Question

我正在尝试使用volley解析json并在android的tabbed fragment类中使用recycleler-card视图进行显示。 json响应未显示在片段中。没有显示错误或异常。该应用程序运行正常，但没有显示数据。看看下面的代码，告诉我哪里出错了。

My Fragment Class

public class HomeFrag_RecyclerAdapter extends RecyclerView.Adapter<HomeFrag_RecyclerAdapter.MyHolder> {

private Context context;
List<NewsItems> newsItemsList;

public HomeFrag_RecyclerAdapter(Context context, List<NewsItems> newsItemsList) {
    this.context = context;
    this.newsItemsList = newsItemsList;
}

@Override
public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.tab_frags_customview,parent,false);
    return new MyHolder(v);
}

@Override
public void onBindViewHolder(MyHolder holder, int position) {
    holder.title.setText(newsItemsList.get(position).getNewTitle());
    holder.descn.setText(newsItemsList.get(position).getNewsDesc());
    holder.time.setText(newsItemsList.get(position).getNewsTime());
    holder.date.setText(newsItemsList.get(position).getNewsDate());

    int i = position;
    Picasso.with(context).load(newsItemsList.get(i).getImage_Id())
            .centerCrop()
            .error(R.drawable.ic_toc_black_24dp)
            .into(holder.coverImg);
}

@Override
public int getItemCount() {
    return newsItemsList.size();
}

public class MyHolder  extends RecyclerView.ViewHolder{

    private TextView title, descn, time, date;
    private ImageView coverImg;

    public MyHolder(View itemView) {
        super(itemView);

        title = (TextView) itemView.findViewById(R.id.news_titleTxt);
        descn = (TextView) itemView.findViewById(R.id.news_DescTxt);
        time = (TextView) itemView.findViewById(R.id.news_TimeTxt);
        date = (TextView) itemView.findViewById(R.id.newsDateTxt);

        coverImg = (ImageView) itemView.findViewById(R.id.newsImage);

    }
}
}

片段适配器代码如下所示：

<pre>
{
  "0": {
    "image": null,
    "title": "Suresh Raina to miss 2nd ODI against New Zealand ",
    "time": "08:29 pm ",
    "date": "18 Oct ",
    "content": "Indian cricketer Suresh Raina will miss the second ODI against New Zealand at Delhi on Thursday. ...",
    "link": "https://full-story.newsinshorts.com/v1/article/a659a7be-0c4d-408c-851d-689da6b95498-1 "
  },
  "1": {
    "image": null,
    "title": "Harley-Davidson net income falls by 18.67% to $114 mn ",
    "time": "08:29 pm ",
    "date": "18 Oct ",
    "content": "Motorcycle manufacturer Harley-Davidson on Tuesday reported an 18.67% year-on-year decline in net ...",
    "link": "https://full-story.newsinshorts.com/v1/article/448cc170-1d42-4109-9c50-0fe3a3c36f44-1 "
  },
  "2": {
    "image": null,
    "title": "JNU to get 200 solar power operated street lights ",
    "time": "08:27 pm ",
    "date": "18 Oct ",
    "content": "The Jawaharlal Nehru University in Delhi is set to get 200 solar power operated street lights, Vice ...",
    "link": "https://full-story.newsinshorts.com/v1/article/96db26c8-be8f-4313-8d51-27fee9bd084d-1 "
  },
  "3": {
    "image": null,
    "title": "Patiala Court dismisses fake degree case against Irani ",
    "time": "08:22 pm ",
    "date": "18 Oct ",
    "content": "Patiala House Court today dismissed a case against Union Minister Smriti Irani for allegedly ...",
    "link": null
  },
</pre>

要解析的示例JSON

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.joey.mydrawerapp.Fragments.HomeFragment_Fragments.Latest_News">

<!-- TODO: Update blank fragment layout -->

<include layout="@layout/recyclerview_layout"
    android:id="@+id/latestNews_recyclerView"/>

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:textSize="30sp"
    android:gravity="center"
    android:textStyle="bold"
    android:text="Stay Tuned For Latest News" />

</RelativeLayout>

上面的Fragment类的XML布局：

$request->input('input_file')

Answer 1

我通常不再手工解析JSON，我总是使用Gson或jackson。如果你的json是正确的，你的onResponse可能看起来像这样：

StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
          new Response.Listener<String>() {
              @Override
              public void onResponse(String response)
   @Override
   public void onResponse(Stringresponse) {

         Gson gson = new Gson();
         Map<String,Item> map = gson.fromJson(response, new TypeToken<Map<String,Item>>(){}.getType());

         newsItemLists = new ArrayList();   // Clear the list if desired

         for (Item item : map.values()) {
            newsItems = new NewsItems();
             // Copy all item attributes to newsItems here.
             // if NewsItems is annotated correct, it can even be used to parse
             // the json instead of the Item class below.
            newsItemsList.add(newsItems);            
         }

      // Move this line into the onCreate() initializng the adapter with an empty list.
      //recyclerView.setAdapter(new HomeFrag_RecyclerAdapter(getActivity(), newsItemsList));
      // add this to notify the adapter that the list has changed.
      adapter.notifyDataSetChanged();
   }

你需要为gson对象添加一个pojo：

 class Item {
      String image;
      String title;
      String time;
      String date;
      String content;
      String link;
   }

<强>更新

我已经更新了我的答案，以便制作StringRequest排球而不是JSONRequest。我们将使用整个字符串响应并将其解析为JSON。或者，您可以将您的Volley JsonObjectRequest更改为JsonArrayRequest并接收JSON数组。然后，您将循环遍历数组中的每个项目并将其解析出来。

JSON解析并显示到回收卡视图片段中

1 个答案: