获取ListView在Y轴的精确滑动距离(单位px)

listView.setOnScrollListener(new AbsListView.OnScrollListener() {

private SparseArray recordSp = new SparseArray(0);

private int mCurrentfirstVisibleItem = 0;

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}

@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,int totalItemCount) {
mCurrentfirstVisibleItem = firstVisibleItem;
View firstView = view.getChildAt(0);

if (null != firstView) {
ItemRecod itemRecord = recordSp.get(firstVisibleItem);
if (null == itemRecord) {
itemRecord = new ItemRecod();
}

itemRecord.height = firstView.getHeight();
itemRecord.top = firstView.getTop();
recordSp.append(firstVisibleItem, itemRecord);
}
Logd("lp-test", "滑动距离getScrollY()="+getScrollY());

}
});

private int getScrollY() {
int height = 0;
for (int i = 0; i < mCurrentfirstVisibleItem; i++) {
ItemRecod itemRecod = (ItemRecod) recordSp.get(i);
if (itemRecod != null) {
height += itemRecod.height;
}

}
ItemRecod itemRecod = (ItemRecod) recordSp.get(mCurrentfirstVisibleItem);
if (null == itemRecod) {
itemRecod = new ItemRecod();
}
return height - itemRecod.top;
}

public class ItemRecod {
int height = 0;
int top = 0;
}