code: public void setValidator(AutoCompleteTextView.Validator validator) {
          if(mAutoCompleteMode == AUTOCOMPLETE_MODE_NONE)
              return;
          ((AutoCompleteTextView)mInputView).setValidator(validator);
      }
docs: Sets the validator used to perform text validation.
  <p>Only work when autoComplete mode is {@link #AUTOCOMPLETE_MODE_SINGLE} or {@link #AUTOCOMPLETE_MODE_MULTI}</p>
  
  @param validator The validator used to validate the text entered in this widget.
  
  @see #getValidator()
  @see #performValidation()