public boolean shouldHandleRecyclerViewLoadingMore(RecyclerView recyclerView) {
if (mIsLoadingMore
|| mCurrentRefreshStatus == RefreshStatus.REFRESHING
|| mLoadMoreFooterView == null
|| mDelegate == null
|| recyclerView.getAdapter() == null
|| recyclerView.getAdapter().getItemCount() == 0) {
return false;
}
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager == null || manager.getItemCount() == 0) {
return false;
}
if (manager instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) manager;
if (layoutManager.findLastCompletelyVisibleItemPosition()
== recyclerView.getAdapter().getItemCount() - 1) {
return true;
}
} else if (manager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager layoutManager = (StaggeredGridLayoutManager) manager;
int[] out = layoutManager.findLastCompletelyVisibleItemPositions(null);
int lastPosition = layoutManager.getItemCount() - 1;
for (int position : out) {
if (position == lastPosition) {
return true;
}
}
}
return false;
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
currentScrollState = newState;
RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
if ((visibleItemCount > 0
&& currentScrollState == RecyclerView.SCROLL_STATE_IDLE
&& (lastVisibleItemPosition) >= totalItemCount - 1)) {
onBottom(); // Scroll to bottom
}
}
@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();
}
}
private void maybeFireLoadMore() {
if (hasLoadMoreFired) {
return;
}
if (!showShowLoadMore) {
return;
}
final RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
int firstVisibleItemPosition = findFirstVisibleItemPosition();
if (totalItemCount == 0) {
return;
}
if (firstVisibleItemPosition + visibleItemCount + bufferItems > totalItemCount) {
if (onLoadMoreListener != null) {
hasLoadMoreFired = true;
onLoadMoreListener.onLoadMore(adapter.getLastItem());
}
}
}
/**
* Returns the adapter item count.
*
* @return The total number on items in a layout manager
*/
public int getItemCount() {
return layoutManager == null ? 0 : layoutManager.getItemCount();
}