HtmlUtils.java

package kr.kdev.dg1s.biowiki.util;

import android.content.Context;
import android.content.res.Resources;
import android.text.Html;
import android.text.SpannableStringBuilder;
import android.text.TextUtils;
import android.text.style.QuoteSpan;

import org.apache.commons.lang.StringEscapeUtils;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Created by nbradbury on 7/9/13.
 */
public class HtmlUtils {

    /*
     * removes html from the passed string - relies on Html.fromHtml which handles invalid HTML,
     * but it's very slow, so avoid using this where performance is important
     */
    public static String stripHtml(final String text) {
        if (TextUtils.isEmpty(text))
            return "";
        return Html.fromHtml(text).toString().trim();
    }

    /*
     * this is much faster than stripHtml() but should only be used when we know the html is valid
     * since the regex will be unpredictable with invalid html
     */
    public static String fastStripHtml(String text) {
        if (TextUtils.isEmpty(text))
            return text;

        // insert a line break before P tags unless the only one is at the start
        if (text.lastIndexOf("<p") > 0)
            text = text.replaceAll("<p(.|\n)*?>", "\n<p>");

        // convert BR tags to line breaks
        if (text.contains("<br"))
            text = text.replaceAll("<br(.|\n)*?>", "\n");

        // use regex to strip tags, then convert entities in the result
        return fastUnescapeHtml(text.replaceAll("<(.|\n)*?>", "").trim());
    }

    /*
     * convert html entities to actual Unicode characters - relies on commons apache lang
     */
    public static String fastUnescapeHtml(final String text) {
        if (text == null || !text.contains("&"))
            return text;
        return StringEscapeUtils.unescapeHtml(text);
    }

    /*
     * converts an R.color.xxx resource to an HTML hex color
     */
    public static String colorResToHtmlColor(Context context, int resId) {
        try {
            return String.format("#%06X", 0xFFFFFF & context.getResources().getColor(resId));
        } catch (Resources.NotFoundException e) {
            return "#000000";
        }
    }

    /*
     * remove <script>..</script> blocks from the passed string - added to project after noticing
     * comments on posts that use the "Sociable" plugin ( http://wordpress.org/plugins/sociable/ )
     * may have a script block which contains <!--//--> followed by a CDATA section followed by <!]]>,
     * all of which will show up if we don't strip it here (example: http://cl.ly/image/0J0N3z3h1i04 )
     * first seen at http://houseofgeekery.com/2013/11/03/13-terrible-x-men-we-wont-see-in-the-movies/
     */
    public static String stripScript(final String text) {
        if (text == null)
            return null;

        StringBuilder sb = new StringBuilder(text);
        int start = sb.indexOf("<script");

        while (start > -1) {
            int end = sb.indexOf("</script>", start);
            if (end == -1)
                return sb.toString();
            sb.delete(start, end + 9);
            start = sb.indexOf("<script", start);
        }

        return sb.toString();
    }

    /**
     * an alternative to Html.fromHtml() supporting <ul>, <ol>, <blockquote> tags and replacing Emoticons with Emojis
     */
    public static SpannableStringBuilder fromHtml(String source) {
        SpannableStringBuilder html;
        try {
            html = (SpannableStringBuilder) Html.fromHtml(source, null, new BWHtmlTagHandler());
        } catch (RuntimeException runtimeException) {
            // In case our tag handler fails
            html = (SpannableStringBuilder) Html.fromHtml(source, null, null);
            // Log the exception and text that produces the error
            try {
                JSONObject additionalData = new JSONObject();
                additionalData.put("input_text", source);
                BWMobileStatsUtil.trackException(runtimeException, BWMobileStatsUtil.StatsPropertyExceptionNoteParsing,
                        additionalData);
            } catch (JSONException jsonException) {
                AppLog.e(AppLog.T.UTILS, jsonException);
            }
        }
        Emoticons.replaceEmoticonsWithEmoji(html);
        QuoteSpan spans[] = html.getSpans(0, html.length(), QuoteSpan.class);
        for (QuoteSpan span : spans) {
            html.setSpan(new BWHtml.WPQuoteSpan(), html.getSpanStart(span), html.getSpanEnd(span), html.getSpanFlags(
                    span));
            html.removeSpan(span);
        }
        return html;
    }
}