在列表中添加值后，无法检索出来

原问题来自于CSDN问答频道，更多解决方案见：http://ask.csdn.net/questions/1879

问题描述：

在一个列表中我使用add(int,Object)方法添加了一个值，但是当我使用get(int)方法检索值的时候，却还是获得上次添加的值，并不是这次新添加的值。
谁能给出适当的建议呢？
我使用的下面的代码：

public static List getCompanyName(String user_id) {



    List<CustomerList> fetchDatefromID = new ArrayList<CustomerList>();

    CustomerList tempProgram = new CustomerList();

    String result = "";

    InputStream is = null;



    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

    nameValuePairs.add(new BasicNameValuePair("q", "" + user_id));



    // http post

    try {

        HttpClient httpclient = new DefaultHttpClient();

        HttpPost httppost = new HttpPost(

                "https://erestaurantonline.co.uk/kernow_mobile/customer_search.php?");

        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

        HttpResponse response = httpclient.execute(httppost);

        HttpEntity entity = response.getEntity();

        is = entity.getContent();

    } catch (Exception e) {

        Log.e("log_tag", "Error in http connection " + e.toString());

    }

    // convert response to string

    try {

        BufferedReader reader = new BufferedReader(new InputStreamReader(

                is, "iso-8859-1"), 8);

        StringBuilder sb = new StringBuilder();

        String line = null;

        while ((line = reader.readLine()) != null) {

            sb.append(line + "\n");

        }

        is.close();

        result = sb.toString();

    } catch (Exception e) {

        Log.e("log_tag", "Error converting result " + e.toString());

    }



    // parse json data

    try {

        JSONArray jArray = new JSONArray(result);

        for (int i = 0; i < jArray.length(); i++) {

            JSONObject json_data = jArray.getJSONObject(i);



            if (json_data.getString("company") != null) {

                tempProgram.setCompanyName(json_data.getString("company"));

                tempProgram.setID(json_data.getString("id"));

                fetchDatefromID.add(i, tempProgram);

            }



        }



    } catch (JSONException e) {

        Log.e("log_tag", "Error parsing data " + e.toString());

    }



    for (int i = 0; i < fetchDatefromID.size(); i++) {

        Log.v("log_tag","DataMy  :  "+fetchDatefromID.get(i).getCompanyName().toString());

    }

    return fetchDatefromID;

}

解决方案：

把下面的代码：

if (json_data.getString("company") != null) {

                tempProgram.setCompanyName(json_data.getString("company"));

                tempProgram.setID(json_data.getString("id"));

                fetchDatefromID.add(i, tempProgram);

            }

换成：

if (json_data.getString("company") != null) {

                tempProgram = new CustomerList();

                tempProgram.setCompanyName(json_data.getString("company"));

                tempProgram.setID(json_data.getString("id"));

                fetchDatefromID.add(i, tempProgram);

            }

否则，list中的每一项都要引用同样的对象，那样的话总是显示你最后一次输入的数据。