新數據替換ArrayList中的舊數據

Question

我有一個應用程序，我需要在列表視圖中顯示數據。爲此我使用自定義Adapter.To存儲我的信息我已創建模型類與getter和setter.The信息我得到的是Json格式。所以我解析它並將其存儲在我的模型類中。我有用戶ArrayList來存儲info.But我的概率是從Json數組解析數據新數據替換ArrayList中的舊數據。 例如

loop 1 
data=1,2,5 
ArrayList at [0]=1,2,5 

loop 2 
data=2,2,2 
ArrayList at [0]=2,2,2 
      [1]=2,2,2 

現在爲什麼會這樣？

模型類

公共類SearchModel {

public class SearchModel { 

    private String category, minExp, maxExp, postedOn, counts, applied, position, desc, type, hour, status, expiryDate, address, gender, religion, summary, requestId, requestorId; 

    public SearchModel(String category, String minExp, String maxExp, String postedOn, String counts, String applied, String position, String desc, String type, String hour, String status, String expiryDate, String address, String gender, String religion, String summary, String requestId, String requestorId) { 
     this.category = category; 
     this.minExp = minExp; 
     this.maxExp = maxExp; 
     this.postedOn = postedOn; 
     this.counts = counts; 
     this.applied = applied; 
     this.position = position; 
     this.desc = desc; 
     this.type = type; 
     this.hour = hour; 
     this.status = status; 
     this.expiryDate = expiryDate; 
     this.address = address; 
     this.gender = gender; 
     this.religion = religion; 
     this.summary=summary; 
     this.requestId = requestId; 
     this.requestorId = requestorId; 
    } 
} 

異步類

protected void onPostExecute(String s) { 
     values = new ArrayList<SearchModel>(); 
     data = new SearchModel(); 

     super.onPostExecute (s); 
     if (!s.trim().contains ("Table")) { 
      Crouton.makeText ((android.app.Activity) c, "Nothing found", Style.INFO).show(); 
     } else { 
      try { 

       JSONObject jsonObject = new JSONObject (s); 
       JSONObject NewDataSet = jsonObject.getJSONObject ("NewDataSet"); 
       if (NewDataSet.get ("Table") instanceof JSONObject) { 
        JSONObject table = NewDataSet.getJSONObject ("Table"); 
        data.setAddress (table.getString ("Address")); 
        data.setCounts (table.getString ("Candidate_Counts")); 
        values.add (data); 

       } else if (NewDataSet.get ("Table") instanceof JSONArray) { 
        JSONArray tableArray = NewDataSet.getJSONArray ("Table"); 
        for (int i = 0; i < tableArray.length(); i++) { 
         JSONObject table = tableArray.getJSONObject (i); 
         data.setAddress (table.getString ("Address")); 
         data.setCounts (table.getString ("Candidate_Counts")); 
         values.add (data); 

        } 

       } 


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

Answer 1

看來問題是，你不通過創建每次SearchModel一個新實例for循環，因此values.add (data);只是將另一個參考添加到相同的SearchModel實例。也就是說，ArrayList中的每個項都指向一個對象。嘗試更改您的代碼如下：

protected void onPostExecute(String s) { 
    values = new ArrayList<SearchModel>(); 
    // data = new SearchModel(); << Remove this 

    // super.onPostExecute (s); << You don't need this, by the way. 
    if (!s.trim().contains ("Table")) { 
    ... 
    ... 
     if (NewDataSet.get ("Table") instanceof JSONObject) { 
      JSONObject table = NewDataSet.getJSONObject ("Table"); 

      data = new SearchModel(); // << Add this 
      data.setAddress (table.getString ("Address")); 
      data.setCounts (table.getString ("Candidate_Counts")); 
      values.add (data); 
     } else if (NewDataSet.get ("Table") instanceof JSONArray) { 
      JSONArray tableArray = NewDataSet.getJSONArray ("Table"); 
      for (int i = 0; i < tableArray.length(); i++) { 
       JSONObject table = tableArray.getJSONObject (i); 

       data = new SearchModel(); // << Add this 
       data.setAddress (table.getString ("Address")); 
       data.setCounts (table.getString ("Candidate_Counts")); 
       values.add (data); 
      } 
     } 
     ... 
     ...