從Java檢索JSONArray（Android）

我試圖解析從PHP接收到的JSONArray。我從我的日誌貓看到，我得到的值是[[「84.0918544152744」]，[「84.0918544152744」]]，但是當我去解析數組中的元素時，我得到一個NullPointerException。這裏是我的代碼：從Java檢索JSONArray（Android）

private class SetAverages extends AsyncTask<Void, Void, BufferedReader> { 
     @Override 
     protected BufferedReader doInBackground(Void... params) { 
      String url = "..."; 

      Log.i(LOG_TAG, "URL = " + url); 
      URL iuri; 
      try { 
       iuri = new URL(url); 
       URLConnection connection = iuri.openConnection(); 
       connection.setDoInput(true); 
       connection.setDoOutput(true); 
       connection.setUseCaches(false); 
       connection.setRequestProperty("Content-type", 
         "application/x-www-form-urlencoded"); 
       BufferedReader br = new BufferedReader(new InputStreamReader(
         (InputStream) connection.getContent())); 
       Log.i(LOG_TAG, "br value is " + br.readLine()); 
       return br; 
      } catch (MalformedURLException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
      return null; 
     } 

     @Override 
     protected void onPostExecute(BufferedReader br) { 
      if(br == null){ 
       Log.v(LOG_TAG, "br from set averages is null"); 
       return; 
      } 

      Log.v(LOG_TAG, "Get Averages onPostExecute"); 
      try{ 

       Log.i(LOG_TAG, "br value is " + br.toString()); 
       Log.i(LOG_TAG, "about to set up json array...."); 

       JSONObject inputjson = new JSONObject(br.readLine()); 
       //JSONArray inputjson = new JSONArray(br.readLine()); 
       Log.i(LOG_TAG, "this worked...."); 

       Log.i(LOG_TAG, "size of inputjson = " + inputjson.length()); 
       return; 
      }catch(NullPointerException e){ 
       Log.e(LOG_TAG, "Unable to get averages, NullPointerException"); 
       e.printStackTrace(); 
      }catch(NumberFormatException e){ 
       Log.e(LOG_TAG, "Unable to get averages, Number Format Exception"); 
       e.printStackTrace(); 
      } catch (JSONException e) { 
       Log.e(LOG_TAG, "JSON Exception"); 
       e.printStackTrace(); 
      } catch (IOException e) { 
       Log.e(LOG_TAG, "IO Exception"); 
       e.printStackTrace(); 
      } 

      return; 
     }

這裏是logcat的摘錄：

12-22 20:07:59.345: INFO/HA(1000): br value is [["84.0158352941176"],["84.0158352941176"]] 
12-22 20:07:59.355: VERBOSE/HA(1000): Get Averages onPostExecute 
12-22 20:07:59.355: INFO/HA(1000): br value is [email protected] 
12-22 20:07:59.355: INFO/HA(1000): about to set up json array.... 
12-22 20:07:59.355: ERROR/HA(1000): Unable to get averages, NullPointerException

來源

2011-12-23 Johanne Smith

爲什麼使用br.readLine創建對象？ – gwa 2011-12-23 01:34:34

br.readline發送一個應該能夠格式化爲JSON數組或JSON對象的數組。將這個數組傳遞給對象本身應該是正確的？我可能會誤解。 – 2011-12-23 01:43:12

的BufferedReader BR =新BufferedRe .. Log.i（LOG_TAG，「BR值是」 + br.readLine（））;

在這裏，你所走的線路緩衝，所以當你來到這裏：

   JSONObject inputjson = new JSONObject(br.readLine());

你不再有一個字符串。

嘗試刪除此行Log.i（LOG_TAG，「br value is」+ br.readLine（））;

祝你好運！

來源

2011-12-23 02:19:41 ademar111190

這是問題所在。謝謝！我不知道這是真的。 – 2011-12-23 12:31:03

從Java檢索JSONArray（Android）

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