Several ways. You can use Element#append() to
append some piece of HTML to the element.
Document document = Jsoup.connect(url).get();
Element head = document.head();
head.append("<link rel=\"stylesheet\" href=\"http://example.com/your.css\">");
Or, use Element#attr(name,
value) to add attributes to existing elements. Here's an example which adds style="color:pink;" to
all links.
Document document = Jsoup.connect(url).get();
Elements links = document.select("a");
links.attr("style", "color:pink;");
Either way, after modification get the final HTML string by Document#html().
String html = document.html();
Write it to file by PrintWriter#write() (with
the right charset).
String charset = Jsoup.connect(url).response().charset();
// ...
Writer writer = new PrintWriter("/file.html", charset);
writer.write(html);
writer.close();Finally open it in the webview. Since I can't tell it from top of head, here's just a link with an example which I think is helpful: WebViewDemo.java. I found the link on this blog by the way (which I in turn found by Google).