java - 无法在 Android 应用程序的对象内返回 JSON 对象

Question

所以我正在开发一个 Android 应用程序，它向服务器发出 API 调用并返回 JSON 信息。现在，在我的 Android 应用程序中，我可以解析 JSON，但只能解析到第一个数组。之后它说该类别不存在。

这是 JSON 响应布局:

    [
  {
    "success": 0,
    "error": "string",
    "response": {
      "lastseen": 0,
      "mapstats": {
        "maps": [
          {
            "tier": 0,
            "modeid": 0,
            "modename": "string",
            "modecolor": "string",
            "bonus": 0,
            "name": "string",
            "rank": 0,
            "time": "string",
            "num_completed": 0
          }
        ],
        "highest_tier": 0,
        "num_beaten": 0,
        "percent_completion": 0
      },
      "tag_color": "string",
      "name": "string",
      "rank": 0,
      "avatar": "string",
      "tag": "string",
      "playtime": 0,
      "percent": 0
    }
  }
]

这是我的 java 类:

package com.horizonservers.horizon;

import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Iterator;
import java.util.jar.Attributes;
import java.util.regex.Pattern;

import javax.net.ssl.HttpsURLConnection;


/**
 * A simple {@link Fragment} subclass.
 * Activities that contain this fragment must implement the
 * {@link MainFragment.OnFragmentInteractionListener} interface
 * to handle interaction events.
 * Use the {@link MainFragment#newInstance} factory method to
 * create an instance of this fragment.
 */
public class MainFragment extends Fragment {


    // TODO: Rename parameter arguments, choose names that match
    // the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    // TODO: Rename and change types of parameters
    private String mParam1;
    private String mParam2;
    private static final Pattern delimeter = Pattern.compile(",\\s+");

    private TextView mResult;

    private OnFragmentInteractionListener mListener;

    public MainFragment() {
        // Required empty public constructor
    }

    /**
     * Use this factory method to create a new instance of
     * this fragment using the provided parameters.
     *
     * @param param1 Parameter 1.
     * @param param2 Parameter 2.
     * @return A new instance of fragment MainFragment.
     */
    // TODO: Rename and change types and number of parameters
    public static MainFragment newInstance(String param1, String param2) {
        MainFragment fragment = new MainFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }

        new PostDataTask().execute("https://www.horizonservers.net/api/v1/PlayerInfo");


    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_main, container, false);
        mResult = (TextView) v.findViewById(R.id.tv_result);
        return v;
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }


    // TODO: Rename method, update argument and hook method into UI event
    public void onButtonPressed(Uri uri) {
        if (mListener != null) {
            mListener.onFragmentInteraction(uri);
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        if (context instanceof OnFragmentInteractionListener) {
            mListener = (OnFragmentInteractionListener) context;
        } else {
            throw new RuntimeException(context.toString()
                    + " must implement OnFragmentInteractionListener");
        }
    }

    @Override
    public void onDetach() {
        super.onDetach();
        mListener = null;
    }

    /**
     * This interface must be implemented by activities that contain this
     * fragment to allow an interaction in this fragment to be communicated
     * to the activity and potentially other fragments contained in that
     * activity.
     * <p>
     * See the Android Training lesson <a href=
     * "http://developer.android.com/training/basics/fragments/communicating.html"
     * >Communicating with Other Fragments</a> for more information.
     */
    public interface OnFragmentInteractionListener {
        // TODO: Update argument type and name
        void onFragmentInteraction(Uri uri);
    }

    class PostDataTask extends AsyncTask<String, Void, String> {

        ProgressDialog progressDialog;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

        }

        @Override
        protected String doInBackground(String... params) {

            try {
                return postData(params[0]);
            } catch (IOException ex) {
                return "Network error !";
            } catch (JSONException ex) {
                return "Data Invalid !";
            }
        }

        @Override
        protected void onPostExecute(String result) {

            try {
                JSONObject jsonObject = new JSONObject(result);

                String NameInfo = jsonObject.getString("name");

                JSONObject jsonObject1 = new JSONObject(NameInfo);

                for(int i = 0; i < jsonObject1.length(); i++){
                    JSONObject jsonPart = new JSONObject();

                    //Log.i("response", jsonPart.getString("response"));
                    String newName = jsonPart.getString("name");
                    //mResult.setText(NameInfo);
                    mResult.setText(newName);
                }


            } catch (JSONException e) {
                mResult.setText("Error!");
            }
            super.onPostExecute(result);


            if (progressDialog != null) {
                progressDialog.dismiss();
            }
        }


        private String postData(String urlPath) throws IOException, JSONException {

            StringBuilder result = new StringBuilder();
            BufferedWriter bufferedWriter = null;
            BufferedReader bufferedReader = null;

            try {
                //Create data to send to server
                JSONObject dataToSend = new JSONObject();
                dataToSend.put("apikey", "UPj07lqWdetOWrk9M8Ya9UZzeIAizjr4sYQRKzkHFYm1KaQDopytCFq9HHCerwNy");
                dataToSend.put("steamid", "STEAM_0:1:90345825");
                dataToSend.put("maptype", "surf");

                //Initialize and config request, then connect to server.


   URL url = new URL(urlPath);
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setReadTimeout(10000 /* milliseconds */);
            urlConnection.setConnectTimeout(10000 /* milliseconds */);
            urlConnection.setRequestMethod("POST");
            urlConnection.setDoOutput(true);  //enable output (body data)
            urlConnection.setRequestProperty("Content-Type", "application/json");// set header
            urlConnection.connect();

            //Write data into server
            OutputStream outputStream = urlConnection.getOutputStream();
            bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
            bufferedWriter.write(dataToSend.toString());
            bufferedWriter.flush();

            //Read data response from server
            InputStream inputStream = urlConnection.getInputStream();
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                result.append(line).append("&");
            }
        } finally {
            if (bufferedReader != null) {
                bufferedReader.close();
            }
            if (bufferedWriter != null) {
                bufferedWriter.close();
            }
        }

        return result.toString();

    }
}

}

将信息打印到屏幕的具体部分是

    @Override
    protected void onPostExecute(String result) {

        try {
            JSONObject jsonObject = new JSONObject(result);

            String NameInfo = jsonObject.getString("name");

            JSONObject jsonObject1 = new JSONObject(NameInfo);

            for(int i = 0; i < jsonObject1.length(); i++){
                JSONObject jsonPart = new JSONObject();

                //Log.i("response", jsonPart.getString("response"));
                String newName = jsonPart.getString("name");
                //mResult.setText(NameInfo);
                mResult.setText(newName);
            }


        } catch (JSONException e) {
            mResult.setText("Error!");
        }
        super.onPostExecute(result);


        if (progressDialog != null) {
            progressDialog.dismiss();
        }
    }

如何从数组/对象中解析这些对象。我已经尝试将其转换为数组，但此时情况变得更糟。预先感谢您的帮助。

Answer 1

我不确定您尝试从 JSON 响应中提取哪些数据。但我认为这个使用 Google Translate API 的示例会对您有所帮助。

JSON 响应:

"data": {
    "translations": [
        {
            "translatedText": "Hallo Welt",
            "detectedSourceLanguage": "en"
        }
    ]
}

如果我想获得翻译后的文本“Hallo Welt”，我会这样做:

public String parseJSONForTranslation(String jsonString) {
    try {
        JSONObject object = (JSONObject) new JSONTokener(jsonString).nextValue();
        return object.getJSONObject("data").getJSONArray("translations").
                getJSONObject(0).getString("translatedText");
    }
    catch (JSONException e) {
        return null;
    }
}

因此，如您所见，如果您想通过进入 JSON 响应的下一个“级别”来进一步提取信息，您可以使用 getJSONObject 或 getJSONArray (取决于它是否是数组)，直到到达“level”，您要提取的数据所在的位置。只有当你处于最后一个“级别”时，你才使用 getString 。希望这可以帮助您。