Android : Data And Format Them Using RegEx

I'm having three strings that I have to glue together.

I have an input string (string 1), which I have to run a regex (which has groups) on (string 2) and extract these groups to put them in a template (string 3) using backreferences.

A short example could be :

input: "foo1234bar5678"
regex: ".*?(d*).*?(d*).*"
template: "answer: $1 $2"

which should be expanded in "answer: 1234 5678".

I have been using java.util.regex.Pattern, but I can't figure out a way to do this with matchers. Obviously, replaceAll is not the expected behaviour, nor is append*.

Is there a way to do this nicely using the android API ?

EDIT:
Here is a basic implementation :

public static String genOutput(String regex, String input, String template) {
Pattern p = Pattern.compile(regex);
Matcher m = p.matcher(input);
if (m.find()) {
for (int i = 1; i <= m.groupCount(); i++) {
template = template.replaceAll("$" + i, m.group(in}} return template;}