我正在关注this教程实施分页，我正在密切关注它，但我不确定如何修改我当前的活动以实现OnLoadMoreListener。我正在使用改造中的ApiService来加载数据，这与生成随机字符串的教程不同。
这是我当前的RecyclerView适配器的样子：
public class CuratedSectionAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static int VIEW_TYPE_HEADER = 0;
private static int VIEW_TYPE_ITEM = 1;
private static int VIEW_TYPE_LOADING = 2;
private int lastVisibleItem, totalItemCount;
private int visibleThreshold = 2;
private boolean isLoading;
private List<Object> itemList;
private OnLoadMoreListener onLoadMoreListener;
public CuratedSectionAdapter(RecyclerView recyclerView, List<Object> itemList) {
this.itemList = itemList;
final LinearLayoutManager linearLayoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
if (onLoadMoreListener != null) {
onLoadMoreListener.onLoadMore();
}
isLoading = true;
}
}
});
}
private class ItemViewHolder extends RecyclerView.ViewHolder {
RecyclerView itemRecyclerView;
CuratedSectionNestedAdapter nestedAdapter;
LinearLayoutManager layoutManager;
ItemViewHolder(View view) {
super(view);
itemRecyclerView = view.findViewById(R.id.recyclerView_nested);
layoutManager = new LinearLayoutManager(view.getContext(), LinearLayoutManager.HORIZONTAL, false);
}
}
private class HeaderViewHolder extends RecyclerView.ViewHolder {
TextView textViewHeader;
Typeface montserratMedium = Typeface.createFromAsset(getApplicationContext().getAssets(), "fonts/Montserrat-Medium.ttf");
HeaderViewHolder(View view) {
super(view);
textViewHeader = view.findViewById(R.id.textView_header);
textViewHeader.setTypeface(montserratMedium);
}
}
private class LoadingViewHolder extends RecyclerView.ViewHolder {
public ProgressBar progressBar;
public LoadingViewHolder(View view) {
super(view);
progressBar = (ProgressBar) view.findViewById(R.id.progress_bar);
}
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder.getItemViewType() == VIEW_TYPE_HEADER) {
HeaderViewHolder viewHolder = (HeaderViewHolder) holder;
CuratedSectionHeader header = (CuratedSectionHeader) itemList.get(position);
viewHolder.textViewHeader.setText(header.getHeaderName());
} else if (holder.getItemViewType() == VIEW_TYPE_ITEM) {
ItemViewHolder viewHolder = (ItemViewHolder) holder;
List<CuratedSectionItem> items = (List<CuratedSectionItem>) itemList.get(position);
if (viewHolder.nestedAdapter != null) {
viewHolder.nestedAdapter.setItems(items);
} else {
viewHolder.nestedAdapter = new CuratedSectionNestedAdapter(items);
viewHolder.itemRecyclerView.setLayoutManager(viewHolder.layoutManager);
viewHolder.itemRecyclerView.setAdapter(viewHolder.nestedAdapter);
}
} else if (holder.getItemViewType() == VIEW_TYPE_LOADING) {
LoadingViewHolder loadingViewHolder = (LoadingViewHolder) holder;
loadingViewHolder.progressBar.setIndeterminate(true);
}
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_HEADER) {
return new HeaderViewHolder(LayoutInflater.from(parent.getContext())
.inflate(R.layout.main_explore_header_row, parent, false));
} else if (viewType == VIEW_TYPE_ITEM) {
return new ItemViewHolder(LayoutInflater.from(parent.getContext())
.inflate(R.layout.main_explore_row, parent, false));
} else if (viewType == VIEW_TYPE_LOADING) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_loading, parent, false);
return new LoadingViewHolder(view);
}
throw new RuntimeException("Adapter " + viewType + "not found");
}
@Override
public int getItemCount() {
return itemList.size();
}
@Override
public int getItemViewType(int position) {
if (itemList.get(position) instanceof CuratedSectionHeader) {
return VIEW_TYPE_HEADER;
} else {
return itemList.get(position) == null ? VIEW_TYPE_LOADING : VIEW_TYPE_ITEM;
}
}
public void setOnLoadMoreListener(OnLoadMoreListener mOnLoadMoreListener) {
this.onLoadMoreListener = mOnLoadMoreListener;
}
public void setLoaded() {
isLoading = false;
}
}
我的活动的当前架构使用私有类来进行API调用并加载数据。目前，所有商品都会立即加载，但理想情况下，一次只能加载2件商品。当我滚动到底部时，我不确定如何通过再次调用API服务来加载其他项目。至少，我确信我必须以某种方式使用curatedSectionAdapter.setOnLoadMoreListener。
这就是我现在加载所有项目的方式：
private class Sections {
List<CuratedSection> sections = new ArrayList<>();
public Thread[] thread;
private Sections() {}
public void setSections(ArrayList<CuratedSection> sections) {
this.sections = sections;
}
public void setSectionStories(String sectionId, List<CuratedSectionItem> stories) {
for(CuratedSection s : sections){
if(s.id != null && s.id.equals(sectionId)) {
s.stories = stories;
}
}
}
public void loadStories(String sessionKey) {
thread = new Thread[sections.size()];
for( int s = 0; s < sections.size(); s++) {
thread[s] = new Thread(new LoadStories(sessionKey, sections.get(s)));
thread[s].start();
}
for( int f = 0; f < sections.size(); f++) {
try {
thread[f].join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
recyclerView.setLayoutManager(layoutManager);
curatedSectionAdapter = new CuratedSectionAdapter(recyclerView, this.getAdapterInfo());
recyclerView.setAdapter(curatedSectionAdapter);
}
public void loadSections(int numSections) {
swipeRefreshLayout.setRefreshing(false);
LoadSections load = new LoadSections(numSections);
load.run();
}
public List<Object> getAdapterInfo() {
List<Object> list = new ArrayList<>();
for (int i = 0; i < sections.size(); i++) {
CuratedSection section = sections.get(i);
CuratedSectionHeader header = new CuratedSectionHeader();
header.setHeaderName(section.header);
list.add(header);
list.add(section.stories);
}
return list;
}
}
private class LoadSections implements Runnable {
int numSections;
LoadSections(int numSections) {
this.numSections = numSections;
}
@Override
public void run() {
SharedPreferences prefs = getSharedPreferences("user_session", MODE_PRIVATE);
final String sessionKey = prefs.getString("session_key", null);
Call<JsonArray> call;
call = TravelersApi.endpoint().getCuratedSections(sessionKey);
call.enqueue(new Callback<JsonArray>() {
@Override
public void onResponse(Call<JsonArray> call, Response<JsonArray> response) {
if(response.code() != 200) {
Toast.makeText(getApplicationContext(), "Cannot load page as of the moment.", Toast.LENGTH_SHORT).show();
return;
}
JsonArray rawSections = response.body();
if(rawSections.size() == 0) {
//TODO: show placeholder
return;
}
ArrayList<CuratedSection> sections = new ArrayList<>();
for(int i = 0; i < numSections; i++) {
JsonObject jSection = rawSections.get(i).getAsJsonObject();
final CuratedSection section = new CuratedSection();
section.id = jSection.get("id").getAsString();
section.header = jSection.get("section_header").getAsString();
section.topicCount = jSection.get("topic_count").getAsInt();
section.isShown = jSection.get("is_shown").getAsBoolean();
section.stories = new ArrayList<>();
sections.add(section);
}
curated.setSections(sections);
curated.loadStories(sessionKey);
spinner.clearAnimation();
spinner.setVisibility(View.GONE);
header.setVisibility(View.VISIBLE);
swipeRefreshLayout.setVisibility(View.VISIBLE);
}
@Override
public void onFailure(Call<JsonArray> call, Throwable t) {
Log.d("ERROR!", t.toString());
t.printStackTrace();
}
});
}
}
答案 0 :(得分：2)
您可以通过直接将滚动侦听器设置为您的回收站视图来实现此目的。
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
totalItemCount = linearLayoutManager.getItemCount();
lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();
if (!isLoading && totalItemCount <= (lastVisibleItem + visibleThreshold)) {
// Call Load more method here to load next page data
// Prevent multiple calls by using a boolean
isLoading=true; // boolean to Prevent multiple calls
}
}
});
OnLoadMoreListener 是您首先需要注册的界面。 对于分页，您的服务器应该处理分页计数。所以你还需要api来执行页面限制。