/**
   * Get the phone number that raised this activity.
   *
   * @return The phone number we are trying to call with this activity
   */
  public String getPhoneNumber() {
    if (phoneNumber == null) {
      Intent it = getIntent();
      // Use utility function to extract number
      phoneNumber = UriUtils.extractNumberFromIntent(it, this);

      // Additional check to know if a csip uri (so that no rewriting rules applies)
      if (phoneNumber != null) {
        String action = it.getAction();
        Uri data = it.getData();
        if (!Intent.ACTION_SENDTO.equalsIgnoreCase(action) && data != null) {
          String scheme = data.getScheme();
          if (scheme != null) {
            scheme = scheme.toLowerCase();
          }
          if (SCHEME_CSIP.equals(scheme)) {
            ignoreRewritingRules = true;
          }
        }
      }
      // Still null ... well make it empty.
      if (phoneNumber == null) {
        phoneNumber = "";
      }
      return phoneNumber;
    }

    return phoneNumber;
  }