问题基于一个特定的用例,如下所示:1) 转到列表的末尾并加载更多数据,直到API返回一个空列表2) 在调用refresh()之后,布局将刷新,但问题是在我调用refresh()之后不会调用loadmore()。
我使用过SuperListView,我使用过官方SwipeToRefreshLayout的EndlessScrollListener,但都不起作用。
我想我可能以错误的方式使用适配器,但以下是我正在使用的代码片段:
void showContent(){
contentListModel = ((ContentListModel) baseModel);
contentAdapter = ContentAdapter(getActivity(),R.layout.content_item,contentListModel.getContents());
mListView.setAdapter(contentAdapter);
}
void showRefreshContent(){
contentListModel = new ContentListModel();
contentAdapter.clear();
contentListModel = ((ContentListModel) baseModel);
contentAdapter.addAll(contentListModel.getContents());
mListView.setAdapter(contentAdapter);
}
void showLoadMoreContent(){
contentListModel = ((ContentListModel) baseModel);
contentAdapter.addAll(contentListModel.getContents());
contentAdapter.notifyDataSetChanged();
}
我可以分享完整的代码,但我想这可能无关紧要,因为后端我使用的是Spring+AndroidAnnotations+[Obstator+Facade]设计模式。
提前谢谢。
EndlessScrollListener
public abstract class EndlessScrollListener implements AbsListView.OnScrollListener {
// The minimum amount of items to have below your current scroll position
// before loading more.
private int visibleThreshold = 8;
// The current offset index of data you have loaded
private int currentPage = 1;
// The total number of items in the dataset after the last load
private int previousTotalItemCount = 0;
// True if we are still waiting for the last set of data to load.
private boolean loading = true;
// Sets the starting page index
private int startingPageIndex = 0;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
public EndlessScrollListener(int visibleThreshold, int startPage) {
this.visibleThreshold = visibleThreshold;
this.startingPageIndex = startPage;
this.currentPage = startPage;
}
// This happens many times a second during a scroll, so be wary of the code you place here.
// We are given a few useful parameters to help us work out if we need to load some more data,
// but first we check if we are waiting for the previous load to finish.
@Override
public void onScroll(AbsListView view,int firstVisibleItem,int visibleItemCount,int totalItemCount)
{
// If the total item count is zero and the previous isn't, assume the
// list is invalidated and should be reset back to initial state
if (totalItemCount < previousTotalItemCount) {
this.currentPage = this.startingPageIndex;
this.previousTotalItemCount = totalItemCount;
if (totalItemCount == 0) { this.loading = true; }
}
// If it’s still loading, we check to see if the dataset count has
// changed, if so we conclude it has finished loading and update the current page
// number and total item count.
if (loading && (totalItemCount > previousTotalItemCount)) {
loading = false;
previousTotalItemCount = totalItemCount;
currentPage++;
}
// If it isn’t currently loading, we check to see if we have breached
// the visibleThreshold and need to reload more data.
// If we do need to reload some more data, we execute onLoadMore to fetch the data.
if (!loading && (totalItemCount - visibleItemCount)<=(firstVisibleItem + visibleThreshold)) {
onLoadMore(currentPage + 1, totalItemCount);
loading = true;
}
}
// Defines the process for actually loading more data based on page
public abstract void onLoadMore(int page, int totalItemsCount);
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
// Don't take any action on changed
}
}
您可以覆盖listView方法,如以下代码段所示:
@Override
public void onScrollStateChanged(AbsListView absListView, int i)
{
}
@Override
public void onScroll(AbsListView absListView, int firstVisible, int visibleCount, int totalCount)
{
boolean loadMore = totalCount != totalLoadedCount && firstVisible + visibleCount >= totalCount;
if (loadMore)
{
totalLoadedCount = totalCount;
getContent(dto.loadedCount);
}
}
在您正在检测的totalCount != totalLoadedCount && firstVisible + visibleCount >= totalCount;
行中,如果listView已滚动到底部,并且getContent(dto.loadedCount);
是方法,则会将新数据加载到列表中。
完整的教程在这里。