@Override
public int getItemsVisible(RecyclerView recyclerView) {
if (recyclerView == null) return 0;
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
if (!(layoutManager instanceof LinearLayoutManager)) {
throw new RuntimeException("LlScrollPercentCalculator needs a LinearLayoutManager.");
}
LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
return linearLayoutManager.findLastCompletelyVisibleItemPosition()
- linearLayoutManager.findFirstCompletelyVisibleItemPosition();
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int lastVisibleItem = 0;
int firstVisibleItem = 0;
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
int totalItemCount = layoutManager.getItemCount();
if (layoutManager instanceof LinearLayoutManager) {
LinearLayoutManager linearLayoutManager = ((LinearLayoutManager) layoutManager);
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
firstVisibleItem = linearLayoutManager.findFirstCompletelyVisibleItemPosition();
} else if (layoutManager instanceof GridLayoutManager) {
GridLayoutManager gridLayoutManager = ((GridLayoutManager) layoutManager);
// 通过LayoutManager找到当前显示的最后的item的position
lastVisibleItem = gridLayoutManager.findLastVisibleItemPosition();
firstVisibleItem = gridLayoutManager.findFirstCompletelyVisibleItemPosition();
} else if (layoutManager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager staggeredGridLayoutManager =
((StaggeredGridLayoutManager) layoutManager);
// 因为StaggeredGridLayoutManager的特殊性可能导致最后显示的item存在多个，所以这里取到的是一个数组
// 得到这个数组后再取到数组中position值最大的那个就是最后显示的position值了
int[] lastPositions = new int[((StaggeredGridLayoutManager) layoutManager).getSpanCount()];
staggeredGridLayoutManager.findLastVisibleItemPositions(lastPositions);
lastVisibleItem = findMax(lastPositions);
firstVisibleItem = staggeredGridLayoutManager.findFirstVisibleItemPositions(lastPositions)[0];
}
if (firstVisibleItem == 0) {
if (!mPullLoadMoreRecyclerView.isLoadMore()) {
mPullLoadMoreRecyclerView.setPullRefreshEnable(true);
}
} else {
mPullLoadMoreRecyclerView.setPullRefreshEnable(false);
}
/** 无论水平还是垂直 */
if (!mPullLoadMoreRecyclerView.isRefresh()
&& mPullLoadMoreRecyclerView.isHasMore()
&& (lastVisibleItem >= totalItemCount - 1)
&& !mPullLoadMoreRecyclerView.isLoadMore()
&& (dx > 0 || dy > 0)) {
mPullLoadMoreRecyclerView.setIsLoadMore(true);
mPullLoadMoreRecyclerView.loadMore();
}
}
@Override
public float getScrollPercentage(RecyclerView recyclerView) {
if (recyclerView == null) return 0;
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
if (!(layoutManager instanceof LinearLayoutManager)) {
throw new RuntimeException("LlScrollPercentCalculator needs a LinearLayoutManager.");
}
LinearLayoutManager linearLayoutManager = (LinearLayoutManager) layoutManager;
float lastFullyVisiblePosition = linearLayoutManager.findFirstVisibleItemPosition();
float visibleItems =
linearLayoutManager.findLastCompletelyVisibleItemPosition()
- linearLayoutManager.findFirstCompletelyVisibleItemPosition();
RecyclerView.Adapter adapter = recyclerView.getAdapter();
if (adapter == null) return 0;
float itemCount = adapter.getItemCount();
return lastFullyVisiblePosition / (itemCount - visibleItems);
}