PHP递归菜单功能

Question

I have a very similar situation to this post

PHP: nested menu with a recursive function, expand only some nodes (not all the tree)

and I need some help...

Here is the (partial) contents of my $menuJSONArray variable (used when calling the function):

    Array
(
[0] => Array
    (
        [Menu_IDX] => 1
        [Order] => 1
        [Name] => History
        [Parent] => 
        [Path] => History
        [Link] => 
    )

[1] => Array
    (
        [Menu_IDX] => 2
        [Order] => 25
        [Name] => Review
        [Parent] => 
        [Path] => Review
        [Link] => Review
    )

[2] => Array
    (
        [Menu_IDX] => 3
        [Order] => 35
        [Name] => Past Medical History
        [Parent] => 
        [Path] => Past Medical History
        [Link] => Past Medical History
    )
 [3] => Array
    (
        [Menu_IDX] => 4
        [Order] => 45
        [Name] => Item 1
        [Parent] => 0
        [Path] => Item 1
        [Link] => Item 1
    )
 [4] => Array
    (
        [Menu_IDX] => 5
        [Order] => 55
        [Name] => Item 2
        [Parent] => 0
        [Path] => Item 2
        [Link] => Item 2
    )
 [5] => Array
    (
        [Menu_IDX] => 6
        [Order] => 65
        [Name] => Item 3
        [Parent] => 0
        [Path] => Item 3
        [Link] => Item 3
    )
)

and so on...

I am using the function below but I keep getting stuck in the loop at the first item. Really need some help wrapping my brain around this function. Thank you all ahead of time, this community rocks!!

///RECURSIVE MENU
function recursive($parent, $array) {
$has_children = false; //set value of has children to false by default
foreach($array as $key => $value) {  //loop through the array as key-value pairs
    if ($value['Parent'] == $parent) {  //if the value of Parent field is equal to parent variable   
        if ($has_children === false && $parent) {  //if children is false but parent is not null, this is a sub item
            $has_children = true;  //children is true
            echo '<ul>' ."\n";  //create parent menu ul
        } //otherwise just create the item
        echo '<li>' . "\n";  //create li for parent menu item
        echo '<a href="'.$value['Path'].'">' . $value['Name'] . '</a>' . " \n";  //create link for menu item
            recursive($key, $array); //create sub menu
        echo "</li>\n"; //end parent menu item
    }
}
if ($has_children === true && $parent) echo "</ul>\n"; //end parent menu
}

?>
<?php echo recursive(0, $menuJSONArray); ?></ul>

What I get in return is:

<ul>



<li>
<a href="History">History</a> 
<li>
<a href="History">History</a> 
<li>
<a href="History">History</a> 
<li>
<a href="History">History</a> 
<li>
<a href="History">History</a> 
<li>
<a href="History">History</a>

Can't seem to get out of this loop. Thanks!!

PS I am not concerned with the collapsing of the tree etc. from the referenced post as I will be handling that with jquery and css. I just cannot get the proper output of the menu syntax.

Answer 1

As I agree with @Tim Withers I start to solve problem from preparing current array:

function prepareMenu($array)
{
  $return = array();
  //1
  krsort($array);
  foreach ($array as $k => &$item)
  {
    if (is_numeric($item['Parent']))
    {
      $parent = $item['Parent'];
      if (empty($array[$parent]['Childs']))
      {
        $array[$parent]['Childs'] = array();
      }
      //2
      array_unshift($array[$parent]['Childs'],$item);
      unset($array[$k]);
    }
  }
  //3
  ksort($array);
  return $array;
}

Some explanation.

1. This is a weak point as I assumed that order of your menu array will be constant. Assumed order is:
   • top elements first
   • after that children
   • after that children of children
   • so on..
2. Here is a place where I add a child at beginning of array to save original order.
3. Rollback to original order.

Then function to build menu:

function buildMenu($array)
{
  echo '<ul>';
  foreach ($array as $item)
  {
    echo '<li>';
    echo $item['Name'];
    if (!empty($item['Childs']))
    {
      buildMenu($item['Childs']);
    }
    echo '</li>';
  }
  echo '</ul>';
}

With this and proper array order, no matter how deep rabbit hole is - you have your tree.

Usage:

$menu = prepareMenu($menu);
buildMenu($menu);

Of course... There must be better way... :-P

---

EDIT:

For array (a little midification [next child]):

$menu = array(
array(
        'Menu_IDX' => '1',
        'Order' => '1',
        'Name' => 'History',
        'Parent' => '',
        'Path' => 'History',
        'Link' => '',
    ),
array
    (
        'Menu_IDX' => '2',
        'Order' => '25',
        'Name' => 'Review',
        'Parent' => '',
        'Path' => 'Review',
        'Link' => 'Review',
    ),
array
    (
        'Menu_IDX' => '3',
        'Order' => '35',
        'Name' => 'Past Medical History',
        'Parent' => '',
        'Path' => 'Past Medical History',
        'Link' => 'Past Medical History',
    ),
array
    (
        'Menu_IDX' => '4',
        'Order' => '45',
        'Name' => 'Item 1',
        'Parent' => '0',
        'Path' => 'Item 1',
        'Link' => 'Item 1',
    ),
array
    (
        'Menu_IDX' => '5',
        'Order' => '55',
        'Name' => 'Item 2',
        'Parent' => '0',
        'Path' => 'Item 2',
        'Link' => 'Item 2',
    ),
array
    (
        'Menu_IDX' => '6',
        'Order' => '65',
        'Name' => 'Item 3',
        'Parent' => '0',
        'Path' => 'Item 3',
        'Link' => 'Item 3',
    ),
array
    (
        'Menu_IDX' => '7',
        'Order' => '65',
        'Name' => 'Item 31',
        'Parent' => '5',
        'Path' => 'Item 31',
        'Link' => 'Item 31',
    )
);

Output will be:

• History
  • Item 1
  • Item 2
  • Item 3
    • Item 31
  • Review
  • Past Medical History

Answer 2

Plenty of detail in your question, that's great.

Looking at the code, the first issue I see is with the line:

if ($value['Parent'] == $parent) {

The first time you enter the foreach loop, $value['Parent'] is NULL , and $parent is 0 .

Because you are doing a == comparison, this evaluates to TRUE . Try instead:

if ($value['Parent'] === $parent) {

Note the === . This also checks the data type and requires it to match as well.

The second issue will then be with the line:

if ($has_children === false && $parent) {  //if children is false but parent is not null, this is a sub item

The comment makes it clear that you want to check that $parent is not null, but you aren't doing that, you are casting the integer value of $parent to a Boolean, so 0 will be treated as FALSE , and anything else as TRUE .

Try instead:

if ($has_children === false && !is_null($parent)) {  //if children is false but parent is not null, this is a sub item.