使用 Maatwebsite/Laravel-Excel 生成 csv 文件 如何使标题 returns 动态数组

Question

在laravel 5.8生成我使用的csv文件 https://github.com/Maatwebsite/Laravel-Excel 插件，它工作正常，但是当我使用 headings 方法生成 header https://docs.laravel-excel.com/3.1/exports/mapping.html

我需要 headers，具体取决于我从数据库获得的结果集：

<?php

namespace App\Exports;

use Auth;
use Maatwebsite\Excel\Concerns\FromCollection;
use Maatwebsite\Excel\Concerns\WithHeadings;

class exportSearchResults implements FromCollection, WithHeadings
{
    public function collection()
    {
        $searchResultRows = SearchResult
            ::getByUserList($this->user_list_id)
            ->select( 'source_id' )
            ->groupBy( 'source_id' )
            ->orderBy('source_id', 'asc')
            ->get()
            ->toArray();
            ...
        return $searchResultRows;
    }

    public function headings(): array
    {
        return [
            'field',
            'value',
        ];
        // I need Somehow to return content of this array based on $searchResultRows array in collection method
    }

}

有这样的方法吗？

Answer 1

你可以使用这样的东西：

<?php

namespace App\Exports;

use Auth;
use Maatwebsite\Excel\Concerns\FromCollection;
use Maatwebsite\Excel\Concerns\WithHeadings;

class exportSearchResults implements FromCollection, WithHeadings
{
    private $searchResultRows;

    public function collection()
    {
        return $this->searchResultRows;
    }


    public function headings(): array {
         $this->searchResultRows = SearchResult::getByUserList($this->user_list_id)
            ->select( 'source_id' )
            ->groupBy( 'source_id' )
            ->orderBy('source_id', 'asc')
            ->get()
            ->toArray();
            ...
        if ($this->searchResultRows ...){
        return [
            'field',
            'value',
        ];
        } else {
          return ...
        }
    }

}