ScrollView.getScrollY () always returns 0

Question

I want to know when my ScrollView scrolls up. This is what I tried:

  scrollView.getViewTreeObserver().addOnScrollChangedListener(new ViewTreeObserver.OnScrollChangedListener() { @Override public void onScrollChanged() { int scrollX = scrollView.getScrollX(); //for horizontalScrollView int scrollY = scrollView.getScrollY(); Log.d("TagFragment", "scrollY" + scrollY); mainFragment.setCanPullToRefresh(scrollY == 0); } }); 

The problem is this: scrollY is almost always 0. Therefore, it returns almost always true. Some values ​​are correct:

LogCat:

 D/TagFragment﹕ scrollY242 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY244 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY245 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY0 D/TagFragment﹕ scrollY246 D/TagFragment﹕ scrollY0 

How can I find out 100% what is offset?