2014-10-03 63 views
0

我返回一個接受字符串值的JSONArray,但每次運行我的應用程序時都會收到下面的錯誤消息。我的(GetCityDetails)方法返回一個空值。下面是我的語法和logcat信息。我究竟做錯了什麼?由於JSONObject無法轉換爲JSONArray - 外部數據庫

org.json.JSONException:類型的值null org.json.JSONObject $ 1不能被轉換成JSONArray

在網上被退回

JSON數組,多數民衆贊成 [{ 「城市」: 「海厄利亞」} { 「城市」: 「代託納比奇」},{ 「城市」: 「好萊塢」},{ 「城市」: 「瑪麗安娜」}]

@SuppressLint("NewApi") 
public JSONArray GetCityDetails(String StateID) { 

    @SuppressWarnings("deprecation") 
    String url = "http://mywebsite.com/getCity.php?StateID="+URLEncoder.encode(StateID); 

    HttpEntity httpEntity = null; 

    try{ 

     DefaultHttpClient httpClient = new DefaultHttpClient(); 
     HttpGet httpGet = new HttpGet(url); 

     HttpResponse httpResponse = httpClient.execute(httpGet); 

     httpEntity = httpResponse.getEntity(); 


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

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


    JSONArray jsonArray = new JSONArray(); 
    if(httpEntity !=null){ 
     try{ 

      InputStream entityResponse = httpEntity.getContent(); 
      String entityResponseAfterFunctionCall = convertInputStreamIntoString(entityResponse); 

      Log.e("Entity Response From GetCityDetails Class: ", entityResponseAfterFunctionCall); 

       jsonArray = new JSONArray(entityResponseAfterFunctionCall); 
     } catch(JSONException e){ 
      e.printStackTrace(); 
     } catch(IOException e){ 
      e.printStackTrace(); 
     } 
    } 

    return jsonArray; 
} 

public String convertInputStreamIntoString(InputStream entityResponse) throws IOException{ 

    StringWriter writer = new StringWriter(); 
    IOUtils.copy(entityResponse, writer); 
    String theString = writer.toString(); 
    return theString; 
} 


} 

logcat的

01-01 19:11:36.719: E/Entity Response From GetCityDetails Class:(3938): null 
01-01 19:11:36.729: W/System.err(3938): org.json.JSONException: Value null of type org.json.JSONObject$1 cannot be converted to JSONArray 
01-01 19:11:36.729: W/System.err(3938):  at org.json.JSON.typeMismatch(JSON.java:107) 
01-01 19:11:36.729: W/System.err(3938):  at org.json.JSONArray.<init>(JSONArray.java:91) 
01-01 19:11:36.729: W/System.err(3938):  at org.json.JSONArray.<init>(JSONArray.java:103) 
01-01 19:11:36.729: W/System.err(3938):  at com.example.bhphprices.com.APIConnector.GetCityDetails(APIConnector.java:120) 
01-01 19:11:36.729: W/System.err(3938):  at com.example.bhphprices.com.CityDetailsActivity$GetAllStates.doInBackground(CityDetailsActivity.java:64) 
01-01 19:11:36.729: W/System.err(3938):  at com.example.bhphprices.com.CityDetailsActivity$GetAllStates.doInBackground(CityDetailsActivity.java:1) 
01-01 19:11:36.739: W/System.err(3938):  at android.os.AsyncTask$2.call(AsyncTask.java:185) 
01-01 19:11:36.739: W/System.err(3938):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 
01-01 19:11:36.739: W/System.err(3938):  at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
01-01 19:11:36.739: W/System.err(3938):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 
01-01 19:11:36.739: W/System.err(3938):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 
01-01 19:11:36.739: W/System.err(3938):  at java.lang.Thread.run(Thread.java:1019) 

回答

0

documentation指出可以通過傳遞具有json格式的集合或字符串來實例化JSONArray,但是您傳遞的是空值,如出現在日誌的第一行中。

我會建議你調試convertInputStreamIntoString並檢查你是否收到你的請求的錯誤迴應,或者其他的事情正在取得字符串。

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