Android Jsoup change font-family in style tag

Question

I need to change font-family to a custom one after loading html into WebView. Basically I need to get this:

 <style>
            @font-face {
            font-family: 'MyFont';
            src: url('file:///android_asset/Custom-Font.otf')
            }
            body { font-family: 'MyFont', serif; font-size: 17px; color: #000; }
            a { color: #000; }
 </style>

from

<style>
            body { font-family: 'Helvetica', serif; font-size: 17px; color: #000; }
            a { color: #000; }
</style>

Html is dynamically loaded, not from assets. I use Jsoup, but cannot get this font-family parameter so far...

Answer 1

JSoup does not parse the CSS for you. It ends up in a DataNode hanging off the style element. From there, you are on your own in terms of parsing. If you have a simple search and replace, you can use a regular expression to do the work. For complicated situations, you can look at a [CSS Parser][1]. Your situation looks relatively simple, but given just one exemplar it is hard to tell which elements you want preserved. Here is a sketch of the basic idea, you may need to modify to fully fit your situation. The basic idea is to get the DataNode from the Style tag and using a regex to search and replace the field.

final String newFontInfo = "@font-face { \n"
        + "font-family: 'MyFont';\n"
        + "src: url('file:///android_asset/Custom-Font.otf')\n" + "}\n";
Elements styles = doc.select("style");
for (Element style : styles) {
    for (DataNode data : style.dataNodes()) {
        String dataTxt = data.getWholeData();
        if (dataTxt.contains("font-family")) {
             final String newData = dataTxt.replaceAll("font-family:\\s*'[^']*'","font-family: 'MyFont'");
             data.setWholeData(newFontInfo + newData);
        }
     }
 }