/**
  * {@link android.support.v4.widget.DrawerLayout.DrawerListener} callback method. If you do not
  * use your ActionBarDrawerToggle instance directly as your DrawerLayout's listener, you should
  * call through to this method from your own listener object.
  *
  * @param drawerView The child view that was moved
  * @param slideOffset The new offset of this drawer within its range, from 0-1
  */
 @Override
 public void onDrawerSlide(View drawerView, float slideOffset) {
   float glyphOffset = mSlider.getOffset();
   if (slideOffset > 0.5f) {
     glyphOffset = Math.max(glyphOffset, Math.max(0.f, slideOffset - 0.5f) * 2);
   } else {
     glyphOffset = Math.min(glyphOffset, slideOffset * 2);
   }
   mSlider.setOffset(glyphOffset);
 }