code: @Override
      public void onTextChanged(CharSequence s, int start, int before, int count) {
  
          if (findFocus() != null) {
              currentFocus = Integer.parseInt(findFocus().getTag().toString());
          }
  
          if (count == 1 && s.length() == mNumberCharacters) {
              if (currentFocus == (mNumberPinBoxes - 1) || currentFocus == 0) {
                  checkPinBoxesAvailableOrder();
              } else {
                  checkPinBoxesAvailable();
              }
  
          }
      }
docs: Check if you have written or have deleted (in the latter case, there would be to do nothing).
  If you have written, you have to move to the following free PinBox {@link EditText} or to do other
  action if there are no empty values.