Android改造解析列表中的嵌套json响应

我正在创建一个基于新闻API的Android应用程序，它使用RecyclerView将特定频道的新闻（比如ABC新闻）加载到MainFragment中

我在MainFragment中对此进行API调用，如下所示：

MainFragment.java

public class MainFragment extends Fragment
{
   protected RecyclerView recyclerView;
   protected NewsAdapter adapter;
   protected String API_KEY;
   String sourceTitle, sourceID;
   List<Articles> articleList;

public MainFragment() {

}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState)
{
    ViewGroup root = (ViewGroup) inflater.inflate(R.layout.fragment_main, null);

    sourceTitle = "ABC News";
    sourceID = "abc-news";

    getActivity().setTitle(sourceTitle);

    API_KEY = getString(R.string.API_KEY);

    recyclerView = root.findViewById(R.id.recyclerview);

    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity().getApplicationContext());
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());

    ApiInterface apiService = ApiClient.getClient().create(ApiInterface.class);

    Call<News> call = apiService.getArticles(sourceID, API_KEY);

    call.enqueue(new Callback<News>()
    {
        @Override
        public void onResponse(Call<News> call, Response<News> response)
        {

            if (response != null && response.isSuccessful())
            {
                articleList = response.body().getArticles();
                populateRecycleView();
            }
            else
            {
                Toast.makeText(getActivity(), "Something went wrong..", Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onFailure(Call<News> call, Throwable t)
        {
            Toast.makeText(getActivity(), "Error in API Call", Toast.LENGTH_SHORT).show();
        }
    });

    recyclerView.addOnItemTouchListener(new RecyclerTouchListener(getActivity().getApplicationContext(), recyclerView, new ClickListener() {
        @Override
        public void onClick(View view, int position)
        {
            //onclick code
        }

        @Override
        public void onLongClick(View view, int position) {
        }
    }));
    return root;
}

     private void populateRecycleView()
     {
         if (articleList.isEmpty() || articleList.size() == 0)
         {
            recyclerView.setAdapter(null);
            Toast.makeText(getActivity(), "Error in List", Toast.LENGTH_SHORT).show();
         }
         else
         {
            adapter = new NewsAdapter(articleList, getActivity());
            recyclerView.setAdapter(adapter);
         }
    }

APIClient.java

 public class ApiClient
 {
  public static final String BASE_URL = "https://newsapi.org/v2/";
  private static Retrofit retrofit = null;


  public static Retrofit getClient()
  {
    if (retrofit==null)
    {
        retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .build();
    }
    return retrofit;
  }
 }

我无法理解在上述两个类中是否进行了正确的API调用，因为JSON数据没有在我的ArcTileList列表和数组适配器中得到解析

应用程序在API调用执行中崩溃

---

请注意：API调用正在工作。适配器正在成功加载API结果。

您需要了解的第一件事是，改型的方法是异步的。您的代码从上到下执行。平均时间

enqueue（）

方法启动对API的异步请求，如果成功，则将成功响应返回给

onResponse（）

方法，否则返回

onFailure（）

方法

那么，如何解决代码问题呢

首先需要为API响应创建POJO类（如果尚未创建），如下所示

Article.java

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Article {

    @SerializedName("source")
    @Expose
    private Source source;
    @SerializedName("author")
    @Expose
    private String author;
    @SerializedName("title")
    @Expose
    private String title;
    @SerializedName("description")
    @Expose
    private String description;
    @SerializedName("url")
    @Expose
    private String url;
    @SerializedName("urlToImage")
    @Expose
    private Object urlToImage;
    @SerializedName("publishedAt")
    @Expose
    private String publishedAt;
    @SerializedName("content")
    @Expose
    private String content;

    // constructors

    // getters and setter methods

    // use Alt + Insert to generate constructors, getter and setter methods in Android Studio

}

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Source {

    @SerializedName("id")
    @Expose
    private String id;
    @SerializedName("name")
    @Expose
    private String name;

    // constructors

    // getters and setter methods
}

import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class News {

    @SerializedName("status")
    @Expose
    private String status;
    @SerializedName("totalResults")
    @Expose
    private Integer totalResults;
    @SerializedName("articles")
    @Expose
    private List<Article> articles = null;

    // constructors

    // getters and setter methods
}

Source.java

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Article {

    @SerializedName("source")
    @Expose
    private Source source;
    @SerializedName("author")
    @Expose
    private String author;
    @SerializedName("title")
    @Expose
    private String title;
    @SerializedName("description")
    @Expose
    private String description;
    @SerializedName("url")
    @Expose
    private String url;
    @SerializedName("urlToImage")
    @Expose
    private Object urlToImage;
    @SerializedName("publishedAt")
    @Expose
    private String publishedAt;
    @SerializedName("content")
    @Expose
    private String content;

    // constructors

    // getters and setter methods

    // use Alt + Insert to generate constructors, getter and setter methods in Android Studio

}

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Source {

    @SerializedName("id")
    @Expose
    private String id;
    @SerializedName("name")
    @Expose
    private String name;

    // constructors

    // getters and setter methods
}

import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class News {

    @SerializedName("status")
    @Expose
    private String status;
    @SerializedName("totalResults")
    @Expose
    private Integer totalResults;
    @SerializedName("articles")
    @Expose
    private List<Article> articles = null;

    // constructors

    // getters and setter methods
}

News.java

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Article {

    @SerializedName("source")
    @Expose
    private Source source;
    @SerializedName("author")
    @Expose
    private String author;
    @SerializedName("title")
    @Expose
    private String title;
    @SerializedName("description")
    @Expose
    private String description;
    @SerializedName("url")
    @Expose
    private String url;
    @SerializedName("urlToImage")
    @Expose
    private Object urlToImage;
    @SerializedName("publishedAt")
    @Expose
    private String publishedAt;
    @SerializedName("content")
    @Expose
    private String content;

    // constructors

    // getters and setter methods

    // use Alt + Insert to generate constructors, getter and setter methods in Android Studio

}

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Source {

    @SerializedName("id")
    @Expose
    private String id;
    @SerializedName("name")
    @Expose
    private String name;

    // constructors

    // getters and setter methods
}

import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class News {

    @SerializedName("status")
    @Expose
    private String status;
    @SerializedName("totalResults")
    @Expose
    private Integer totalResults;
    @SerializedName("articles")
    @Expose
    private List<Article> articles = null;

    // constructors

    // getters and setter methods
}

通过这种方式，您可以很容易地发现在执行API请求时出错的地方

---

我在回答中跳过了你的部分代码，因为它是正确的，并且使我的回答有点长。请仔细查看我在回答中使用的方法名称和注释。

使用新闻列表<代码>呼叫@sajad是的，我已经纠正了我的错误。在API执行期间，arralist Articles列表仍然返回null检查internet权限，检查json的java模型（搜索json2pojo以获取帮助），检查onFailure中的可丢弃项