question: private void onMainContentScrolled ( int currentY , int deltaY ) { if ( deltaY > actionBarAutoHideSensitivity ) { deltaY = actionBarAutoHideSensitivity ; } else if ( deltaY < - actionBarAutoHideSensitivity ) { deltaY = - actionBarAutoHideSensitivity ; } if ( Math . signum ( deltaY ) * Math . signum ( actionBarAutoHideSignal ) < 0 ) { actionBarAutoHideSignal = deltaY ; } else { actionBarAutoHideSignal += deltaY ; } boolean shouldShow = currentY < actionBarAutoHideMinY || ( actionBarAutoHideSignal <= - actionBarAutoHideSensitivity ) ; autoShowOrHideActionBar ( shouldShow ) ; }
target:  Indicates that the main content has scrolled (for the purposes of showing/hiding the action bar for the "action bar auto hide" effect). currentY and deltaY may be exact (if the underlying view supports it) or may be approximate indications: deltaY may be INT_MAX to mean "scrolled forward indeterminately" and INT_MIN to mean "scrolled backward indeterminately".  currentY may be 0 to mean "somewhere close to the start of the list" and INT_MAX to mean "we don't know, but not at the start of the list"