從數組構建遞歸嵌套菜單

Question

我正在嘗試構建一個遞歸菜單，完成后看起來像這樣，具有無限數量的嵌套項目：

Homepage
Services
  Members
  Brokers
  Insurers
Products

我的數據通過我表中的一個簡單的parent_id列鏈接在一​​起。

我目前已設法獲取表中的所有頁面，並根據其parent_id （見下文）將它們添加到數組中。

Array
(
    [0] => 0-0-1 0-1-2 0-2-12 0-3-27 0-4-28 0-5-29 0-6-30 0-7-31 0-8-33 
    [2] => 2-0-3 2-0-6 2-0-7 2-0-8 
    [3] => 3-0-4 3-0-5 
    [8] => 8-0-9 8-0-10 
    [12] => 12-0-13 12-0-20 
    [13] => 13-0-14 13-1-15 13-2-17 13-3-16 13-4-19 13-5-18 13-9-34 
    [20] => 20-0-21 20-1-22 20-2-24 20-3-23 20-4-26 20-5-25 20-6-11 
)

這被格式化為 [ parent_id ] => parent_id - sort_order - id parent_id - sort_order - id等等。

到目前為止，我的代碼如下：

$sqlGetDropdownPages = "SELECT * FROM `cms_staticPages` ORDER BY `sortOrder` ASC";
$qryGetDropdownPages = mysql_query($sqlGetDropdownPages) or die(mysql_error());
$resGetDropdownPages = mysql_fetch_assoc($qryGetDropdownPages);
$totGetDropdownPages = mysql_num_rows($qryGetDropdownPages);

do {    

    $pageArray[$resGetDropdownPages['parent_id']] .= $resGetDropdownPages['parent_id'].'-'.$resGetDropdownPages['sortOrder'].'-'.$resGetDropdownPages['id'].' ';

} while($resGetDropdownPages = mysql_fetch_assoc($qryGetDropdownPages));

ksort($pageArray);

foreach($pageArray as $i => $value) {

    $explodePages = explode(' ',$value);

    foreach(array_filter($explodePages) as $i2 => $page) {

        $pageInfoExplode = explode('-',$page);

        $getPageInfo = mysql_fetch_assoc(mysql_query("SELECT * FROM `cms_staticPages` WHERE `id` = '".$pageInfoExplode[2]."'"));

        echo $getPageInfo['identifier'].'<br />';

    }

}

此時撞到了一堵磚牆，不知道下一步該怎么做。

我試圖盡可能地解釋這一點，所以如果需要任何澄清，請詢問。

如何實現這一目標？

Answer 1

我會首先按 id 索引所有菜單項（頁面）。 在第二個循環中，將菜單項與其父項相關聯並跟蹤頂級項。

我會這樣做的方法之一（Render方法只是一個例子）：

$sqlGetDropdownPages = "SELECT * FROM `cms_staticPages` ORDER BY `sortOrder` ASC";
$qryGetDropdownPages = mysql_query($sqlGetDropdownPages) or die(mysql_error());

//indexing pages by id
while ($pageRow = mysql_fetch_assoc($qryGetDropdownPages)) {
    $menuItems[$pageRow['id']] = new MenuItem($pageRow);
}

//associating pages with parents
foreach ($menuItems as $menuItem) {
    if ($menuItem->hasParent()) {
        $menuItem->addToParent($menuItems);
    } else {
        $topLevel[] = $menuItem;
    }
}

//$topLevel is an array of menuItems without parents
$render = '<ul>';
foreach ($topLevel as $menuItem) {
    $render .= $menuItem->render(true);
}
$render .= '</ul>';

MenuItem 類看起來像這樣

class MenuItem {

    /**
     * @var array
     */
    private $data;

    /**
     * @var MenuItem[]
     */
    private $children = array();

    /**
     * @var MenuItem
     */
    private $parent;

    /**
     * @param array $data
     */
    public function __construct($data) {
        $this->data = $data;
    }

    /**
     * Finds the parent in the collection and adds itself to it
     * @param MenuItem[] $menuItems
     */
    public function addToParent($menuItems) {
        if (isset($menuItems[$this->data['parent_id']])) {
            $this->parent = $menuItems[$this->data['parent_id']];
            $this->parent->addChild($this);
        }
    }

    /**
     * @return bool
     */
    public function hasParent() {
        return empty($this->data['parent_id']);
    }

    /**
     * @param MenuItem $child
     */
    public function addChild(MenuItem $child) {
        $this->children[] = $child;
    }

    /**
     * Renders the menu with ul li
     * @param bool $withChildren
     * @return string
     */
    public function render($withChildren = false) {
        $render = '<li>' . $this->data['identifier'] . '</li>';

        if ($withChildren) {
            $render .= '<ul>';
            foreach ($this->children as $child) {
                $render .= $child->render(true);
            }
            $render .= '</ul>';
        }

        return $render;
    }

}

Answer 2

這是我使用 PHP 中的遞歸函數為 Zurb Foundation 構建嵌套菜單的示例代碼。 非常簡單和干凈。

// call the function
build_menu();

//----------------------------

// recursive function
function build_menu($parent = "", $tab=""){
    $sql = "SELECT * FROM cat WHERE parent='$parent' ORDER BY category ASC";
    $q = mysql_query($sql);
    if (mysql_num_rows($q)) {
        if (empty($parent)):
            print $tab."<ul>\n";
        else:
            print $tab."<ul class='dropdown'>\n";
        endif;
        while($d = mysql_fetch_object($q)) {
            $has_child = mysql_num_rows(mysql_query("select * from cat where parent='$d->code'") );
            $tag = ($has_child ? " class='has-dropdown'" : "");
            $nl  = ($has_child ? "\n" : "");

            print $tab."\t"."<li".$tag."><a href='cat.php?cat=$d->code'>$d->category</a>$nl";

            if ($has_child) build_menu($d->code, $tab."\t");

            print $tab."</li>\n";
        }
        print $tab."</ul>\n";
    }
}

Answer 3

假設從數據庫中提取所有菜單項后，輸出如下輸出。

$items = [
[
    'id' => '1',
    'parent_id' => '0',
    'title' => 'Menu 1',
],
[
    'id' => '2',
    'parent_id' => '0',
    'title' => 'Menu 2',
],
[
    'id' => '3',
    'parent_id' => '2',
    'title' => 'Menu 2 1',
],
[
    'id' => '4',
    'parent_id' => '0',
    'title' => 'Menu 3',
],
[
    'id' => '5',
    'parent_id' => '4',
    'title' => 'Menu 3 1',
],
[
    'id' => '6',
    'parent_id' => '5',
    'title' => 'Menu 3 1 1',
],
[
    'id' => '7',
    'parent_id' => '5',
    'title' => 'Menu 3 1 2',
],
[
    'id' => '8',
    'parent_id' => '7',
    'title' => 'Menu 3 1 2 1',
],
[
    'id' => '9',
    'parent_id' => '4',
    'title' => 'Menu 3 2',
],
[
    'id' => '10',
    'parent_id' => '0',
    'title' => 'Menu 4',
]];

讓我們寫一個函數來處理Array格式的數據並返回html

/**
 * Recursive and prints the elements of the given parent id.
 * @param $items
 * @param string $parentId
 */
function buildNestedItems($items, $parentId = "0", $wrapperTag = 'ul', $itemTag = 'li')
{
    // Parent items control
    $isParentItem = false;
    foreach ($items as $item) {
        if ($item['parent_id'] === $parentId) {
            $isParentItem = true;
            break;
        }
    }

    // Prepare items
    $html = "";
    if ($isParentItem) {
        $html .= "<$wrapperTag>";
        foreach ($items as $item) {
            if ($item['parent_id'] === $parentId) {
                $html .= "<$itemTag>" . $item['title'] . "</$itemTag>";
                $html .= buildNestedItems($items, $item['id']);
            }
        }
        $html .= "</$wrapperTag>";
    }
    return $html;
}

讓我們打印准備好的 html i 頁面

<div class="menu">
    <?php echo buildNestedItems($items); ?>
</div>