doudoulb1234 2016-11-17 18:04
浏览 72
已采纳

PHP:有没有办法在对象构造函数中使用全局变量?

I have a php script that is intended to be user-editable, with some options set right at the beginning, including allowable extensions for image files.

Later on, I want to use this in an object constructor to set whether a file is an image or not.

$extensions = ["jpg", "jpeg", "gif", "png"];

class directory_entry {

  function __construct($name) {

    $this->name = $name;

    $extension = pathinfo($name, PATHINFO_EXTENSION);
    $this->is_image = in_array(strtoupper($extension), $extensions); // throws an error

    $this->image = $this->is_image($name);

  }
}

This doesn't work because I can't call $extensions from inside an class(?). Is there a way to do it without including $extensions in every object of this class? Seems nuts to declare objects with

$files[] = new directory_entry($value, $extensions);

and have every instance of this class have a copy of the same array?

  • 写回答

2条回答 默认 最新

  • dopt85756 2016-11-18 08:02
    关注

    The solution that seems to work best for what I'm trying to do (bear in mind that I'm a PHP and OOP n00b) is the globals keyword:

    $extensions = ["jpg", "jpeg", "gif", "png"];
    
    class directory_entry {
    
      function __construct($name) {
    
        $this->name = $name;
    
        $extension = pathinfo($name, PATHINFO_EXTENSION);
        global $extensions; //use the global version of $extensions
        $this->is_image = in_array(strtoupper($extension), $extensions); // works!
    
        $this->image = $this->is_image($name);
    
      }
    }
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(1条)

报告相同问题?

悬赏问题

  • ¥15 输入程序运行仿真后,烟雾值不实时检测,变成固定值
  • ¥15 lingo,求错误原因,这段代码哪里不对,求帮助!
  • ¥20 数据排序,可选择排序方向
  • ¥15 修改一下代码,考虑进程到达时间不同的情况
  • ¥15 帮我看看这是个啥题,带解题过程和结果,条件如下FCF = 290471.33 g1 = 15% r = 8% g2 = 4% n = 5
  • ¥15 edem模拟颗粒不显示或者生成失败
  • ¥15 Python代码编写
  • ¥15 php 将rtmp协议转hls协议,无法播放
  • ¥20 python代码编写
  • ¥20 使用MPI广播数据遇到阻塞