php - 属性在方法1中设置后在方法2中为空

Question

希望您能帮我解决这个问题!

Index.php

include_once 'files.class.php';
$file_object = new FileObject('resources');
$file_object->ReturnCurrentDirectoryList();

files.class.php

class FileObject{
public $directory_list;

    function __construct($current_directory_in){
        $this->directory_list = $this->BuildCurrentDirectoryList($current_directory_in);
    }

    function BuildCurrentDirectoryList($current_directory_in){
        $i = 0;
        $iterator = new DirectoryIterator($current_directory_in);

        foreach ($iterator as $fileinfo){
            if ($fileinfo->isDir()){
                $this->directory_list[$i]['pathname'] = $fileinfo->getPathname();
            }elseif($fileinfo->isFile()){
                $this->directory_list[$i]['filename'] = $fileinfo->getFilename();
            }
            $i++;
        }
    }

    function ReturnCurrentDirectoryList(){
        var_dump($this->directory_list);
    }
}

最后，返回的是

null

但是应该返回的是

array  0 =>  array 'pathname' => string 'resources\.',  1 => array 'pathname' => string 'resources\..', 2 =>  array 'pathname' => string 'resources\Images'

我对类/方法有点陌生..

Answer 1

这是错误的:

$this->directory_list = $this->BuildCurrentDirectoryList($current_directory_in);

您分配给 $this->directory_list 但 BuildCurrentDirectoryList 不返回任何内容。该函数只有副作用，没有返回值。

删除赋值，使构造函数看起来像这样，您应该可以开始了:

$this->directory_list = array(); //I like to initialise arrays to the empty array
$this->BuildCurrentDirectoryList($current_directory_in);