code: private void updateEditorTextCount() {
          if (mMentionsEditText != null && mTextCounterView != null) {
              int textCount = mMentionsEditText.getMentionsText().length();
              mTextCounterView.setText(String.valueOf(textCount));
  
              if (mTextCountLimit > 0 && textCount > mTextCountLimit) {
                  mTextCounterView.setTextColor(mBeyondCountLimitTextColor);
              } else {
                  mTextCounterView.setTextColor(mWithinCountLimitTextColor);
              }
          }
      }
docs: Updates the TextView counting the number of characters in the editor. Sets not only the content
  of the TextView, but also the color of the text depending if the limit has been reached.