Android GET 改造失败 API 调用服务器

Question

我正在做一个 Android 项目。我正在使用改造来调用 API。所以我正在调用 API 来获取与证书关联的课程列表。

从服务器获取 (BASE_URL/certificates/1) 的响应是：

{
  "id": 1,
  "name": "Arts-certificate",
  "authorized_by": "priya",
  "created_by": "self",
  "created_by_id": "1",
  "description": "awarded to the best",
  "doc_url": "http://f8rentals.com/wp-content/uploads/2015/03/IMG_0067ft.jpg?189db0",
  "category_id": "2",
  "cateogory": "Arts",
  "courses": [
    {
      "id": 1,
      "course_id": "CRSXQHGZ0SCTLhklhk6JL",
      "number_of_sessions": 1,
      "created_at": "2015-12-16T07:10:37.000+00:00",
      "updated_at": "2015-12-16T07:10:37.000+00:00",
      "tags": null
    },
    {
      "id": 1,
      "course_id": "CRSXQHGZ0SCTLhklhk6JL",
      "number_of_sessions": 1,
      "created_at": "2015-12-16T07:10:37.000+00:00",
      "updated_at": "2015-12-16T07:10:37.000+00:00",
      "tags": null
    }
    .
    .
    .
    .
  ]
}

我有证书列表，需要执行的操作是，单击证书后，它应该转到新片段，其中包含与该证书相关联的所有课程（单击该片段）。为此，我进行了上述 API 调用。

问题是当我单击列表中的第一个证书时它会转到下一个片段并列出所有课程。但是当我单击任何其他证书时，它会显示空白片段。当我调试代码时，在 fetchCourses() CoursesListOfCertificatesFragment.java 中调用了 onFailure() 函数。

Workflow 是 CertificateFragment 是 class，其中列出了所有证书。单击时，CertificateFragment 中的 CertificateClickListner() 被触发，然后启动 CoursesListOfCertificatesFragment，并在该片段的构造函数中传递证书对象。在这里，我使 API 调用 GET (BASE_URL/certificates/1)。

这是在 CoursesListOfCertificatesFragment 中的 fetchCourses() 中。但是除了第一个证书，调用了 onFailure() 方法。

感谢任何帮助.....如果需要任何其他信息，请询问。

谢谢。

下面列出了相关的 class：

CoursesListOfCertificatesFragment.java

package com.localjini.learner.fragments;

import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ProgressBar;
import android.widget.TextView;

import com.localjini.learner.R;
import com.localjini.learner.adapters.CourseListingRVAdapter;
import com.localjini.learner.api.RestClient;
import com.localjini.learner.main.HomeActivity;
import com.localjini.learner.models.Certificates;
import com.localjini.learner.models.Course;
import com.localjini.learner.models.CoursesResponse;
import com.localjini.learner.models.GetCertificateResponse;
import com.localjini.learner.utils.LogUtils;
import com.localjini.learner.utils.UIHelper;

import java.util.List;

import butterknife.Bind;
import butterknife.ButterKnife;
import retrofit.Call;
import retrofit.Callback;
import retrofit.Response;
import retrofit.Retrofit;


public class CoursesListOfCertificatesFragment extends BaseFragment {

    @Bind(R.id.tv_category)
    TextView tvCategory;
    @Bind(R.id.tv_sort_filter)
    TextView tvSortFilter;
    @Bind(R.id.pb_course_listing)
    ProgressBar pbCourseListing;
    @Bind(R.id.rv_course_listing)
    RecyclerView rvCourseListing;

    public UIHelper uiHelper;
    List<Course> courses;

    private Certificates certificate;
    private int certificate_id;

    public CoursesListOfCertificatesFragment(){

    }

    private CourseListingRVAdapter.CourseClickListener listener = new CourseListingRVAdapter.CourseClickListener() {

        @Override
        public void onCourseClicked(Course course) {
            interactionListener.launchCourseDetailFragment();
        }
    };

    public CoursesListOfCertificatesFragment(Certificates certificate){
        this.certificate = certificate;
        this.certificate_id = certificate.getId();
    }

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        if (root == null) {
            root = (ViewGroup) inflater.inflate(R.layout.fragment_course_listing, container, false);

            ButterKnife.bind(this, root);

            initInstances();

            fetchCourses();
        }


        return root;
    }

    private void initInstances() {
        uiHelper = new UIHelper(getActivity());

        ((HomeActivity) getActivity()).getSupportActionBar().setHomeButtonEnabled(true);
        ((HomeActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        ((HomeActivity) getActivity()).getSupportActionBar().setTitle("");

        rvCourseListing.setItemAnimator(new DefaultItemAnimator());
        rvCourseListing.setLayoutManager(new LinearLayoutManager(getActivity()));
        rvCourseListing.setHasFixedSize(true);
    }

    private void fetchCourses() {
        Call<GetCertificateResponse> call = RestClient.getCMSServiceInstance().getCertificateById(certificate_id);
        call.enqueue(new Callback<GetCertificateResponse>() {
            @Override
            public void onResponse(Response<GetCertificateResponse> response, Retrofit retrofit) {

                if (response != null) {
                    GetCertificateResponse resp = response.body();

                    if (resp != null) {
                        showCourses(resp.getCourses());
                    } else {
                        uiHelper.showToast("response contain null data");
                    }
                }
            }

            @Override
            public void onFailure(Throwable t) {
                LogUtils.d("coursesFailed", t.getMessage());
            }
        });

    }

    private void showCourses(List<Course> courses) {
        if(courses != null) {
            CourseListingRVAdapter courseListingRVAdapter = new CourseListingRVAdapter(getActivity(), courses);
            courseListingRVAdapter.setCourseClickListener(listener);
            rvCourseListing.setAdapter(courseListingRVAdapter);
        }
    }

    public FragmentId getFragmentId() {
        return FragmentId.COURSE_LISTING_FRAGMENT;
    }

}

CertificateFragment.java

public class CertificateFragment extends BaseFragment {

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";
    //protected ViewGroup root;
    protected Context context;
    @Bind(R.id.rv_Certificates) RecyclerView rvCertificates;

    private CertificateRVAdapter.CertificateClickListener listener = new CertificateRVAdapter.CertificateClickListener() {

        @Override
        public void onCertificateClicked(Certificates certificate) {
            Toast.makeText(getActivity(), certificate.getName() +" Clicked", Toast.LENGTH_SHORT).show();
            //interactionListener.launchCourseListingFragment();
            interactionListener.launchCoursesListOfCertificatesFragment(certificate);
        }
    };


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        if(root==null) {

            root = (ViewGroup) inflater.inflate(R.layout.fragment_certificate, container, false);
            ButterKnife.bind(this, root);

            initInstances();
            getCertificates();
        }
        return root;
    }
//    rvCourseListing.setItemAnimator(new DefaultItemAnimator());
//    rvCourseListing.setLayoutManager(new LinearLayoutManager(getActivity()));
//    rvCourseListing.setHasFixedSize(true);
//

    private void initInstances() {
        //uiHelper = new UIHelper(getActivity());

        ((HomeActivity) getActivity()).getSupportActionBar().setHomeButtonEnabled(true);
        ((HomeActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        ((HomeActivity) getActivity()).getSupportActionBar().setTitle("");

        rvCertificates.setItemAnimator(new DefaultItemAnimator());
        rvCertificates.setLayoutManager(new LinearLayoutManager(getActivity()));
        rvCertificates.setHasFixedSize(true);
    }

    private void getCertificates() {

        Call<AllCertificateResponse> call = RestClient.getCMSServiceInstance().getCertificates();

        call.enqueue(new Callback<AllCertificateResponse>() {
            @Override
            public void onResponse(Response<AllCertificateResponse> response, Retrofit retrofit) {
                if (response.isSuccess()) {
                    //com.squareup.okhttp.Response raw = response.body().raw();

                    List<Certificates> certificates = response.body().getCertificates();
                    if (certificates != null)
                        showCertificates(certificates);

                    Toast.makeText(getActivity(), "Success in getting certificates", Toast.LENGTH_SHORT).show();
                } else {
                    Log.d("CERT", "response is failure");
                }
            }

            @Override
            public void onFailure(Throwable t) {
                Toast.makeText(getActivity(), "Failure", Toast.LENGTH_SHORT).show();
            }

        });
    }

    public void showCertificates(List<Certificates> certificates){

        CertificateRVAdapter adapter = new CertificateRVAdapter(getActivity(), certificates);
        adapter.setCertificateClickListener(listener);
        rvCertificates.setAdapter(adapter);
    }

    public FragmentId getFragmentId() {
        return FragmentId.COURSE_LISTING_FRAGMENT;
    }

}

Answer 1

我解决了这个问题。原来服务器给出了错误的响应（它仍处于测试阶段）。我期待字符串数组。虽然对于第一个证书，所有课程都有字符串数组，但对于第二个证书，所有课程都有字符串值而不是数组。

Android GET 改造失败 API 调用服务器

Android failed GET retrofit API call to server

java

android

android-fragments

retrofit