Question

问题基于特定用例，如下所示： 1）转到列表末尾并加载更多数据，直到API返回空列表 2）之后调用refresh（）并刷新布局，但问题是在调用refresh（）之后，loadmore（）没有被调用。

我使用过SuperListView，我使用了EndlessScrollListener和官方SwipeToRefreshLayout，但没有任何效果。

我可能会以错误的方式使用适配器，但下面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，但这可能与我无关，对于后端我使用的是Spring + Android Annotations + [Observer + Facade]设计模式。

提前致谢。

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
}
}

Answer 1

您可以覆盖listView方法，例如此片段：

 @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);
        }
    }

您正在检测的行totalCount != totalLoadedCount && firstVisible + visibleCount >= totalCount;中的位置，如果listView已滚动到底部，getContent(dto.loadedCount);是方法，则会将新数据加载到列表中。

完整教程为here。

带有Refresh和LoadMore选项的ListView不起作用

1 个答案: