Question

我正在尝试使用Volley在Fragment中使用GSON解析JSON。但我在两个地方得到编译时错误

new Response.Listener<String>：说听众无法解决
new Response.ErrorListener()：说无法解析ErrorListener

无法解析方法“fromJson”

public class Gson extends Fragment 
{

    RecyclerView recyclerView;
    Response responseobj;
    CustomAdapter customAdapter;
    String url = "https://newsapi.org/v1/articles?source=techcrunch&apiKey=ed28d2d13805495a9b896ecb0c7b6ed1";
    Gson gson;
    RequestQueue requestQueue;

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

        View view = inflater.inflate(R.layout.gson, container, false);

        recyclerView = (RecyclerView) view.findViewById(R.id.movielist);

        requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());

        StringRequest stringRequest = new StringRequest( com.android.volley.Request.Method.GET, url, new Response.Listener<String>() 
        {
                    @Override
                    public void onResponse(String response) 
                    {
                        // Do something with the response

                        gson = new Gson();
                        responseobj = gson.fromJson(response, Response.class);
                        customAdapter = new CustomAdapter(getActivity().getApplicationContext(), responseobj.getArticles());
                        recyclerView.setAdapter(customAdapter);

                    }
                },
                new Response.ErrorListener() 
                {
                    @Override
                    public void onErrorResponse(VolleyError error) 
                    {
                        // Handle error
                    }
         });

        //returning our layout file
        //change R.layout.yourlayoutfilename for each of your fragments
        requestQueue.add(stringRequest);
        return view;

    }


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) 
    {
        super.onViewCreated(view, savedInstanceState);
        //you can set the title for your toolbar here for different fragments different titles
        getActivity().setTitle("GSON Parsing");
    }
}

Answer 1

我认为问题出在你的Response类中，根据你的链接应该是这样的：

public class FragmentGson extends Fragment

其次更改您的片段名称（可能是您导入错误）

 - src [Folder] 
   - content [Folder]
     - migrations [Folder]
     - __init__.py
     - admin.py
     - apps.py
     - models.py
     - tests.py
     - views.py
  - main [Folder]
     - settings [Folder]
         - __init__.py
         - base.py
     - migrations [Folder]
     - __init__.py
     - db.sqlite3
     - models.py
     - urls.py
     - views.py
     - wsgi.py
  - posts [Folder]
     - migrations [Folder]
     - templatetags [Folder]
     - __init__.py
     - admin.py
     - apps.py
     - forms.py
     - models.py
     - tests.py
     - urls.py
     - utils.py
     - views.py
    - templates
     - base.html
     - blogbase.html

Answer 2

如果您收到无法解析Reponse.listener的消息，可能是因为它未知。您是否正确添加了像compile 'com.android.volley:volley:1.0.0'这样的Volley依赖项并在Fragment中正确导入了Volley？

Answer 3

从您粘贴的代码中，我发现Response responseobj指的是您在片段中创建并导入的Response类。与此同时，您正在使用new Response.Listener<>()，它应该是排球库中Response类的实例。现在如果未导入凌空的Response，它将显示错误。

这意味着您还必须从排球中导入Response课程。确保你已经添加了这两个导入。

import com.android.volley.Response;

第二件事是，您必须将片段名称从Gson更改为其他内容。否则会引起问题

GSON在片段中使用Volley - 错误

3 个答案: