我还没有找到适当的示例，说明如何在向下滚动RecyclerView时使应用程序从翻新onResponse中加载更多项目。
这是我如何装载拳头20件物品的方法：
List<ModelPartners> model = new ArrayList<>();
Call<ResponsePartners> call = ApiClient.getRetrofit().getPartnerList(params);
call.enqueue(this);
我的RecyclerView
PartnersAdapter adapter = new PartnersAdapter(getContext(), recyclerView, model);
recyclerView.setAdapter(adapter);
这是我的改造onResponse：
@Override
public void onResponse(Call<ResponsePartners> call, Response<ResponsePartners> response) {
if (getActivity() != null && response.isSuccessful()) {
List<ModelPartners> body = response.body().getData();
//Rest of the code to add body to my Adapter and notifyDataSetChanged
}
}
我的问题是，每次我添加滚动加载更多项目的方法时，onResponse会一直加载直到最后一页。即使我将loading设置为 false 。
有人可以显示如何在翻新中正确使用分页吗？您与Retrofit一起使用了哪些库，或向我展示了如何使用它？预先谢谢你
答案 0 :(得分：3)
您需要三件事来实现这一目标，您需要：
假设您在服务器上拥有这样的模型
public class PagedList<T> {
private int page = 0;
private List<T> results = new ArrayList<>();
private int totalResults = 0;
private int totalPages = 0;
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public List<T> getResults() {
return results;
}
public void setResults(List<T> results) {
this.results = results;
}
public int getTotalResults() {
return totalResults;
}
public void setTotalResults(int totalResults) {
this.totalResults = totalResults;
}
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
}
您的OnScroll侦听器：- 在您的活动中，这就是您想要的，所以在活动中添加第二种方法
public void onCreate(Bundle savedInstance) {
// setup your view components
// ...
// get the layout manager
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
// rest endpoint
apiEndpoint = retrofit.create(RetrofitEndpoint.class);
// initialise loading state
mIsLoading = false;
mIsLastPage = false;
// amount of items you want to load per page
final int pageSize = 20;
// set up scroll listener
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
// number of visible items
int visibleItemCount = layoutManager.getChildCount();
// number of items in layout
int totalItemCount = layoutManager.getItemCount();
// the position of first visible item
int firstVisibleItemPosition = layoutManager.findFirstVisibleItemPosition();
boolean isNotLoadingAndNotLastPage = !mIsLoading && !mIsLastPage;
// flag if number of visible items is at the last
boolean isAtLastItem = firstVisibleItemPosition + visibleItemCount >= totalItemCount;
// validate non negative values
boolean isValidFirstItem = firstVisibleItemPosition >= 0;
// validate total items are more than possible visible items
boolean totalIsMoreThanVisible = totalItemCount >= pageSize;
// flag to know whether to load more
boolean shouldLoadMore = isValidFirstItem && isAtLastItem && totalIsMoreThanVisible && isNotLoadingAndNotLastPage
if (shouldLoadMore) loadMoreItems(false);
}
});
// load the first page
loadMoreItems(true);
}
private void loadMoreItems(boolean isFirstPage) {
// change loading state
mIsLoading = true;
mCurrentPage = mCurrentPage + 1;
// update recycler adapter with next page
apiEndpoint.getPagedList(mCurrentPage).enqueue(new Callback<PagedList<Object>>() {
@Override
public void onResponse(Call<PagedList<Object>> call, Response<PagedList<Object>> response) {
PagedList<Object> result = response.body();
if (result == null) return;
else if (!isFirstPage) mAdapter.addAll(result.getResults());
else mAdapter.setList(result.getResults());
mIsLoading = false;
mIsLastPage = mCurrentPage == result.getTotalPages();
}
@Override
public void onFailure(Call<PagedList<Object>> call, Throwable t) {
Log.e("SomeActivity", t.getMessage());
}
});
}
回收站适配器：- 对于回收站适配器，您所需要做的就是添加一个将项目添加到其列表的方法，如下所示
public class SomeAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<Object> list;
// .. other overridden members
public void setList(List<Object> list) {
this.list = list;
notifyDataSetChanged();
}
public void addAll(List<Object> newList) {
int lastIndex = list.size() - 1;
list.addAll(newList);
notifyItemRangeInserted(lastIndex, newList.size());
}
}
然后，最后一个带页面的 retrofit界面，如下所示：
interface RetrofitEndpoint {
@GET("paged/list/endpoint")
Call<PagedList<Object>> getPagedList(@Query("page") int page);
}
希望有帮助。
答案 1 :(得分：2)
@Alimov Shohrukh，我还尝试了多种方法分页
1）Check this link,This is one way
2）我会逐步介绍它
从API端开始-您需要传递pageConunt，pageIndex并根据上述参数获取数据
pageConunt-表示要从服务器获取多少数据，即-10 pageIndex-例如1,2,3等的页码
public class DemoActivity extends BaseActivity{
List<BaseModel> orderList = new ArrayList<>();
ListAdapter listAdapter;
LinearLayoutManager layoutManager;
OrderListAdapter orderListAdapter;
int pageIndex = 1; // you can pass 1,2,3...
int pageCount = 10; //you can pass 10,20...
boolean isApiSuccess = false;
//if api get success == true then you need to work with load more sp we take one boolean variable
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_demo);
findView();
setRecyclerViewPagination();
}
private void findView() {
//recyclerview
rv_po_order_number = findViewById(R.id.rv_po_order_number);
}
//custom OnScrollListener
private RecyclerView.OnScrollListener recyclerViewOnScrollListener = new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (isApiSuccess) {
pageIndex++;
listTestApiCall(pageIndex, searchQuery);
Log.e(TAG, pageIndex + " page count ");
orderListAdapter.showLoading(true);
rv_po_order_number.post(new Runnable() {
public void run() {
// There is no need to use notifyDataSetChanged()
orderListAdapter.notifyDataSetChanged();
}
});
}
}
};
private void setRecyclerViewPagination() {
orderList = new ArrayList<>();
orderListAdapter = new OrderListAdapter(mActivity, orderList);
layoutManager = new LinearLayoutManager(mActivity, LinearLayoutManager.VERTICAL, false);
rv_po_order_number.setLayoutManager(layoutManager);
rv_po_order_number.setHasFixedSize(true);
rv_po_order_number.setAdapter(orderListAdapter);
rv_po_order_number.addOnScrollListener(recyclerViewOnScrollListener);
listTestApiCall(pageCount,pageIndex);
}
private void listTestApiCall(final int pageCount,final int pageIndex) {
// if (CommonUtils.isConnectingToInternet(mActivity)) {
if (validateInternetConn(mActivity)) {//check internet
final boolean isFirstPage = pageIndex == 1 ? true : false;
if (isFirstPage)
//do your stuff - if you want to show loader
Call<BaseModel> call = ApiClient.getClient().listApiCall(pageCount, pageIndex);
call.enqueue(new Callback<BaseModel>() {
@Override
public void onResponse(Call<BaseModel> call, Response<BaseModel> response) {
try {
if (response.isSuccessful()) {
boolean success = response.body().getStatus();
isApiSuccess = response.body().getStatus();
if (success) {
List<BaseModel> list = new ArrayList<>();
if (response.body().getData() != null) {
list = response.body().getData();
if (isFirstPage)
orderList.clear();
orderList.addAll(response.body().getData());
}
if (list != null && list.size() > 0) {
isApiSuccess = true;
} else {
isApiSuccess = false;
}
} else if (!success) {
isApiSuccess = false;
String message = response.body().getMessage();
}
listAdapter.showLoading(false);
listAdapter.notifyDataSetChanged();
}
} catch (Exception e) {
e.printStackTrace();
Log.e("Tag", "error=" + e.toString());
isApiSuccess = false;
}
}
@Override
public void onFailure(Call<BaseModel> call, Throwable t) {
Log.e("Tag", "error" + t.toString());
isApiSuccess = false;
}
});
}
}
}
这里是OrderListAdapter
public class OrderListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder>{
Activity mActivity;
List<OrderListBaseModel.DataBean> mList;
PurchaseOrderReceiveOnClick purchaseOrderReceiveOnClick;
DeleteUpdatePOOnClick deleteUpdatePOOnClick;
public static final int TYPE_FOOTER = 1;
public static final int TYPE_ITEM = 2;
protected boolean showLoader = true;
public OrderListAdapter(Activity mActivity, List<OrderListBaseModel.DataBean> mList, PurchaseOrderReceiveOnClick purchaseOrderReceiveOnClick,DeleteUpdatePOOnClick deleteUpdatePOOnClick) {
this.mActivity = mActivity;
this.purchaseOrderReceiveOnClick = purchaseOrderReceiveOnClick;
this.deleteUpdatePOOnClick = deleteUpdatePOOnClick;
this.mList = mList;
}
public OrderListAdapter(Activity mActivity, List<OrderListBaseModel.DataBean> mList) {
this.mActivity = mActivity;
this.mList = mList;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == TYPE_ITEM) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.row_purchase_order_receive, parent, false);
return new DataViewHolder(v, purchaseOrderReceiveOnClick);
} else if (viewType == TYPE_FOOTER) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.loading_layout, parent, false);
return new FooterViewHolder(v);
} else
return null;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
if (holder instanceof DataViewHolder) {
final DataViewHolder dataViewHolder = (DataViewHolder) holder;
final OrderListBaseModel.DataBean dataBean = getItem(position);
if (dataBean != null) {
dataViewHolder.setPosition(position);
dataViewHolder.setSingleBean(dataBean);
}
}
}
private OrderListBaseModel.DataBean getItem(int position) {
if (mList.size() > 0)
return mList.get(position);
else
return null;
}
public void showLoading(boolean status) {
showLoader = status;
}
@Override
public int getItemViewType(int position) {
if ((position == mList.size() - 1) && showLoader) {
return TYPE_FOOTER;
}
return TYPE_ITEM;
}
public void removeItem(int position) {
mList.remove(position);
notifyItemRemoved(position);
}
@Override
public int getItemCount() {
return mList.size();
}
public static class DataViewHolder extends RecyclerView.ViewHolder {
int position;
OrderListBaseModel.DataBean dataBean;
private TextView tv_row_po_no,textViewOptions;
public DataViewHolder(View v, final PurchaseOrderReceiveOnClick purchaseOrderReceiveOnClick) {
super(v);
tv_row_po_no = v.findViewById(R.id.tv_row_po_no);
textViewOptions = v.findViewById(R.id.textViewOptions);
}
public void setPosition(int position) {
this.position = position;
}
public void setSingleBean(OrderListBaseModel.DataBean dataBean) {
this.dataBean = dataBean;
}
}
private class FooterViewHolder extends RecyclerView.ViewHolder {
public FooterViewHolder(View view) {
super(view);
}
}
}
这是xml代码
loading_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/linearRoot"
android:gravity="center_horizontal"
android:layout_marginTop="@dimen/_5sdp">
<com.app.trackpoint.custom_loader.MYLoader
android:layout_width="@dimen/_30sdp"
app:my_color="@color/colorAccent"
android:layout_height="@dimen/_30sdp" />
</LinearLayout>