private void resetPreMenuItem() {
   if (mPrevMenuItem != null) {
     mPrevMenuItem.setChecked(false);
   } else {
     mBottomNavigationView.getMenu().getItem(0).setChecked(false);
   }
 }
  public void changeToFour(View v) {
    //        activateNewButton(mBottomNavigationView, 3);

    resetPreMenuItem();
    mPrevMenuItem = mBottomNavigationView.getMenu().getItem(3);
    mPrevMenuItem.setChecked(true);
    mViewPager.setCurrentItem(3);
  }