Android - TextView Support (ul/ol/li)

gistfile1.txt

import java.util.Vector;

import org.xml.sax.XMLReader;

import android.text.Editable;
import android.text.Html;
import android.text.Spannable;
import android.text.style.BulletSpan;
import android.text.style.LeadingMarginSpan;
import android.text.style.TypefaceSpan;
import android.util.Log;

/*
 * HTML.formHtml() Source Code : 
 * http://www.netmite.com/android/mydroid/frameworks/base/core/java/android/text/Html.java
 * http://stackoverflow.com/questions/3150400/html-list-tag-not-working-in-android-textview-what-can-i-do/16169511#16169511
 * http://mohammedlakkadshaw.com/blog/Handling_Custom_Tags_Using_Html.tagHandler().html#.V9FpmRB94Y3
 */
public class HtmlTagHandler implements Html.TagHandler {
  private int mListItemCount = 0;
    private Vector<String> mListParents = new Vector<String>();

    @Override
    public void handleTag(final boolean opening, final String tag, Editable output, final XMLReader xmlReader) {

        if (tag.equals("ul") || tag.equals("ol") || tag.equals("dd")) {
            if (opening) {
                mListParents.add(tag);
            } else mListParents.remove(tag);

            mListItemCount = 0;
        } else if (tag.equals("li") && !opening) {
            handleListTag(output);
        }
      else if(tag.equalsIgnoreCase("code")) {
    	  if(opening) {
    		  output.setSpan(new TypefaceSpan("monospace"), output.length(), output.length(), Spannable.SPAN_MARK_MARK);
    	  } else {
    		  Log.d("COde Tag","Code tag encountered");
    		 Object obj = getLast(output, TypefaceSpan.class);
    		 int where = output.getSpanStart(obj);
    		 
    		 output.setSpan(new TypefaceSpan("monospace"), where, output.length(), 0);
    	  }
      }
    	
    }

    private Object getLast(Editable text, Class kind) {
    	Object[] 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 void handleListTag(Editable output) {
        if (mListParents.lastElement().equals("ul")) {
            output.append("\n");
            String[] split = output.toString().split("\n");

            int lastIndex = split.length - 1;
            int start = output.length() - split[lastIndex].length() - 1;
            output.setSpan(new BulletSpan(15 * mListParents.size()), start, output.length(), 0);
        } else if (mListParents.lastElement().equals("ol")) {
            mListItemCount++;

            output.append("\n");
            String[] split = output.toString().split("\n");

            int lastIndex = split.length - 1;
            int start = output.length() - split[lastIndex].length() - 1;
            output.insert(start, mListItemCount + ". ");
            output.setSpan(new LeadingMarginSpan.Standard(15 * mListParents.size()), start, output.length(), 0);
        }
    }
}



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/*
 * https://bitbucket.org/Kuitsi/android-textview-html-list/src/69949bd63422aeeefb79c67398dc14aab8806416/app/src/main/java/fi/iki/kuitsi/listtest/MyTagHandler.java?at=master&fileviewer=file-view-default#cl-86
 */
package fi.iki.kuitsi.listtest;

import java.util.Stack;

import org.xml.sax.XMLReader;

import android.text.Editable;
import android.text.Html;
import android.text.Spanned;
import android.text.style.BulletSpan;
import android.text.style.LeadingMarginSpan;
import android.util.Log;

/**
 * Implements support for ordered and unordered lists in to Android TextView.
 *
 * Some code taken from inner class android.text.Html.HtmlToSpannedConverter. If you find this code useful,
 * please vote my answer at <a href="http://stackoverflow.com/a/17365740/262462">StackOverflow</a> up.
 */
public class MyTagHandler implements Html.TagHandler {
	/**
	 * Keeps track of lists (ol, ul). On bottom of Stack is the outermost list
	 * and on top of Stack is the most nested list
	 */
	Stack<String> lists = new Stack<String>();
	/**
	 * Tracks indexes of ordered lists so that after a nested list ends
	 * we can continue with correct index of outer list
	 */
	Stack<Integer> olNextIndex = new Stack<Integer>();
	/**
	 * List indentation in pixels. Nested lists use multiple of this.
	 */
	private static final int indent = 10;
	private static final int listItemIndent = indent * 2;
	private static final BulletSpan bullet = new BulletSpan(indent);

	@Override
	public void handleTag(boolean opening, String tag, Editable output, XMLReader xmlReader) {
		if (tag.equalsIgnoreCase("ul")) {
			if (opening) {
				lists.push(tag);
			} else {
				lists.pop();
			}
		} else if (tag.equalsIgnoreCase("ol")) {
			if (opening) {
				lists.push(tag);
				olNextIndex.push(Integer.valueOf(1)).toString();//TODO: add support for lists starting other index than 1
			} else {
				lists.pop();
				olNextIndex.pop().toString();
			}
		} else if (tag.equalsIgnoreCase("li")) {
			if (opening) {
				if (output.length() > 0 && output.charAt(output.length() - 1) != '\n') {
					output.append("\n");
				}
				String parentList = lists.peek();
				if (parentList.equalsIgnoreCase("ol")) {
					start(output, new Ol());
					output.append(olNextIndex.peek().toString() + ". ");
					olNextIndex.push(Integer.valueOf(olNextIndex.pop().intValue() + 1));
				} else if (parentList.equalsIgnoreCase("ul")) {
					start(output, new Ul());
				}
			} else {
				if (lists.peek().equalsIgnoreCase("ul")) {
					if ( output.charAt(output.length() - 1) != '\n' ) {
						output.append("\n");
					}
					// Nested BulletSpans increases distance between bullet and text, so we must prevent it.
					int bulletMargin = indent;
					if (lists.size() > 1) {
						bulletMargin = indent-bullet.getLeadingMargin(true);
						if (lists.size() > 2) {
							// This get's more complicated when we add a LeadingMarginSpan into the same line:
							// we have also counter it's effect to BulletSpan
							bulletMargin -= (lists.size() - 2) * listItemIndent;
						}
					}
					BulletSpan newBullet = new BulletSpan(bulletMargin);
					end(output,
						Ul.class,
						new LeadingMarginSpan.Standard(listItemIndent * (lists.size() - 1)),
						newBullet);
				} else if (lists.peek().equalsIgnoreCase("ol")) {
					if ( output.charAt(output.length() - 1) != '\n' ) {
						output.append("\n");
					}
					int numberMargin = listItemIndent * (lists.size() - 1);
					if (lists.size() > 2) {
						// Same as in ordered lists: counter the effect of nested Spans
						numberMargin -= (lists.size() - 2) * listItemIndent;
					}
					end(output,
						Ol.class,
						new LeadingMarginSpan.Standard(numberMargin));
				}
			}
		} else {
			if (opening) Log.d("TagHandler", "Found an unsupported tag " + tag);
		}
	}

	/** @see android.text.Html */
	private static void start(Editable text, Object mark) {
		int len = text.length();
		text.setSpan(mark, len, len, Spanned.SPAN_MARK_MARK);
	}

	/** Modified from {@link android.text.Html} */
	private static void end(Editable text, Class<?> kind, Object... replaces) {
		int len = text.length();
		Object obj = getLast(text, kind);
		int where = text.getSpanStart(obj);
		text.removeSpan(obj);
		if (where != len) {
			for (Object replace: replaces) {
				text.setSpan(replace, where, len, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
			}
		}
		return;
	}

	/** @see android.text.Html */
	private static Object getLast(Spanned text, Class<?> kind) {
		/*
		 * This knows that the last returned object from getSpans()
		 * will be the most recently added.
		 */
		Object[] objs = text.getSpans(0, text.length(), kind);
		if (objs.length == 0) {
			return null;
		}
		return objs[objs.length - 1];
	}

	private static class Ul { }
	private static class Ol { }

}

not working for me. i have to show orderlist with number

Tag parameter always be "html" or "body" for handleTag method. Not be "li" or "lu".

Android got support for ul and li tags in Android N. They are supported tags, so they are no longer sent to the TagHandler.

Hi How do you indent/add margin to a list?