将JSON转换为模型对象Android

我刚刚在Android中使用JSON，并且从JSON创建模型对象时遇到了一些问题。如果有人知道任何好的教程或资源，这将是很好的更多细节，我会很感激他们。到目前为止，我一直在关注Vogella和Bignerdranch Android书籍的教程。将JSON转换为模型对象Android

我能够拉入JSON并创建一个JSON对象，但是我的调查没有保存。

这里是我试图解析JSON：

[ 
     { 
      "title": "Pepsi or Coke?", 
      "id": 1, 
      "questions": [ 
       { 
        "id": 1, 
        "title": "Which pop do you prefer?", 
        "single_response": true, 
        "answers": [ 
         { 
          "title": "Pepsi", 
          "id": 1 
         }, 
         { 
          "title": "Coke", 
          "id": 2 
         }, 
         { 
          "title": "Mountain Dew", 
          "id": 3 
         } 
        ] 
       }, 
       { 
        "id": 2, 
        "title": "What's your age?", 
        "single_response": true, 
        "answers": [ 
         { 
          "title": "18-24", 
          "id": 4 
         }, 
         { 
          "title": "25-34", 
          "id": 5 
         }, 
         { 
          "title": "35-50", 
          "id": 6 
         }, 
         { 
          "title": "50+", 
          "id": 7 
         } 
        ] 
       }, 
       { 
        "id": 3, 
        "title": "What's your political association?", 
        "single_response": true, 
        "answers": [ 
         { 
          "title": "Republican", 
          "id": 8 
         }, 
         { 
          "title": "Democrat", 
          "id": 9 
         } 
        ] 
       } 
      ] 
     } 
    ]

我检索像这样JSON：

byte[] getUrlBytes(String urlSpec) throws IOException { 
      URL url = new URL(urlSpec); 
      HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 

      try { 
       ByteArrayOutputStream out = new ByteArrayOutputStream(); 
       InputStream in = connection.getInputStream(); 

       if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) { 
        return null; 
       } 

       int bytesRead = 0; 
       byte[] buffer = new byte[1024]; 
       while ((bytesRead = in.read(buffer)) > 0) { 
        out.write(buffer, 0, bytesRead); 
       } 
       out.close(); 
       return out.toByteArray(); 
      } finally { 
       connection.disconnect(); 
      } 
     } 

     public String getUrl(String urlSpec) throws IOException { 
      return new String(getUrlBytes(urlSpec)); 
     }

这里的地方我分析它：

public ArrayList<Survey> getSurveys(String apiKey) throws JSONException { 
    ArrayList<Survey> surveys = new ArrayList<Survey>(); 

    try { 
     String url = Uri.parse(ENDPOINT).buildUpon().appendQueryParameter("auth_token", apiKey).build().toString(); 
     String jsonString = getUrl(url); 
     Log.i(TAG, "Received json string: " + jsonString); 

     try { 
      JSONArray array = new JSONArray(jsonString); 

      for (int i = 0; i < array.length(); i ++) { 
       JSONObject object = array.getJSONObject(i); 
       Log.i(TAG, "Object is: " + object.toString()); 
      } 

      for (int i = 0; i < array.length(); i++) { 
       Survey survey = new Survey(array.getJSONObject(i)); 
       surveys.add(survey); 
       Log.i(TAG, "Survey is: " + survey.toString()); 
      } 
     } catch (Exception e) { 
      Log.e(TAG, "Survey didn't save"); 
     } 

    } catch (IOException ioe) { 
     Log.e(TAG, "Failed to retrieve surveys: " + ioe); 
    } 
    return surveys; 
}

我假设问题出在我创建的调查方法本身，因为JSON对象创建正确，但调查不是s AVING。任何想法，我要去哪里错了？

public Survey(JSONObject json) throws JSONException { 
     mId = UUID.fromString(json.getString("id")); 
     if (json.has("title")) { 
      mTitle = json.getString("title"); 
     } 
}

与往常一样，任何帮助都非常感谢！

来源

2014-03-02 Tom Hammond

原来，问题在于我试图将使用JSON发送的int id转换为UUID。

只要数据类型匹配，项目被正确创建。

来源

2014-03-02 21:19:19

将JSON转换为模型对象Android

回答

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