Android 分页库中的 loadAfter() 从 API 无限加载第一页

Question

I'm implementing the paging library 2.1.2 in my Android app, my DataSource class looks like this

public class TransactionsDataSource extends PageKeyedDataSource<Integer, Items> {


private static final int FIRST_PAGE = 1;
private Context context;
private Repository repository;
private String bearerToken;
private int merchantId;


public TransactionsDataSource(Context context, int merchantId) {
    this.context = context;
    this.merchantId = merchantId;
    repository = new Repository();
    repository.initLoginSharedPref(context);
    bearerToken = repository.getAccessToken();
}


@Override
public void loadInitial(@NonNull PageKeyedDataSource.LoadInitialParams<Integer> params, @NonNull PageKeyedDataSource.LoadInitialCallback<Integer, Items> callback) {


    ApiClient.getApiClient().getApiInterface().getMerchantTransactions(bearerToken,
            merchantId, FIRST_PAGE)
            .enqueue(new Callback<MainResponse>() {
                @Override
                public void onResponse(Call<MainResponse> call, Response<MainResponse> response) {
                    if (response.body() != null){

                        int code = response.body().getCode();
                        if (code == SERVER_OK_CODE){
                            callback.onResult(response.body().getData().getItems(), null, FIRST_PAGE + 1);
                        } else if (code == SERVER_UNAUTHENTICATED_CODE){

                            repository.clearCache();
                            HelperMethods.signOut(context);
                        } else {
                            //no more data to load
                        }


                    }
                }

                @Override
                public void onFailure(Call<MainResponse> call, Throwable t) {

                }
            });
}

@Override
public void loadBefore(@NonNull PageKeyedDataSource.LoadParams<Integer> params, @NonNull PageKeyedDataSource.LoadCallback<Integer, Items> callback) {

}

@Override
public void loadAfter(@NonNull PageKeyedDataSource.LoadParams<Integer> params, @NonNull PageKeyedDataSource.LoadCallback<Integer, Items> callback) {


    ApiClient.getApiClient().getApiInterface().getMerchantTransactions(bearerToken,
            merchantId, params.key)
            .enqueue(new Callback<MainResponse>() {
                @Override
                public void onResponse(Call<MainResponse> call, Response<MainResponse> response) {
                    if (response.body() != null){

                        int code = response.body().getCode();
                        if (code == SERVER_OK_CODE){

                            Integer key = params.key + 1;
                            callback.onResult(response.body().getData().getItems(), key);

                        } else if (code == SERVER_UNAUTHENTICATED_CODE){

                            repository.clearCache();
                            HelperMethods.signOut(context);
                        } else {
                            //no more data to load
                        }

                    }
                }

                @Override
                public void onFailure(Call<MainResponse> call, Throwable t) {

                }
            });
}

}

As per my knowledge the loadInitial() method is reponsible for loading the first page of data and then loadAfter() will be triggered after that to load the rest of the pages while the key is incremented by one until there's no more data to be loaded. But when I debug the app the loadAfter() is continously repeat loading the first page only even I make sure to increment the params.key() by 1. I even tried to hard code the page number as following but still loading the first page only

ApiClient.getApiClient().getApiInterface().getMerchantTransactions(bearerToken,
        merchantId, 2)

I need to know what's happening and how to fix this bug?

Answer 1

Although my implementation is 100% correct and After I tried so many things finally I got my way to solve this weird behavior. I made a small change in my interface instead of passing the page number to getMerchantTransactions() I decided to send the whole url as a parameter and it worked fine here's my method in interface after update

@POST
@FormUrlEncoded
Call<MainResponse> getMerchantTransactions(@Header("Authorization") String bearerToken,
                                           @Field("id") int merchantId,
                                           @Url String url);

And then calling this method in loadInitial() and loadAfter() like this

ApiClient.getApiClient().getApiInterface().getMerchantTransactions(bearerToken,
            merchantId, "myUrl?pagenumber=" + params.key)