Spanned as from Html.fromHtml, but with custom ClickableSpan for custom scheme

I have a TextView that displays some HTML code (images included, ImageGetter). The html is not mine, but I can ask them to include custom scheme links, maybe even tags.

Purpose: to display some dynamically generated content without the need to play with nested Android layouts.
Problem: some links must be handled in the application (new Fragment loaded).
Can't use a receiver for action.VIEW, since it's an Activity Intent, not a broadcast, and its use will be very contextual, so only a programmatically registered receiver would do.

I'm usingtextView.setText(Html.fromHtml(content.content, imageGetter, null). need everything to remain the same, except some spans should have my own onClick on it. I'm not very familiar with Spanned, so I see these options:

Edit the SpannableStringBuilder returned from Html.fromHtml, and replace the URLSpans I want with a custom ClickableSpan (how?)
As above, but copy everything to a new builder, exchanging the URLSpans for my own (how? append takes a CharSequence only, and I get RelativeSizeSpan, StyleSpan, ImageSpan, URLSpan...)
Create a Spanned manually. I can do it for the custom scheme, but how to duplicate the effect of Html.fromHtml (or close enough) for all else?

[edit] Thanks to MH. for the info. I had tried that before, but failed. Now that i returned to it, I found i had made an error, passing the wrong item to the 1st argument of setSpan.
If anyone's interested, i now use this:

public static interface OnSpanClickListener {
    void onClick(String url);
}
public static SpannableStringBuilder getSpannable(String source, ImageGetter imageGetter, String scheme, final OnSpanClickListener clickHandler){
    SpannableStringBuilder b = (SpannableStringBuilder) Html.fromHtml(source, imageGetter, null);
    for(URLSpan s : b.getSpans(0, b.length(), URLSpan.class)){
        String s_url = s.getURL();
        if(s_url.startsWith(scheme+"://")){
            URLSpan newSpan = new URLSpan(s_url.substring(scheme.length()+3)){
                public void onClick(View view) {
                    clickHandler.onClick(getURL());
                }
            };
            b.setSpan(newSpan, b.getSpanStart(s), b.getSpanEnd(s), b.getSpanFlags(s));
            b.removeSpan(s);
        }
    }
    return b;
}

(...)

body.setText(getSpannable(content.content, imageGetter, getResources().getString(R.string.poster_scheme), new OnSpanClickListener(){
public void onClick(String url) {
    // do whatever
}
}));

Solution

Option 1 is probably most straightforward and most of the hard work for it has already been done before. You've got the general idea correct: after the HTML has been processed, you can request all the generated URLSpan instances and loop through them. You can then replace it with a customized clickable span to get full controls over any of the span clicks.

In the example below, I'm just replacing every URLSpan with a simple extension of that class that takes the original url (actually, I should probably say 'uri') and replace its scheme part. I've left the actual onClick() logic unimplemented, but I'll leave that up to your imagination.

SpannableStringBuilder builder = ...
URLSpan[] spans = builder .getSpans(0, builder .length(), URLSpan.class);
for (URLSpan span : spans) {
    int start = builder .getSpanStart(span);
    int end = builder .getSpanEnd(span);
    s.removeSpan(span);
    span = new CustomURLSpan(span.getURL().replace("http://", "scheme://"));
    s.setSpan(span, start, end, 0);
}
textView.setText(builder);

As mentioned earlier, here the CustomURLSpan class is a simple extension of URLSpan that takes a url and overrides the onClick() method so our own logic can be executed there.

public class CustomURLSpan extends URLSpan {

    public CustomURLSpan(String url) {
        super(url);
    }

    @Override public void onClick(View widget) {
        // custom on click behaviour here
    }
}

Some related Q&A's that basically do a similar thing (might be helpful for some more inspiration):