ionic中的用户名和密码无效

Question

当我尝试登录离子应用程序时，我获得了无效的登录... API是使用Slim框架构建的。不知道错误来自哪里，我也尝试使用邮递员，但仍然收到相同的错误。

下面是我的API登录功能

function login() {

        $request = \Slim\Slim::getInstance()->request();
        $data = json_decode($request->getBody());

        try {

            $db = getDB();
            $userData ='';
            $sql = "SELECT user_id,email, username FROM users WHERE (username=:username or email=:username) and password=:password ";
            $stmt = $db->prepare($sql);
            $stmt->bindParam("username", $data->username, PDO::PARAM_STR);
            $password=hash('sha256',$data->password);
            $stmt->bindParam("password", $password, PDO::PARAM_STR);
            $stmt->execute();
            $mainCount=$stmt->rowCount();
            $userData = $stmt->fetch(PDO::FETCH_OBJ);

            if(!empty($userData))
            {
                $user_id=$userData->user_id;
                $userData->token = apiToken($user_id);
            }

            $db = null;
             if($userData){
                   $userData = json_encode($userData);
                    echo '{"userData": ' .$userData . '}';
                } else {
                   echo '{"error":{"text":"Invalid username or password"}}';
                }        
        }
        catch(PDOException $e) {
            echo '{"error":{"text":'. $e->getMessage() .'}}';
        }
    }