在Laravel 5中创建类别的嵌套列表

Question

Laravel刚起步，并且正在尝试为我的应用创建树状类别结构。这是我以前使用过的代码，但仍然无法实现我想要的代码。我的控制器：

public function index()
{
    $categories = Category::with('children')->get();

    return view('backend.categories.index')->with('categories', $categories);
}

我的类别模型：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Category extends Model
{
    protected $guarded = ['id'];

    public function parent()
    {
        return $this->belongsTo('App\Category', 'parent_id');
    }

    public function children()
    {
        return $this->hasMany('App\Category', 'parent_id');
    }
}

我的看法：

<table class="table table-bordered table-hover">
                <thead>
                    <tr>
                        <th>Name</th>
                        <th>Description</th>
                        <th>Slug</th>
                        <th>Action</th>
                    </tr>
                </thead>
                <tbody>
                @foreach ($categories as $category)
                    {{--@foreach ($category->children as $children)--}}
                    <tr>
                        <td>{{ $category->name }}</td>
                        <td>{{ $category->description }}</td>
                        <td>{{ $category->slug }}</td>
                        <td><a class="edit" href="{!! action('Admin\CategoriesController@edit', $category->id) !!}" title="Edit"><i class="fa fa-pencil-square-o"></a></i> <a class="delete" href="{!! action('Admin\CategoriesController@destroy', $category->id) !!}" title="Are you sure you want to delete?"><i class="fa fa-trash-o"></i></a></td>
                        @foreach ($category->children as $children)
                            <tr>
                                <td>{{ $children->name }}</td>
                                <td>{{ $children->description }}</td>
                                <td>{{ $children->slug }}</td>
                                <td></td>
                            </tr>
                        @endforeach
                    </tr>
                </tbody>
                    {{--@endforeach--}}
                @endforeach
            </table>

我正在尝试产生如下结构：

• 时尚配饰
  • 包袋
  • 布料
• 手提电话
  • 平板电脑
  • 智能手机

编辑有我的数据库结构：

+-------------+------------------+------+-----+---------------------+----------------+
| Field       | Type             | Null | Key | Default             | Extra          |
+-------------+------------------+------+-----+---------------------+----------------+
| id          | int(10) unsigned | NO   | PRI | NULL                | auto_increment |
| name        | varchar(255)     | NO   |     | NULL                |                |
| slug        | varchar(255)     | NO   |     | NULL                |                |
| parent_id   | int(11)          | YES  |     | NULL                |                |
| description | text             | NO   |     | NULL                |                |
| created_at  | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
| updated_at  | timestamp        | NO   |     | 0000-00-00 00:00:00 |                |
+-------------+------------------+------+-----+---------------------+----------------+

Answer 1

您当前正在加载所有类别（包括子类别），然后循环遍历它们。您只想加载根类别（没有父级的类别）。为此，请将控制器方法更改为仅加载 is 的parent_id类别null。

$categories = Category::whereNull('parent_id')->with('children')->get();