RecycleView下拉

recyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
StaggeredGridLayoutManager manager = (StaggeredGridLayoutManager) recyclerView.getLayoutManager();
boolean isSlidingToLast = false;
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
if (newState == RecyclerView.SCROLL_STATE_IDLE){
//获取最后一个完全显示的ItemPosition
int[] lastVisiblePositions = manager.findLastVisibleItemPositions(new int[manager.getSpanCount()]);
int lastVisiblePos = getMaxElem(lastVisiblePositions);
int totalItemCount = manager.getItemCount();

              // 判断是否滚动到底部
              if (lastVisiblePos == (totalItemCount -1) && isSlidingToLast) {
                  //加载更多功能的代码
                  gsonToNet();

// Ln.e("howes right="+manager.findLastCompletelyVisibleItemPosition());
Toast.makeText(MainActivity.this,"加载更多",Toast.LENGTH_SHORT).show();

              }
          }

      }

      @Override
      public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
          super.onScrolled(recyclerView, dx, dy);
          //dx用来判断横向滑动方向，dy用来判断纵向滑动方向
          if(dy > 0){
              //大于0表示，正在向下滚动
              isSlidingToLast = true;
          }else{
              //小于等于0 表示停止或向上滚动
              isSlidingToLast = false;
          }
      }
  });

private int getMaxElem(int[] arr) {
int size = arr.length;
int maxVal = Integer.MIN_VALUE;
for (int i = 0; i < size; i++) {
if (arr[i]>maxVal)
maxVal = arr[i];
}
return maxVal;
}