用PHP递归生成嵌套导航

Question

I have a php class that looks like this:

class $nav_node {
    public $id;
    public $page_name;
    public $parent_id;
    public $page_content;
}

My goal is to build a function that takes a single one of these nav_nodes and shoves it into an existing nested navigation structure.

$nav_nodes = [];
function add_node($new_node) {

}

I want to build the nested navigation structure simply by using html's

<ul> and <li> tags ( nested )

This is what the structure would look like when done

Thing
    thing2
       thing3
       thing4
    thing5
    thing6
       thing7
Thing8
    thing9

Here was my first attempt, but I didn't really see this going anywhere.

function add_node($new_node) {
        global $nav_nodes; 

        if ( isset($nav_nodes[$new_node->id]) && !is_array($nav_nodes[$new_node->id]) ) {
            $nav_node[$new_node->id] = [];
        }

        $nav_nodes[$new_node->id][] = $new_node;

        // Display "new" nested structure    
}

I imagine recursion can be used somewhere. I was thinking that even if this function correctly builds the structure of the array, I still need to somehow display it all. Maybe that's a separate function? Maybe that separate display function is the one that is recursive? I think it would be best if this could be a single function.

Anyways, Thanks for your help!!

Answer 1

Here is an answer I created which I've adapted from http://www.jugbit.com/php/php-recursive-menu-with-1-query/ which is a really great answer. Very minimal/simple code.

class nav_node {
    public $id;
    public $page_name;
    public $parent_id;
    public $page_content;
    public $items;

    public function __construct($id, $page_name, $parent_id, $page_content)
    {
        $this->id = $id;
        $this->page_name = $page_name;
        $this->parent_id = $parent_id;
        $this->page_content = $page_content;
    }
}

class nav {
    public function generate($nodes)
    {
        ob_start();
        //echo var_dump(nav::create_array($nodes));
        echo '<ul>';

        foreach ($nodes as $node)
        {
            echo '<li>'.$node->page_name.'</li>';
            if (count($node->items) > 0)
            {
                echo nav::generate($node->items);
            }
        }

        echo '</ul>';
        return ob_get_clean();
    }

    public function create_array($nodes, $parent = 0)
    {
        $out = array();
        foreach($nodes as $node){
            if($node->parent_id == $parent){
                $out[$node->id] = $node;
                $out[$node->id]->items = nav::create_array($nodes, $node->id);
            }
        }

        return $out;
    }
}

$nodes[] = new nav_node(
    1,
    'home',
    null,
    'hello world'
);
$nodes[] = new nav_node(
    2,
    'about',
    null,
    'hello world'
);
$nodes[] = new nav_node(
    3,
    'company',
    2,
    'hello world'
);
$nodes[] = new nav_node(
    4,
    'contact',
    3,
    'hello world'
);
$nodes[] = new nav_node(
    6,
    'offices',
    3,
    'hello world'
);
$nodes[] = new nav_node(
    7,
    'staff',
    3,
    'hello world'
);

//var_dump($nodes);

nav::generate(nav::create_array($nodes));

Output:

• home
• about
• company
• contact
• offices
• staff