无法在 Android 中解析 JSON 响应

我知道这个问题很常见，但提出的所有解决方案似乎都不适合我的情况。我正在尝试从 PHP 网络服务检索 JSON 响应，但不断收到此错误

Error parsing data org.json.JSONException: Value <br of type java.lang.String
W/System.err: org.json.JSONException: No value for success

而下面是我认为与错误相关的我的Android代码

        // getting JSON response from PHP web service
JSONObject returnedJSONObj = listsJSONParser.makeHttpRequest(Constant.URL
                + "RetrieveListSVC.php", "GET", params);
Log.d("Returned JSON ", String.valueOf(returnedJSONObj));
success = returnedJSONObj.getInt(Constant.TAG_SUCCESS);
Log.d("JSON Success Value", String.valueOf(success));
if (success == 1){
// do stuff}

在日志Returned JSON我在 LogCat 中收到的输出是

D/Returned JSON: {"androidid":"1"}

但是日志JSON Success Value没有输出。如第一块所示，成功没有价值。PHP已经给了我，我没有编写它，因为我对PHP几乎一无所知，所以服务可能是有问题的服务。这是可能相关的代码

<?php
define('IEM_PATH', '../admin/com');
require_once('../admin/includes/config.php');
require_once('../admin/com/lib/IEM.class.php');
require_once ('../admin/com/lib/IEM/DBFACTORY.class.php');
require_once ('../admin/com/lib/IEM/baseAPI.class.php');
require_once ('../admin/com/lib/API/USERS.class.php');
require_once ('../admin/com/lib/IEM/baseRecord.class.php');
require_once ('../admin/com/lib/record/Users.class.php');
    function GetLists($userid = 0, $getUnconfirmedCount = false) {
        $userid = $_REQUEST['userID'];
        if (!$userid) {
        trigger_error('This user object is not loaded with any user.... You will need to supply the userid as a parameter.', E_USER_NOTICE);
            return false;
        }

        if (!$userid) {
            $userid = $this->userid;
        }
        // If user is a "System Admin" or a "List Admin", allow to access all lists
      /*  if ($userid == $this->userid) {
            if ($this->ListAdmin() || $this->listadmintype == 'a') {
                $userid = 0;
            }
        }
      */
        require_once('../admin/functions/api/lists.php');
        $listapi = new Lists_API();
        $returnA =  $listapi->GetListByUserID($userid, $getUnconfirmedCount);
        $returnResult1 = array();
            foreach ($returnA as $key => $value) { 
                //$lists[] = $key;
                $returnResult["contactList"][] = array("listID" => $returnA[$key]['listid'], "name" => $returnA[$key]['name']);
            }
       $returnResult["success"] = 1;
       echo json_encode($returnResult) ;
    }
    //}
    GetLists();

我提问的目的是我想知道问题出在 Java 还是 PHP 代码上？我是否正确处理了 JSON 响应，还是应该以另一种方式处理。