在函数内传递变量

Question

我正在尝试使用API​​来安排会话。变量$ tutor_id，$ tutorname，$ date3，$ topic等已经提前设置

<?php   
class ScheduleClass
{
function ScheduleClass($secretAcessKey,$access_key,$webServiceUrl)
{

    require_once("AuthBase.php");
    $authBase = new AuthBase($secretAcessKey,$access_key);
    $method = "create";
    $requestParameters["signature"]=$authBase-
    >GenerateSignature($method,$requestParameters);
    $requestParameters["presenter_id"] =$tutor_id;
    $requestParameters["presenter_name"] = $tutorname ;  
    $requestParameters["start_time"] = $date3;
    $requestParameters["title"]=$topic; //Required
    $requestParameters["duration"]="10"; //optional
    $requestParameters["time_zone"]="Asia/Kolkata"; //optional
    $requestParameters["attendee_limit"]=""; //optional
    $requestParameters["control_category_id"]=""; //optional
    $requestParameters["create_recording"]=""; //optional
    $requestParameters["return_url"]= $return_url; //optional
    $requestParameters["status_ping_url"]=""; //optional
                $requestParameters["language_culture_name"]="en-us";

foreach($requestParameters as $x => $x_value) {
echo "Key=" . $x . ", Value=" . $x_value;
echo "<br>";}
}//end function
}
require_once("keys.php");
$obj=new ScheduleClass($secretAcessKey,$access_key,$webServiceUrl);
?>

然而输出如下：

Key=access_key, Value=abcde
Key=timestamp, Value=1513613770
Key=method, Value=create
Key=signature, Value=abcde
Key=presenter_id, Value=
Key=presenter_name, Value=
Key=start_time, Value=
Key=title, Value=
Key=duration, Value=10
Key=time_zone, Value=Asia/Kolkata
Key=attendee_limit, Value=
Key=control_category_id, Value=
Key=create_recording, Value=

即未传递在类/ Function外部设置的变量。 欢迎任何帮助。