錯誤JSONArray無法轉換爲JSONObject

Question

我創建了一個應用程序來解析JSON數據從服務器到我的應用程序。但是現在當我運行項目時，我得到的JSONArray無法轉換爲JSONObject exception.I在我的LogCat視圖中獲取所有服務器數據，但在應用程序中沒有。我嘗試了不同的方法，但沒有運氣。 謝謝。

//這是我的主要代碼

public class jsonExample2 extends Activity{ 
      // This is the url that i try to get data 
     private static String url = "http://api.worldbank.org/countries/ir?format=json"; 
     private static final String PAGE = "page"; 
     private static final String VALUE = "value"; 
     private static final String NAME = "name"; 
     private static final String GEO = "region"; 

     JSONArray page = null; 
      @Override 
      protected void onCreate(Bundle savedInstanceState) { 

       super.onCreate(savedInstanceState); 
       setContentView(R.layout.activitybw); 
       new GetJSONTask().execute(url); 

      } 

      class GetJSONTask extends AsyncTask<String, Void, JSONObject> { 

       protected JSONObject doInBackground(String... urls) { 
        try { 
         JSONParser jParser = new JSONParser(); 
         return jParser.getJSONFromUrl(urls[0]); 
        } catch (Exception e) { 
         return null; 
        } 
       } 

       protected void onPostExecute(JSONObject json) { 
        // do all the parsing here: 
        try { 

         page = json.getJSONArray(PAGE); 
         JSONObject c = page.getJSONObject(0); 


         String value = c.getString(VALUE); 
         String name = c.getString(NAME); 
         String geo = c.getString(GEO); 

         final TextView id1 = (TextView) findViewById(R.id.id); 
         final TextView name1 = (TextView) findViewById(R.id.name); 
         final TextView geo1 = (TextView) findViewById(R.id.geo); 

         id1.setText(value); 
         name1.setText(name); 
         geo1.setText(geo); 
        } 
        catch (JSONException e) 
        { 
         e.printStackTrace(); 
        } 
       } 
      }   
    } 

// JSONParser類

public class JSONParser { 

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

     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 { 
       jObj = new JSONObject(json); 
      } catch (JSONException e) { 
       Log.e("JSON Parser", "Error parsing data " + e.toString()); 
      } 
      return jObj; 
     } 

    } 

//這是我的看法logcat中

03-19 09:11:52.776: D/dalvikvm(1376): GC_CONCURRENT freed 129K, 10% free 2629K/2904K, paused 75ms+101ms, total 286ms 
    03-19 09:11:52.846: E/JSON Parser(1376): Error parsing data org.json.JSONException: Value [{"total":1,"page":1,"per_page":"50","pages":1},[{"region":{"value":"Middle East & North Africa (all income levels)","id":"MEA"},"id":"IRN","incomeLevel":{"value":"Upper middle income","id":"UMC"},"name":"Iran, Islamic Rep.","iso2Code":"IR","lendingType":{"value":"IBRD","id":"IBD"},"longitude":"51.4447","latitude":"35.6878","capitalCity":"Tehran","adminregion":{"value":"Middle East & North Africa (developing only)","id":"MNA"}}]] of type org.json.JSONArray cannot be converted to JSONObject 
    03-19 09:11:52.846: D/AndroidRuntime(1376): Shutting down VM 
    03-19 09:11:52.855: W/dalvikvm(1376): threadid=1: thread exiting with uncaught exception (group=0x40a71930) 
    03-19 09:11:52.876: E/AndroidRuntime(1376): FATAL EXCEPTION: main 
    03-19 09:11:52.876: E/AndroidRuntime(1376): java.lang.NullPointerException 
    03-19 09:11:52.876: E/AndroidRuntime(1376):  at com.example.mediaplayerapp.jsonExample2$GetJSONTask.onPostExecute(jsonExample2.java:79) 

Answer 1

try { 
    jObj = new JSONObject(json); 
    } catch (JSONException e) { 
    Log.e("JSON Parser", "Error parsing data " + e.toString()); 
    } 

這是錯誤的。您正在獲得JSONArray，但您將其轉換爲JSONObject。將其更改爲

try { 
    if (json != null) 
     return new JSONArray(json); 
    } catch (JSONException e) { 
    Log.e("JSON Parser", "Error parsing data " + e.toString()); 
    }