we can't set in XML file but we can set as coding...
You have to use text spannable..
here is example..
String text = "Hi @@hello@@";
TextView.setText(setSpanBetweenTokens(text, "@@", new
ForegroundColorSpan(Color.RED)));
your setSpanBetweenTokens Method
public static CharSequence setSpanBetweenTokens(CharSequence text,
            String token, CharacterStyle... cs)
        {
            // Start and end refer to the points where the span will apply
            int tokenLen = token.length();
            int start = text.toString().indexOf(token) + tokenLen;
            int end = text.toString().indexOf(token, start);
        
if (start > -1 && end > -1)
      {               
          SpannableStringBuilder ssb = new SpannableStringBuilder(text);
          for (CharacterStyle c : cs)
              ssb.setSpan(c, start, end, 0);
          // Delete the tokens before and after the span
          ssb.delete(end, end + tokenLen);
          ssb.delete(start - tokenLen, start);
          text = ssb;
      }
      return text;
  }