {
            A obj = getLast(output, A.class);
            // start of the tag
            int where = output.getSpanStart(obj);
            // end of the tag
            int len = output.length();
            
            //TODO-
            //Do something with your attribute
          }
        }
    }
  
  private void start(Editable output, Object mark) {
        final int len = output.length();
        output.setSpan(mark, len, len, Spannable.SPAN_MARK_MARK);
  }

    /**
     * Modified from {@link android.text.Html}
     */
    private void end(Editable output, Class kind, boolean paragraphStyle, Object... replaces) {
        Object obj = getLast(output, kind);
        // start of the tag
        int where = output.getSpanStart(obj);
        // end of the tag
        int len = output.length();
      
        output.removeSpan(obj);

        if(where != len) {
            int thisLen = len;
            // paragraph styles like AlignmentSpan need to end with a new line!
            if(paragraphStyle) {
                output.append("\n");
                thisLen++;
            }
            for(Object replace : replaces) {
                output.setSpan(replace, where, thisLen, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
            }
        }
    }

    /**
     * Returns the text contained within a span and deletes it from the output string
     */
    private CharSequence extractSpanText(Editable output, Class kind) {
        final Object obj = getLast(output, kind);
        // start of the tag
        final int where = output.getSpanStart(obj);
        // end of the tag
        final int len = output.length();

        final CharSequence extractedSpanText = output.subSequence(where, len);
        output.delete(where, len);
        return extractedSpanText;
    }

  
    private static <T> T getLast(Editable text, Class<T> kind) {
        final T[] objs = text.getSpans(0, text.length(), kind);
        if(objs.length == 0) {
            return null;
        } else {
            for(int i = objs.length; i > 0; i--) {
                if(text.getSpanFlags(objs[i - 1]) == Spannable.SPAN_MARK_MARK) {
                    return objs[i - 1];
                }
            }
            return null;
        }
    }
  
    private static String getAttribute(@NonNull String attr, @NonNull XMLReader reader, String defaultAttr) {
          try {
              final Field elementField = reader.getClass().getDeclaredField("theNewElement");
              elementField.setAccessible(true);
              final Object element = elementField.get(reader);
              final Field attsField = element.getClass().getDeclaredField("theAtts");
              attsField.setAccessible(true);
              final Object atts = attsField.get(element);
              final Field dataField = atts.getClass().getDeclaredField("data");
              dataField.setAccessible(true);
              final String[] data = (String[]) dataField.get(atts);
              final Field lengthField = atts.getClass().getDeclaredField("length");
              lengthField.setAccessible(true);
              final int len = (Integer) lengthField.get(atts);
              for(int i = 0; i < len; i++) {
                  if(attr.equals(data[i * 5 + 1])) {
                      return data[i * 5 + 4];
                  }
              }
          } catch(Exception e) {
              Log.e(TAG, "handleTag: ", e);
          }
          return defaultAttr;
      }

    private static class A {
        String href;

        A(String href) {
           this.href = href;
        }
    }
  
}