Style text of parameter in getString(int resId, Object... formatArgs) method
It's a bit tricky. Converting back to charsequence (String feedback = getString(R.string.give_us_feedback, email);
) makes disappear the Spannable
. Try this way (you want to check for the correct indexes in your string)
String emailString = getString(R.string.email);
String feedback = getString(R.string.give_us_feedback, emailString);
SpannableString email = new SpannableString(feedback);
int startIndex = feedBack.indexOf(emailString);
int endIndex = startIndex + emailString.length();
email.setSpan(new UnderlineSpan(), startIndex, endIndex, 0);
email.setSpan(new ForegroundColorSpan(Color.BLUE), startIndex, endIndex, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
emailTV.setText(email);