Php 创建Laravel Nova镜头-不在对象上下文中时使用$this

我正在试用幼虫新星，特别是镜头

我已经跟着导游走了

但它抱怨在这一行中使用了$this

   $query->select($this->columns())

带着错误

$this when not in object context

这是密码

<?php

namespace App\Nova\Lenses;

use Laravel\Nova\Fields\ID;
use Illuminate\Http\Request;
use Laravel\Nova\Fields\Text;
use Laravel\Nova\Lenses\Lens;
use Laravel\Nova\Fields\Number;
use Illuminate\Support\Facades\DB;
use Laravel\Nova\Http\Requests\LensRequest;

class MostValuableUsers extends Lens
{
    /**
     * Get the query builder / paginator for the lens.
     *
     * @param  \Laravel\Nova\Http\Requests\LensRequest  $request
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @return mixed
     */
    public static function query(LensRequest $request, $query)
    {
        return $request->withOrdering($request->withFilters(
            $query->select($this->columns())
                  ->join('licenses', 'users.id', '=', 'licenses.user_id')
                  ->orderBy('revenue', 'desc')
                  ->groupBy('users.id', 'users.name')
        ));
    }

    /**
     * Get the columns that should be selected.
     *
     * @return array
     */
    protected function columns()
    {
        return [
            'users.id',
            'users.name',
            DB::raw('sum(licenses.price) as revenue'),
        ];
    }

    /**
     * Get the fields available to the lens.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function fields(Request $request)
    {
        return [
            ID::make('ID', 'id'),
            Text::make('Name', 'name'),

            Number::make('Revenue', 'revenue', function ($value) {
                return '$'.number_format($value, 2);
            }),
        ];
    }

    /**
     * Get the filters available for the lens.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    public function filters(Request $request)
    {
        return [];
    }

    /**
     * Get the URI key for the lens.
     *
     * @return string
     */
    public function uriKey()
    {
        return 'most-profitable-users';
    }
}

---

问题是在静态函数中使用$this（一个不知道
$this
上下文的函数）。我建议在静态函数中创建一个实例（如果您确实需要静态函数）。
您的函数是静态的，因此不能使用
$this
namespace App\Nova\Lenses;

use Laravel\Nova\Fields\ID;
use Illuminate\Http\Request;
use Laravel\Nova\Fields\Text;
use Laravel\Nova\Lenses\Lens;
use Laravel\Nova\Fields\Number;
use Illuminate\Support\Facades\DB;
use Laravel\Nova\Http\Requests\LensRequest;

class MostValuableUsers extends Lens
{
    /**
     * Get the query builder / paginator for the lens.
     *
     * @param  \Laravel\Nova\Http\Requests\LensRequest  $request
     * @param  \Illuminate\Database\Eloquent\Builder  $query
     * @return mixed
     */
    public static function query(LensRequest $request, $query)
    {
        $mostValuableUser = new MostValuableUsers();

        return $request->withOrdering($request->withFilters(
            $query->select($mostValuableUser->columns())
                  ->join('licenses', 'users.id', '=', 'licenses.user_id')
                  ->orderBy('revenue', 'desc')
                  ->groupBy('users.id', 'users.name')
        ));
    }

    ...