public void setSectionName(String sectionName) {
        if (!sectionName.equals(mSectionName)) {
            mSectionName = sectionName;
            mTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTextBounds);
            // Update the width to use measureText since that is more accurate
            mTextBounds.right = (int) (mTextBounds.left + mTextPaint.measureText(sectionName));
        }
    }
Animates the visibility of the fast scroller popup.
android/third_party/recyclerview-fastscroll/src/main/java/com/simplecityapps/recyclerview_fastscroll/views/FastScrollPopup.java