Displaying emoticons in Android

Question

My IM app has to support emoticons. They are GIFs and have textual representations, which are used in the input box if the user selects one of them. But I'd like to display them as images after they have been sent.Currently my custom array adapter displays the sent message in a TextView of a row.

What is the proper method to display images dynamically based on the occurrence of their textual representation? Do I have to search for emoticon texts, and if one found, remove the TextView from the layout (relativeLayout fits most?) and add a TextView with the beginning of the IM, an ImageView with the emoticon and another TextView. If more emoticons sent simultaneously it can be messy.

Is there an easier and more logical way?

Answer 1

I would try using a regular expression to replace all occurrences of each emoticon with an <img> tag. Then, convert that HTML into a SpannedString via Html.fromHtml(). That SpannedString can be used in a setText() call on TextView.

Answer 2

I think it would be more useful to build Spannable.

private static final Factory spannableFactory = Spannable.Factory
        .getInstance();

private static final Map<Pattern, Integer> emoticons = new HashMap<Pattern, Integer>();

static {
    addPattern(emoticons, ":)", R.drawable.emo_im_happy);
    addPattern(emoticons, ":-)", R.drawable.emo_im_happy);
    // ...
}

private static void addPattern(Map<Pattern, Integer> map, String smile,
        int resource) {
    map.put(Pattern.compile(Pattern.quote(smile)), resource);
}

public static boolean addSmiles(Context context, Spannable spannable) {
    boolean hasChanges = false;
    for (Entry<Pattern, Integer> entry : emoticons.entrySet()) {
        Matcher matcher = entry.getKey().matcher(spannable);
        while (matcher.find()) {
            boolean set = true;
            for (ImageSpan span : spannable.getSpans(matcher.start(),
                    matcher.end(), ImageSpan.class))
                if (spannable.getSpanStart(span) >= matcher.start()
                        && spannable.getSpanEnd(span) <= matcher.end())
                    spannable.removeSpan(span);
                else {
                    set = false;
                    break;
                }
            if (set) {
                hasChanges = true;
                spannable.setSpan(new ImageSpan(context, entry.getValue()),
                        matcher.start(), matcher.end(),
                        Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
            }
        }
    }
    return hasChanges;
}

public static Spannable getSmiledText(Context context, CharSequence text) {
    Spannable spannable = spannableFactory.newSpannable(text);
    addSmiles(context, spannable);
    return spannable;
}

Actualy this code based on sources from native Html class.

Edit: Updated version has dramatic speed improvement.