GY_zhishiku_admin/app/Model/Category.php

<?php
namespace App\Model;

use Illuminate\Database\Eloquent\Model;
use Encore\Admin\Traits\AdminBuilder;
use Encore\Admin\Traits\ModelTree;

class Category extends Model
{
    use ModelTree,AdminBuilder;

    public $table       = "jm_category";
    protected $fillable = ['parent_id' , 'category_name' , 'id'];


    // 展示树状调用
    public function __construct(array $attributes = [])
    {
        parent::__construct($attributes);
        $this->setParentColumn('parent_id');
        $this->setOrderColumn( 'id');
        $this->setTitleColumn( 'category_name');
    }


    // 获取分类名称
    public static function getCategoryName($parent_id)
    {
        $category = self::find($parent_id);
        return $category->category_name;
    }


    public static function getCategory()
    {
        return self::getTree(self::all() , 0, 0);
    }


    public static function getTree($arr , $pid , $step)
    {
        global $tree;
        //$arr = self::all();
        if($arr->isEmpty()) {
            return [];
        } else {
            foreach ($arr as $key => $val) {
                if ($val['parent_id'] == $pid) {
                    $flg = str_repeat('└-', $step);
                    $val['category_name'] = $flg . $val['category_name'];
                    $tree[] = $val;
                    self::getTree($arr , $val['id'], $step + 1);
                }
            }

            if(empty($tree)) return [0 => '1级'];
            $selectOption = [];
            foreach ($tree as $option) {
                $selectOption[$option->id] = $option->category_name;
            }
            $selectOption[0] = 'Root';
            return $selectOption;
        }
    }

}