php - XML“树”到多级html列表

Question

我有一个 XML 文件，我想将其显示为多级列表

<items>
  <item>
    <parent_id>1</parent_id>  
    <id>1876</id>
    <name>foobar1</name>
  </item>
  <item>
    <parent_id>1876</parent_id>
    <id>1877</id>
    <name>foobar11</name>
  </item>
  <item>
    <parent_id>1877</parent_id>
    <id>1878</id>
    <name>foobar111</name>
  </item>
  <item>
    <parent_id>1877</parent_id>
    <id>1879</id>
    <name>foobar112</name>
  </item>
  <item>
    <parent_id>1877</parent_id>
    <id>1880</id>
    <name>foobar113</name>
  </item>
...
</items>

我想显示如下：

<ul>
    <li>foobar1</li>
    <li>
      <ul>
        <li>foobar11</li>
        <li>
          <ul>
            <li>foobar111</li>
            <li>foobar112</li>
            <li>foobar113</li>
          </ul>
        </li>
      </ul>
    </li>
...
</ul>

我尝试循环执行（我使用的是 simplexml）：

    $catxml = simplexml_load_file('file.xml');  
    $nodes=$catxml->xpath("//item");    
    $gile=0;
    $ile=0;

    foreach($nodes as $node) {
        $par = $node->parent_id;
        $id = $node->id;
        $naz = $node->name;

        if($par=='1'){ $gile++;  $ile++; echo '<li><a href="#url">'.$id.'-'.$naz.'</a></li>';
        settype($id,'integer');         
            foreach($nodes as $nodea) {
                $apar = $nodea->parent_id;
                $aid = $nodea->id;
                $anaz = $nodea->name;
                settype($aid,'integer');
                $apoczatek='';
                if($apar!='1' AND $apar==$id AND $aid>$id){ $ile++; if($apoczatek!=''){echo '</ul></li>';}echo '<li><ul><li><a href="#url">'.$aid.'-'.$anaz.'</a></li>';
                    foreach($nodes as $nodea) {
                        $bpar = $nodea->parent_id;
                        $bid = $nodea->id;
                        $bnaz = $nodea->name;
                        $bpoczatek='';
                        settype($bid,'integer');
                        if($bpar==$aid AND $bid>$aid){ $ile++; if($bpoczatek!=''){echo '</ul>';}echo '<ul><li><a href="#url">'.$bid.'-'.$bnaz.'</a></li>';
                            foreach($nodes as $nodea) {
                                $cpar = $nodea->parent_id;
                                $cid = $nodea->id;
                                $cnaz = $nodea->name;
                                $cpoczatek='';
                                settype($cid,'integer');
                                if($cpar==$bid AND $cid>$bid){ $ile++; if($cpoczatek!=''){echo '</ul>';}echo '<ul><li><a href="#url">'.$cid.'-'.$cnaz.'</a></li>';
                                    foreach($nodes as $nodea) {
                                        $dpar = $nodea->parent_id;
                                        $did = $nodea->id;
                                        $dnaz = $nodea->name;
                                        $dpoczatek='';
                                        settype($did,'integer');
                                        if($dpar==$cid AND $did>$cid){ $ile++; if($dpoczatek!=''){echo '</ul>';}echo '<ul><li><a href="#url">'.$did.'-'.$dnaz.'</a></li>';
                                            foreach($nodes as $nodea) {
                                                $epar = $nodea->parent_id;
                                                $eid = $nodea->id;
                                                $enaz = $nodea->name;
                                                $epoczatek='';
                                                settype($eid,'integer');
                                                if($epar==$did AND $eid>$did){ $ile++; if($epoczatek!=''){echo '</ul>';}echo '<ul><li><a href="#url">'.$eid.'-'.$enaz.'</a></li>';

                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

但它没有用 - 错过<ul>和</ul>标签

对我的方法有什么建议吗？还有其他方法吗？

Answer 1

我将递归函数用于递归数据。我也注释掉了// echo "</li>\n<li>";：你想要的 HTML 结构需要它，但我不喜欢它。

$catxml = simplexml_load_file('file.xml');  
$nodes=$catxml->xpath("//item");

$children = array();

foreach($nodes as $node) {
    $parent_id = (int) $node->parent_id;
    if(! array_key_exists ($parent_id, $children)) {
        $children[$parent_id] = array();
    }
    $children[$parent_id][] = $node;
}

function renderChildrenList( &$children, $id) {
    echo "\n<ul>";
    foreach($children[$id] as $node) {
        echo "\n<li>" . $node->id . '-' . $node->name;

        $child_id = (int) $node->id;
        if(array_key_exists($child_id, $children)) {
            // echo "</li>\n<li>";
            renderChildrenList($children, $child_id);
        }

        echo "</li>";
    }
    echo "\n</ul>";
}

// I assume root_id=1
renderChildrenList( $children, 1, 0);