PHP 函数不返回数据。显示错误

Question

include("include/session.php");

    class createcountdown
        {
        public $start;
        public $howlong;
        public function get(){
        $this->start = $session->start; // $session->start Returns data from Mysql: 0000-00-00 00:00:00
        $this->howlong = $session->howlong; // $session->howlong Returns data from Mysql: 300
        $diff = $this->start-3600 + $this->howlong-time();

        if($this->start + $this->howlong > time()){
           list($h,$min,$sec)=explode(":",date("H:i:s",$diff));
           $sum = $this->start + $this->howlong-time();
           return $sum;
        }
    }

    $obj = new createcountdown();
    $result = $obj->get();
    echo $result;

Answer 1

您正在使用未定义变量 $session 的属性：

$this->start = $session->start;
$this->howlong = $session->howlong;

如果它是全局对象，请在访问它之前使用 global $session; 。

Answer 2

看起来问题是 get() 中的 if 后面缺少大括号。

当我在 list($h,$min,$sec)=explode(":",date("H:i:s",$diff)); 之后添加大括号时，代码运行没有错误。

Answer 3

请关闭类}操作符missiong

include("include/session.php");

    class createcountdown
        {
        public $start;
        public $howlong;
        public function get(){
        $this->start = $session->start; // $session->start Returns data from Mysql: 0000-00-00 00:00:00
        $this->howlong = $session->howlong; // $session->howlong Returns data from Mysql: 300
        $diff = $this->start-3600 + $this->howlong-time();

        if($this->start + $this->howlong > time()){
           list($h,$min,$sec)=explode(":",date("H:i:s",$diff));
           $sum = $this->start + $this->howlong-time();
           return $sum;
        }
    }
 }

    $obj = new createcountdown();
    $result = $obj->get();
    echo $result;

Answer 4

你可以试试这个：

include("include/session.php");

    class createcountdown
        {
        public $start;
        public $howlong;
        public $session; // add 
        public function get(){
       // $this->start = $session->start; // $session->start Returns data from Mysql: 0000-00-00 00:00:00
         $this->start = $this->session->start; // change here
        // $this->howlong = $session->howlong; // $session->howlong Returns data from Mysql: 300
        $this->howlong = $this->session->howlong; // change here

        $diff = $this->start-3600 + $this->howlong-time();

        if($this->start + $this->howlong > time()){
           list($h,$min,$sec)=explode(":",date("H:i:s",$diff));
           $sum = $this->start + $this->howlong-time();
           return $sum;
        }
    }
 }

    $obj = new createcountdown();
    $obj->session = $session // which is globaly define
    $result = $obj->get();
    echo $result;