使用片段中的 Asynctask 将 json 解析为 recyclerview

Question

想在片段中使用 Asynctask 解析 json 到 recyclerview，但是当午餐应用程序时，应用程序崩溃了！

这是我的 json 数据：

{
    "contacts": [
        {
                "id": "c200",
                "name": "erfan",
                "email": "erfan@gmail.com",
                "address": "xx-xx-xxxx,x - street, x - country",
                "gender" : "male",
                "phone": {
                    "mobile": "+91 0000000000",
                    "home": "00 000000",
                    "office": "00 000000"
                }
        },
        {
                "id": "c201",
                "name": "Johnny Depp",
                "email": "johnny_depp@gmail.com",
                "address": "xx-xx-xxxx,x - street, x - country",
                "gender" : "male",
                "phone": {
                    "mobile": "+91 0000000000",
                    "home": "00 000000",
                    "office": "00 000000"
                }
        }

  ]
}

想要获取姓名、电子邮件、手机

这是我的片段：

public class maghalat extends Fragment {

    private RecyclerView recyclerView;
    private DataAdapter adapter;
    private View myFragmentView;

    private String TAG = MainActivity.class.getSimpleName();
    private ProgressDialog pDialog;
    // URL to get contacts JSON
    private static String url = "http://memaraneha.ir/Erfan/jsonravi.php";

    List<jsonContent> listcontent=new ArrayList<>();
    public jsonContent content;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        myFragmentView = inflater.inflate(R.layout.maghalat, container, false);

          new GetContacts().execute();

        return myFragmentView;
    }

            class GetContacts extends AsyncTask<Void, Void, Void> {

                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    // Showing progress dialog
                    pDialog = new ProgressDialog(getActivity());
                    pDialog.setMessage("Please wait...");
                    pDialog.setCancelable(false);
                    pDialog.show();

                }

                @Override
                protected Void doInBackground(Void... arg0) {
                    HttpHandler sh = new HttpHandler();

                    // Making a request to url and getting response
                    String jsonStr = sh.makeServiceCall(url);

                    Log.e(TAG, "Response from url: " + jsonStr);

                    if (jsonStr != null) {
                        try {
                            JSONObject jsonObj = new JSONObject(jsonStr);

                            // Getting JSON Array node
                            JSONArray contacts = jsonObj.getJSONArray("contacts");

                            // looping through All Contacts
                            for (int i = 0; i < contacts.length(); i++) {
                                JSONObject c = contacts.getJSONObject(i);

                                content.name=c.getString("name");
                                content.email=c.getString("email");

                                JSONObject phone = c.getJSONObject("phone");
                                content.mobile=phone.getString("mobile");

                                listcontent.add(content);
                            }
                        } catch (final JSONException e) {
                            Log.e(TAG, "Json parsing error: " + e.getMessage());
                            getActivity().runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    Toast.makeText(getActivity().getApplicationContext(),
                                            "Json parsing error: " + e.getMessage(),
                                            Toast.LENGTH_LONG)
                                            .show();
                                }
                            });

                        }
                    } else {
                        Log.e(TAG, "Couldn't get json from server.");
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                Toast.makeText(getActivity().getApplicationContext(),
                                        "Couldn't get json from server. Check LogCat for possible errors!",
                                        Toast.LENGTH_LONG)
                                        .show();
                            }
                        });

                    }

                    return null;
                }

                @Override
                protected void onPostExecute(Void result) {
                    super.onPostExecute(result);

                    pDialog.dismiss();
                    /**
                     * Updating parsed JSON data into ListView
                     * */

                    recyclerView=(RecyclerView)myFragmentView.findViewById(R.id.recycler_view);
                    recyclerView.setHasFixedSize(true);
                    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity().getApplicationContext());
                    recyclerView.setLayoutManager(layoutManager);
                    adapter=new DataAdapter(getActivity(),listcontent);
                    recyclerView.setAdapter(adapter);
                }

            }}

这是我的 HttpHandler：

public class HttpHandler {

    private static final String TAG = HttpHandler.class.getSimpleName();

    public HttpHandler() {
    }

    public String makeServiceCall(String reqUrl) {
        String response = null;
        try {
            URL url = new URL(reqUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            // read the response
            InputStream in = new BufferedInputStream(conn.getInputStream());
            response = convertStreamToString(in);
        } catch (MalformedURLException e) {
            Log.e(TAG, "MalformedURLException: " + e.getMessage());
        } catch (ProtocolException e) {
            Log.e(TAG, "ProtocolException: " + e.getMessage());
        } catch (IOException e) {
            Log.e(TAG, "IOException: " + e.getMessage());
        } catch (Exception e) {
            Log.e(TAG, "Exception: " + e.getMessage());
        }
        return response;
    }

    private String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line).append('\n');
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

这是我的 recyclerview 适配器：

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {
    private Context context;
    List<jsonContent> jcontent;



    public DataAdapter(Context context,List<jsonContent> jcontent) {

        this.context=context;
        this.jcontent=jcontent;
    }



    @Override
    public DataAdapter.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.card_row, viewGroup, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(DataAdapter.ViewHolder viewHolder,int i) {



        viewHolder.name.setText(jcontent.get(i).name);
        viewHolder.email.setText(jcontent.get(i).email);
        viewHolder.mobile.setText(jcontent.get(i).mobile);


    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{
        private TextView name,email,mobile;



        public ViewHolder(final View view) {
            super(view);


            name = (TextView)view.findViewById(R.id.name);
            email = (TextView)view.findViewById(R.id.email);
            mobile = (TextView)view.findViewById(R.id.mobile);




        }
    }
}

这是json内容class：

public class jsonContent {

    public String name;
    public String email;
    public String mobile;

}

所以我哪里错了？请帮忙

Answer 1

您在未创建对象的情况下在 jsonContent 内容中赋值。你应该在 AsyncTask

的 doinBackGround() 中这样做

jsonContent content=new jsonContent();
content.name=c.getString("name");
content.email=c.getString("email");

content.mobile=phone.getString("mobile");

使用片段中的 Asynctask 将 json 解析为 recyclerview

parsing json to recyclerview with Asynctask in fragment

android

android-asynctask

android-fragments

android-json

android-recyclerview