code: public void enableScrollInViewPager(ViewPager pager) {
          viewPager = pager;
          //noinspection all - ViewPager is not clickable, it is safe to set touch listener
          pager.setOnTouchListener(PAGER_TOUCH_LISTENER);
  
          // Disabling motion event splitting
          pager.setMotionEventSplittingEnabled(false);
      }
docs: Enables scroll inside {@link ViewPager}
  (by enabling cross movement between ViewPager and it's child view).
  
  @param pager Target ViewPager