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

Question

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 using`textView.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` ta…

Accepted Answer

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):

- Can I change TextView link text after using Linkify?

- Remove underline from links in TextView - Android

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

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