listview、gradview滚动到最后时，滑动至顶部

listview、gradview滑动顶端、底部的判断及底部滑动至顶端

mPhotoWall.setOnScrollListener(new AbsListView.OnScrollListener() {
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {

            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

                if (firstVisibleItem==0){
                    //最顶部
                }

                if (firstVisibleItem+visibleItemCount>=totalItemCount){
                    //最底部
                    view.smoothScrollToPositionFromTop(0,0,2000);//2s内滑动到顶部
                }
            }
        });