android - 无法解析 Twitter 趋势 JSON

Question

我正在寻求[博客]的帮助:http://www.androidhive.info/2012/01/android-json-parsing-tutorial/解析 twitter 趋势 JSON 文件，但它抛出 JSONException。下面是我的 Activity 代码

import java.util.ArrayList;

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

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;

public class TweeterJSONReader extends Activity {

    Button click;
    ListView resultList;
    EditText input;
    JSONAdapter myAdapter;
    ArrayList<SearchResult> mainList;
    JSONParser jParser;

    private String url ="https://api.twitter.com/1/trends/daily.json";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setLayout();

        jParser = new JSONParser();




    click.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    new JSONAsync().execute(url);
                }
            });
    }

    private class JSONAsync extends AsyncTask<String, Void, JSONObject>
    {

        JSONArray trends;
        @Override
        protected JSONObject doInBackground(String... params) {

            return jParser.getJSONFromUrl(params[0]);
        }

        @Override
        protected void onPostExecute(JSONObject result) {

            try{
                trends  = result.getJSONArray("trends");

                for(int i=0;i<trends.length();i++)
                {
                    JSONObject trend = trends.getJSONObject(i);
                    String name = trend.getString("name");
                    String query  = trend.getString("query");
                    SearchResult object  = new SearchResult(name, query);
                    mainList.add(object);
                    myAdapter  = new JSONAdapter(getApplicationContext(),R.layout.search_result_layout,mainList);
                    resultList.setAdapter(myAdapter);
                }
            }catch(JSONException ex)
            {
                ex.printStackTrace();
            }
        }

    }
    public void setLayout()
     {
         mainList = new ArrayList<SearchResult>();
         click = (Button) findViewById(R.id.display);
         resultList = (ListView) findViewById(R.id.resultList);

        input = (EditText) findViewById(R.id.editText1);

     }
}

我使用相同的方法通过哈希标签和用户名搜索推文，两者都工作正常，但是当我将它用于趋势时，它会抛出 JSONException以下是我得到的异常

04-04 12:09:25.919: W/ResponseProcessCookies(620): Invalid cookie header: "set-cookie: guest_id=v1%3A136505757287468464; Domain=.twitter.com; Path=/; Expires=Sat, 04-Apr-2015 06:39:32 UTC". Unable to parse expires attribute: Sat, 04-Apr-2015 06:39:32 UTC
04-04 12:09:25.950: W/System.err(620): org.json.JSONException: No value for trends
04-04 12:09:25.950: W/System.err(620):  at org.json.JSONObject.get(JSONObject.java:354)
04-04 12:09:25.950: W/System.err(620):  at org.json.JSONObject.getJSONArray(JSONObject.java:544)
04-04 12:09:25.969: W/System.err(620):  at com.zolipe.twitterapplication.TweeterJSONReader$JSONAsync.onPostExecute(TweeterJSONReader.java:63)
04-04 12:09:25.969: W/System.err(620):  at com.zolipe.twitterapplication.TweeterJSONReader$JSONAsync.onPostExecute(TweeterJSONReader.java:1)
04-04 12:09:25.969: W/System.err(620):  at android.os.AsyncTask.finish(AsyncTask.java:417)
04-04 12:09:25.969: W/System.err(620):  at android.os.AsyncTask.access$300(AsyncTask.java:127)
04-04 12:09:25.969: W/System.err(620):  at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
04-04 12:09:25.969: W/System.err(620):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 12:09:25.980: W/System.err(620):  at android.os.Looper.loop(Looper.java:123)
04-04 12:09:25.992: W/System.err(620):  at android.app.ActivityThread.main(ActivityThread.java:3683)
04-04 12:09:25.992: W/System.err(620):  at java.lang.reflect.Method.invokeNative(Native Method)
04-04 12:09:25.992: W/System.err(620):  at java.lang.reflect.Method.invoke(Method.java:507)
04-04 12:09:25.992: W/System.err(620):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-04 12:09:25.999: W/System.err(620):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-04 12:09:25.999: W/System.err(620):  at dalvik.system.NativeStart.main(Native Method)
04-04 12:09:28.470: D/dalvikvm(121): GC_EXPLICIT freed 126K, 49% free 3050K/5959K, external 3611K/4459K, paused 100ms

请帮帮我

以下是JSONParser的代码

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    public JSONObject getJSONFromUrl(String url) {

        // Making HTTP request
        try {
            // defaultHttpClient
            DefaultHttpClient httpClient = new DefaultHttpClient();
            HttpPost httpPost = new HttpPost(url);

            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            is = httpEntity.getContent();           

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

Answer 1

如果你去https://api.twitter.com/1/trends/daily.json ，你会看到 trends 实际上是一个 JSONObject，而不是 JSONArray。

将 trends 更改为 JSONObject 类型的对象，并更改此行:

trends  = result.getJSONArray("trends");

为此:

trends  = result.getJSONObject("trends");

此外，包含您正在寻找的所有趋势的 JSONArray 实际上包含在另一个以日期为键的 JSONObject 中，因此您需要添加这一步(在上述一步之后):

JSONArray trendArry = trends.getJSONArray("2013-04-03 08:20");