JSON解析错误 - 字符串无法转换为JSONArray

Question

我在运行我的Android应用程序时遇到问题。这是一个简单的活动，旨在通过HTTP从远程数据库获取数据。

我得到的日志猫这两个错误：

错误解析成JSON的getJarrayFromString（）; org.json.JSONException：Value类型为java.lang.String的数据库不能将 转换为JSONArray。

和：

错误在fillproductlist（）：显示java.lang.NullPointerException

我不是在的Java/Android的非常好，这是我第一次问这个问题这里。我无法理解我的应用程序的哪一层可能存在问题（我的Java代码，PHP或数据库代码）？

代码快照：

private void fillProductList() { 

    if (utils.isInternet() 
      && CustomHttpClient.isAddressOk(Utils.LINK_PRODUCTS)) { 

     final int from = bid.size(); 
     final int nr = 5; 
     long sqliteSize = db.size(mySqlDatabase.TABLE_BOOKS); 
     if (from == 0) { 
      // we add the post variables and values for the request 
      postParameters.add(new BasicNameValuePair("from", String 
        .valueOf(0).toString())); 
      postParameters.add(new BasicNameValuePair("nr", String.valueOf(
        nr).toString())); 
     } else { 
      postParameters.add(new BasicNameValuePair("from", String 
        .valueOf(from).toString())); 
      postParameters.add(new BasicNameValuePair("nr", String.valueOf(
        nr).toString())); 
     } 
     postParameters.add(new BasicNameValuePair("title", titleSearch)); 
     postParameters.add(new BasicNameValuePair("code", codeSearch)); 
     postParameters.add(new BasicNameValuePair("module", moduleSearch)); 
     if (sortOrder != null) 
      postParameters.add(new BasicNameValuePair("order", sortOrder)); 
     if (sortType != null) 
      postParameters.add(new BasicNameValuePair("by", sortType)); 
     task = new RequestTask("books", postParameters); 
     task.setOnTaskCompleted(new OnTaskCompletedListener() { 
      public void onTaskStarted() { 
       if (!rlLoading.isShown()) { 
        rlLoading.startAnimation(fadeIn()); 
        rlLoading.setVisibility(View.VISIBLE); 
       } 
       IS_PRODUCTS_TASK = true; 
      } 

      public void onTaskCompleted(String result) { 
       try { 
        if (result != "") { 
         // Enter the remote php link 
         // we convert the response into json array 
         jarray = utils.getJarrayFromString(result); 
         int mysqlSize = (jarray.getJSONObject(0) 
           .getInt("numRows")); 
         Log.i(DEBUG, "From " + from + " to " + mysqlSize); 
         if (from <= mysqlSize) { 
          int rows; 
          // we check to see if there is 0 
          if (jarray.length() > 0) { 

           Log.i(DEBUG, 
             "From " 
               + from 
               + " to " 
               + Math.floor(mysqlSize/nr) 
               * nr); 
           if (from + 5 <= Math.floor(mysqlSize/nr) 
             * nr) { 
            rows = jarray.length(); 
           } else { 
            rows = mysqlSize % nr + 1; 
            Utils.IS_ENDED_PRODUCT_LIST = true; 
           } 
           ArrayList<String> list = new ArrayList<String>(); 
           for (int i = 1; i < rows; i++) { 
            JSONObject row = jarray 
              .getJSONObject(i); 
            bid.add(row.getInt("bid")); 
            bTitle.add(row.getString("bTitle")); 
            bCode.add(row.getString("bCode")); 
            bPrice.add(row.getString("bPrice") 
              + "£"); 
            bDescription.add(row 
              .getString("bDescription")); 
            bModule.add(row.getString("bModule")); 
            bImage.add(Utils.PATH 
              + row.getString("bImage")); 
            list.add(row.getString("bImage")); 
            // we check if this id already exists in the db, if it doesn't exists w create new one 
            if (!db.hasIDbooks(row.getInt("bid"))) 
             db.createRowOnBooks(
               row.getInt("bid"), 
               row.getString("bTitle"), 
               row.getString("bCode"), 
               row.getString("bPrice"), 
               row.getString("bDescription"), 
               row.getString("bModule"), 
               Utils.PATH 
                 + row.getString("bImage"), 
               row.getString("bSpecialOffer"), 
               row.getInt("bSpecialDiscount"), 
               row.getString("bDateAdded")); 
            Log.i(DEBUG, 
              row.getString("bDescription")); 
           } 
           new DownloadImages(list, bAdapter) 
             .execute(); 
          } 
         } 
         postParameters.removeAll(postParameters); 
        } else { 
         Utils.IS_ENDED_PRODUCT_LIST = true; 
         if (rlLoading.isShown()) { 
          rlLoading.startAnimation(fadeOut()); 
          rlLoading.setVisibility(View.INVISIBLE); 
         } 
        } 
       } catch (Exception e) { 
        Log.e(DEBUG, 
          "Error at fillProductList(): " + e.toString()); 
       } 
      } 
     }); 
     task.execute(); 
    } else { 
     // if we are not connected on internet or somehow the link would not work, then we will take the rows stored in sqlite db 
     if (db.size(mySqlDatabase.TABLE_BOOKS) > 0) { 
      Cursor cursor = db.getBookssRows(mySqlDatabase.TABLE_BOOKS); 
      cursor.moveToFirst(); 
      while (!cursor.isAfterLast()) { 
       bid.add(cursor.getInt(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BID))); 
       bTitle.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BTITLE))); 
       bCode.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BCODE))); 
       bPrice.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BPRICE)) + "£"); 
       bDescription.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BDESCRIPTION))); 
       bModule.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BMODULE))); 
       bImage.add(cursor.getString(cursor 
         .getColumnIndex(mySqlDatabase.KEY_BIMAGE))); 
       cursor.moveToNext(); 
      } 
      bAdapter.notifyDataSetChanged(); 
      Utils.IS_ENDED_PRODUCT_LIST = true; 
     } 
    } 
} 

Answer 1

在OnTaskCompleted前

jarray = utils.getJarrayFromString(result); 

添加日志条目与

Log.i(DEBUG,result); 

我怀疑你得到一个空值result

if(result!="") 

不确保有效的值。 干杯