private void beginGesture(int scrollOffsetY,int scrollExtentY){
  mInitialTranslationY=getTranslationY();
  boolean isInitiallyVisible=mInitialTranslationY < mTotalHeight;
  int startingY=isInitiallyVisible ? scrollOffsetY : Math.min(scrollOffsetY,mTotalHeight);
  mInitialOffsetY=startingY + scrollExtentY;
}

private void beginGesture ( int scrollOffsetY , int scrollExtentY ) { mInitialTranslationY = getTranslationY ( ) ; boolean isInitiallyVisible = mInitialTranslationY < mTotalHeight ; int startingY = isInitiallyVisible ? scrollOffsetY : Math . min ( scrollOffsetY , mTotalHeight ) ; mInitialOffsetY = startingY + scrollExtentY ; }
records the conditions of the page when a gesture is initiated .
